PHELPS DODGE CORP
SC 14D1, 1999-09-03
PRIMARY SMELTING & REFINING OF NONFERROUS METALS
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<PAGE>   1

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549
                            ------------------------
                                 SCHEDULE 14D-1
              TENDER OFFER STATEMENT PURSUANT TO SECTION 14(D)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                            ------------------------

                          CYPRUS AMAX MINERALS COMPANY
                           (NAME OF SUBJECT COMPANY)

                                CAV CORPORATION
                                      AND

                            PHELPS DODGE CORPORATION
                                   (BIDDERS)

                           COMMON STOCK, NO PAR VALUE
           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)

                        (TITLE OF CLASSES OF SECURITIES)
                            ------------------------
                            496902107 (COMMON STOCK)

                     (CUSIP NUMBER OF CLASS OF SECURITIES)
                            ------------------------
                             S. DAVID COLTON, ESQ.
                       VICE PRESIDENT AND GENERAL COUNSEL
                            PHELPS DODGE CORPORATION
                           2600 NORTH CENTRAL AVENUE
                          PHOENIX, ARIZONA 85004-3014
                                 (602) 234-8100
                            ------------------------
                                   COPIES TO:

<TABLE>
<S>                                            <C>
            MICHAEL W. BLAIR, ESQ.                         STEPHEN R. VOLK, ESQ.
             DEBEVOISE & PLIMPTON                         DAVID W. HELENIAK, ESQ.
               875 THIRD AVENUE                             599 LEXINGTON AVENUE
              NEW YORK, NY 10022                          NEW YORK, NEW YORK 10022
                (212) 909-6000                           TELEPHONE: (212) 848-4000
</TABLE>

                           CALCULATION OF FILING FEE

<TABLE>
<CAPTION>
  ----------------------------------------------------
  ----------------------------------------------------
   TRANSACTION VALUATION        AMOUNT OF FILING FEE
  ----------------------------------------------------
  <S>                         <C>
      $1,557,511,057*                 $311,502
  ----------------------------------------------------
  ----------------------------------------------------
</TABLE>

[X]  Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
     and identify the filing with which the offsetting fee was previously paid.
     Identify the previous filing by registration statement number, or the Form
     or Schedule and the date of its filing.

<TABLE>
<S>                                <C>
Amount Previously Paid:            $404,698
Form or Registration No.:          333-86061
Filing Party:                      Phelps Dodge Corporation
Date Filed:                        August 27, 1999
</TABLE>

*  For purposes of calculating the filing fee only. This calculation assumes
   that 90,454,100 shares of common stock, no par value per share, of Cyprus
   Amax Minerals Company will be exchanged for shares of common stock, $6.25 par
   value per share, of Phelps Dodge Corporation. Pursuant to Rules 0-11(d) and
   0-11(a)(4) of the Securities Exchange Act of 1934, as amended, the filing fee
   was based upon the average of the high and low prices of Cyprus Amax Minerals
   Company common stock on August 31, 1999, as reported on the New York Stock
   Exchange Composite Tape.

** The filing fee is calculated by taking 1/50 of 1% of the Transaction
   Valuation, pursuant to Rule 0-11(d) of the Exchange Act.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2

<TABLE>
<S>        <C>                                                          <C>
- ---------------------------------------------------------------------------
  1        NAME OF REPORTING PERSONS:
           Phelps Dodge Corporation
           S.S. OR I.R.S. IDENTIFICATION NUMBER OF ABOVE PERSON:
           13-1808503
- ---------------------------------------------------------------------------
  2        CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP
           (a) [ ] (b) [ ]
- ---------------------------------------------------------------------------
  3        SEC USE ONLY
- ---------------------------------------------------------------------------
  4        SOURCES OF FUNDS
           NA*
- ---------------------------------------------------------------------------
  5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
           PURSUANT TO ITEM 2(e) or 2(f)
           [ ]
- ---------------------------------------------------------------------------
  6        CITIZENSHIP OR PLACE OF ORGANIZATION
           New York
- ---------------------------------------------------------------------------
  7        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
           100 shares of common stock, no par value
- ---------------------------------------------------------------------------
  8        CHECK IF THE AGGREGATE AMOUNT IN ROW (7) EXCLUDES CERTAIN
           SHARES
           [ ]
- ---------------------------------------------------------------------------
  9        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (7)
           Nominal
- ---------------------------------------------------------------------------
  10       TYPE OF REPORTING PERSON
           CO
- ---------------------------------------------------------------------------
</TABLE>

* All consideration provided in the form of Phelps Dodge Corporation common
  stock, par value $6.25 per share.
<PAGE>   3

<TABLE>
<S>        <C>                                                          <C>
- ---------------------------------------------------------------------------
  1.       NAME OF REPORTING PERSONS:
           CAV Corporation
           S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON:
           N/A
- ---------------------------------------------------------------------------
  2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF GROUP
           (a) [ ] (b) [ ]
- ---------------------------------------------------------------------------
  3.       SEC USE ONLY
- ---------------------------------------------------------------------------
  4.       SOURCE OF FUNDS
           N/A*
- ---------------------------------------------------------------------------
  5.       CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
           PURSUANT TO ITEM 2(e) or 2(f)
           [ ]
- ---------------------------------------------------------------------------
  6.       CITIZENSHIP OR PLACE OF ORGANIZATION
           Delaware
- ---------------------------------------------------------------------------
  7.       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
           100 shares of common stock, no par value
- ---------------------------------------------------------------------------
  8.       CHECK IF THE AGGREGATE AMOUNT IN ROW (7) EXCLUDES CERTAIN
           SHARES
           [ ]
- ---------------------------------------------------------------------------
  9.       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (7)
           Nominal
- ---------------------------------------------------------------------------
  10.      TYPE OF REPORTING PERSON
           CO
- ---------------------------------------------------------------------------
</TABLE>

* All consideration provided in the form of Phelps Dodge Corporation common
  stock, par value $6.25 per share.
<PAGE>   4

     This Tender Offer Statement relates to the exchange offer by Phelps Dodge
Corporation ("Phelps Dodge"), through its wholly-owned subsidiary, CAV
Corporation, a Delaware corporation ("Purchaser") to exchange any and all of the
outstanding shares of common stock, no par value per share, and the associated
preferred share purchase rights (each, a "Cyprus Amax Share" and collectively,
the "Cyprus Amax Shares"), of Cyprus Amax Minerals Company, a Delaware
corporation, for 0.3135 shares of common stock, par value $6.25 per share, of
Phelps Dodge (the "Phelps Dodge Common Shares"), upon the terms and subject to
the conditions set forth in Phelps Dodge's prospectus, dated September 2, 1999
(the "Prospectus"), and the related Letter of Transmittal.

ITEM 1.  SECURITY AND SUBJECT COMPANY.

     (a) The name of the subject company is Cyprus Amax Minerals Company, a
Delaware corporation ("Cyprus Amax"), which has its principal executive offices
at 9100 East Mineral Circle, Englewood, CO 80112.

     (b) The class of securities to which this statement relates is the Cyprus
Amax Shares. The information set forth on the cover page and under the caption
"The Offer" in the Prospectus, a copy of which is attached hereto as Exhibit
(a)(1), is incorporated herein by reference. As of August 3, 1999, there were
outstanding 90,454,100 Cyprus Shares according to the Cyprus Amax Current Report
on Form 10-Q for the period ended June 30, 1999.

     (c) The information set forth under the caption "Market Prices and
Dividends" in the Prospectus is incorporated herein by reference.

ITEM 2.  IDENTITY AND BACKGROUND.

     (a)-(d) and (g)  This Statement is filed by Phelps Dodge and the Purchaser.
The information concerning the name, state or other place of organization,
principal business and address of the principal office of Phelps Dodge is set
forth under the captions "Summary -- the Companies -- Phelps Dodge Corporation"
and "The Companies -- Phelps Dodge Corporation" in the Prospectus. The Purchaser
is a corporation organized under the laws of the State of Delaware and has its
principal business address at 2600 North Central Avenue, Phoenix, Arizona
85004-3014. The Purchaser's only assets are 100 Cyprus Amax Shares and the
Purchaser has no operations. Information concerning the name, business address,
present principal occupation or employment and the name, principal business and
address of any corporation or other organization in which such employment or
occupation is conducted, material occupations, positions, offices or employments
during the last five years and citizenship of each of the executive officers and
directors of Phelps Dodge and the Purchaser is set forth in Schedule A of the
Prospectus and is incorporated herein by reference.

     (e)-(f)  During the last five years, neither of Phelps Dodge nor the
Purchaser, and, to the best knowledge of Phelps Dodge and the Purchaser, none of
the persons listed in Schedule A of the Prospectus has been (i) convicted in a
criminal proceeding (excluding traffic violations or similar misdemeanors) or
(ii) a party to a civil proceeding of a judicial or administrative body of
competent jurisdiction and as a result of such proceeding was or is subject to a
judgment, decree or final order enjoining future violations of, or prohibiting
activities subject to, federal or state securities laws or finding any violation
of such laws.

ITEM 3.  PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH THE SUBJECT COMPANY.

     (a)-(b)  The information set forth under the captions "Summary -- The
Offer," "Background of the Offer" and "The Offer -- Relationships with Cyprus
Amax" in the Prospectus is incorporated herein by reference.

ITEM 4.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

     (a) The information set forth under the captions "Summary -- The Offer" and
"The Offer" in the Prospectus is incorporated herein by reference.

     (b) Not applicable.
<PAGE>   5

     (c) Not applicable.

ITEM 5.  PURPOSE OF THE TENDER OFFER AND PLANS OR PROPOSALS OF THE BIDDER.

     (a)-(g)  The information set forth under the captions "The Offer -- Effect
of Offer on Market for Cyprus Amax Shares; Registration Under the Exchange Act,"
"The Offer -- Purpose of Our Offer; the Phelps Dodge/Cyprus Amax Merger,"
"Comparison of Rights of Holders of Phelps Dodge Shares and Cyprus Amax Shares"
and "Market Prices and Dividends" in the Prospectus is incorporated herein by
reference.

ITEM 6.  INTEREST IN SECURITIES OF THE SUBJECT COMPANY.

     (a)-(b)  Information set forth in Annex B of the preliminary proxy
statement of Phelps Dodge on Schedule 14A, dated August 27, 1999, a copy of
which is attached hereto as Exhibit (f), is incorporated herein by reference.
Such information is current through the date hereof.

ITEM 7. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO
        THE SUBJECT COMPANY'S SECURITIES.

     None.

ITEM 8.  PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED.

     The information set forth under the caption "The Offer -- Fees and
Expenses" in the Prospectus and under the caption "Solicitation of Proxies" in
the Phelps Dodge preliminary proxy statement of Phelps Dodge on Schedule 14A,
dated August 27, 1999, is incorporated herein by reference.

ITEM 9.  FINANCIAL STATEMENTS OF CERTAIN BIDDERS.

     The information set forth under the captions "Summary," "The
Companies -- Phelps Dodge" and "Unaudited Pro Forma Combined Financial
Information" in the Prospectus is incorporated herein by reference. The
financial statements contained in Item 8 of Phelps Dodge's Annual Report on Form
10-K for the year ended December 31, 1998 and in Phelps Dodge's Quarterly
Reports on Form 10-Q for the periods ended March 31, 1999 and June 30, 1999 are
incorporated herein by reference. Phelps Dodge files annual, quarterly and
special reports, proxy statements and other information with the Securities and
Exchange Commission (the "SEC"). Such reports may be read and copied at the
public reference room of the SEC) at 450 Fifth Street, N.W., Washington, D.C.
20549, or at the SEC's public reference rooms in New York, New York and Chicago,
Illinois. The SEC may be reached at 1-800-SEC-0330 for further information on
the public reference rooms. SEC filings are also available to the public from
commercial document retrieval services and at the Internet world wide web site
maintained by the SEC at www.sec.gov. In addition, these Phelps Dodge reports
are available without charge upon request to: Corporate Secretary, Phelps Dodge
Corporation, 2600 North Central Avenue, Phoenix, AZ 85004-3014, telephone (602)
234-8598.

     The incorporation by reference herein of the above-referenced financial
information does not constitute an admission that such information is material
to a decision by a security holder of Cyprus Amax whether to exchange, tender or
hold securities being sought in the Offer.

ITEM 10.  ADDITIONAL INFORMATION.

     (a) None.

     (b)-(c)  The information set forth under the captions "Background of the
Offer" and "The Offer -- Conditions of Our Offer" in the Prospectus is
incorporated herein by reference.

     (d)  The information set forth under the caption "The Offer -- Effect of
Offer on Market for Cyprus Amax Shares; Registration under the Exchange Act" in
the Prospectus is incorporated herein by reference.

     (e)  The information set forth under the caption "The Offer -- Litigation"
in the Prospectus is incorporated herein by reference.
<PAGE>   6

     (f)  The information set forth in the Prospectus and the related Letter of
Transmittal, attached as Exhibits (a)(1) and (2) hereto, is incorporated herein
by reference.

ITEM 11.  MATERIAL TO BE FILED AS EXHIBITS.

     (a)(1)  Prospectus of Phelps Dodge dated September 2, 1999.

     (a)(2)  Form of Letter of Transmittal.

     (a)(3)  Form of Notice of Guaranteed Delivery.

     (a)(4)  Form of Letter from Morgan Stanley & Co. Incorporated to Brokers,
             Dealers, Commercial Banks, Trust Companies and Nominees.

     (a)(5)  Form of Letter from Brokers, Dealers, Commercial Banks, Trust
             Companies and Nominees to Clients.

     (a)(6)  Form of Guidelines for Certification of Taxpayer Identification
             Number on Substitute Form W-9.

     (a)(7)  Form of Summary Advertisement as published in The Wall Street
             Journal on September 3, 1999.

     (b)      None.

     (c)      None.

     (d)      Tax opinion of Shearman & Sterling.

     (e)      See exhibit (a)(1).

     (f)      Preliminary Proxy Statement of Phelps Dodge dated August 27, 1999
              (incorporated by reference).
<PAGE>   7

     After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

                                          Phelps Dodge Corporation

                                          By /s/ RAMIRO G. PERU
                                            Name: Ramiro G. Peru
                                            Title:  Chief Financial Officer and
                                                Senior Vice President

September 3, 1999
<PAGE>   8

     After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

                                          CAV Corporation

                                          By /s/ RAMIRO G. PERU
                                            Name: Ramiro G. Peru
                                            Title:  Director, Vice President and
                                                    Treasurer

September 3, 1999

<PAGE>   1

LOGO
                            Phelps Dodge Corporation
            Offer to Exchange Each Outstanding Share of Common Stock
             (Including Associated Preferred Share Purchase Rights)
                                       of
                          Cyprus Amax Minerals Company
                       For 0.3135 Shares of Common Stock
                                       of
                            Phelps Dodge Corporation

     THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
CITY TIME, ON OCTOBER 1, 1999 UNLESS EXTENDED. SHARES TENDERED PURSUANT TO THIS
OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE EXPIRATION OF THE OFFER.

     We are offering to exchange 0.3135 shares of Phelps Dodge common stock for
each outstanding share of common stock of Cyprus Amax Minerals Company that is
validly tendered and not properly withdrawn. We are also making a separate offer
to exchange 0.4098 shares of Phelps Dodge common stock for each outstanding
share of common stock of ASARCO Incorporated.

     We have proposed a business combination of Phelps Dodge, Cyprus Amax and
Asarco, pursuant to which all outstanding Cyprus Amax shares and Asarco shares
would be exchanged for Phelps Dodge shares. We believe our proposed business
combination would be far more favorable to you and to Asarco shareholders than
the proposed two-party Asarco-Cyprus Amax merger announced in July 1999.
However, despite our repeated requests, the management and Boards of Directors
of Cyprus Amax and Asarco have been unwilling to meet with us to discuss our
proposed business combination. For this reason, we are making offers directly to
the shareholders of Cyprus Amax and Asarco to exchange their shares for Phelps
Dodge shares.

     Our obligation to exchange Phelps Dodge common stock for Cyprus Amax common
stock is subject to the conditions listed under "The Offer -- Conditions of Our
Offer." Our offer to Cyprus Amax shareholders is not, however, conditioned on
the success of our offer to Asarco shareholders, nor is our offer to Asarco
shareholders conditioned on the success of our offer to Cyprus Amax
shareholders.

     Phelps Dodge's common stock trades on the New York Stock Exchange under the
symbol "PD."

     SEE "RISK FACTORS" BEGINNING ON PAGE 6 FOR A DISCUSSION OF CERTAIN FACTORS
THAT YOU SHOULD CONSIDER IN CONNECTION WITH OUR OFFER.

     WE ARE NOT ASKING YOU FOR A PROXY AND YOU ARE REQUESTED NOT TO SEND US A
PROXY. Any solicitation of proxies will be made only pursuant to separate proxy
solicitation materials complying with the requirements of Section 14(a) of the
Securities Exchange Act of 1934.
                           -------------------------

     Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or passed upon the
adequacy or accuracy of this prospectus. Any representation to the contrary is a
criminal offense.
                           -------------------------

                      The Dealer Manager for the Offer is
                           MORGAN STANLEY DEAN WITTER
                           -------------------------

                The date of this prospectus is September 2, 1999
<PAGE>   2

                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                PAGE
                                                                ----
<S>                                                             <C>
QUESTIONS AND ANSWERS ABOUT THE PROPOSED COMBINATION........     iii
WHERE YOU CAN FIND MORE INFORMATION.........................       v
SUMMARY.....................................................       1
  The Proposed Combination..................................       1
  Reasons for the Proposed Combination......................       1
  The Offer.................................................       3
  The Companies.............................................       4
  Risk Factors..............................................       5
RISK FACTORS................................................       6
  Benefits of the Combination May Not Be Realized...........       6
  Fixed Exchange Ratio of Our Offer Could Work to Your
     Disadvantage...........................................       6
  Copper Price Volatility May Reduce Income.................       7
  Environmental and Regulatory Compliance May Impose
     Substantial Costs......................................       8
  Operations Outside the United States Are Subject to
     Risks..................................................      10
  Mining Is Subject to Risks................................      10
  Reserve Levels Are Subject To Uncertainty.................      11
  Year 2000 Poses Potential Risks...........................      11
THE PROPOSED COMBINATION....................................      13
REASONS FOR THE PROPOSED COMBINATION........................      14
BACKGROUND OF THE OFFER.....................................      16
THE OFFER...................................................      32
  Timing of Our Offer.......................................      33
  Litigation................................................      33
  Extension, Termination and Amendment......................      34
  Exchange of Cyprus Amax Shares; Delivery of Phelps Dodge
     Common Stock...........................................      35
  Cash Instead of Fractional Shares of Phelps Dodge Common
     Stock..................................................      35
  Withdrawal Rights.........................................      35
  Procedure for Tendering...................................      36
  Material U.S. Federal Income Tax Consequences.............      39
  Effect of Offer on Market for Cyprus Amax Shares;
     Registration Under the Exchange Act....................      40
  Purpose of Our Offer; the Phelps Dodge/Cyprus Amax
     Merger.................................................      41
  Conditions of Our Offer...................................      43
  Relationships with Cyprus Amax............................      46
  Fees and Expenses.........................................      46
  Accounting Treatment......................................      47
  Stock Exchange Listings...................................      47
THE COMPANIES...............................................      48
  Phelps Dodge Corporation..................................      48
  ASARCO Incorporated.......................................      48
  Cyprus Amax Minerals Company..............................      49
MARKET PRICES AND DIVIDENDS.................................      50
PHELPS DODGE CORPORATION SELECTED HISTORICAL FINANCIAL
  DATA......................................................      51
ASARCO INCORPORATED SELECTED HISTORICAL FINANCIAL DATA......      52
CYPRUS AMAX MINERALS COMPANY SELECTED HISTORICAL FINANCIAL
  DATA......................................................      54
PHELPS DODGE COMPARATIVE PER SHARE DATA.....................      56
</TABLE>


                                        i
<PAGE>   3

<TABLE>
<CAPTION>
                                                                PAGE
                                                                ----
<S>                                                             <C>
UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION..........      58
DESCRIPTION OF PHELPS DODGE CAPITAL STOCK...................      77
  Authorized Capital Stock..................................      77
  Phelps Dodge Common Stock.................................      77
  Phelps Dodge Preferred Stock..............................      77
  Transfer and Dividend Paying Agent and Registrar..........      77
COMPARISON OF RIGHTS OF HOLDERS OF PHELPS DODGE SHARES AND
  CYPRUS AMAX SHARES........................................      78
  Comparison of Charter and By-law Provisions...............      78
  Comparison of Certain Statutory Provisions................      84
ASARCO AND CYPRUS AMAX INFORMATION..........................      87
FORWARD-LOOKING INFORMATION.................................      87
LEGAL MATTERS...............................................      88
EXPERTS.....................................................      88
SCHEDULE A -- DIRECTORS AND EXECUTIVE OFFICERS..............     A-1
SCHEDULE B -- ADDITIONAL INFORMATION REGARDING PHELPS DODGE
  CORPORATION'S EXPLORATION AND MINING PROPERTIES...........     B-1
</TABLE>

     THIS PROSPECTUS INCORPORATES IMPORTANT BUSINESS AND FINANCIAL INFORMATION
ABOUT PHELPS DODGE THAT IS NOT INCLUDED IN OR DELIVERED WITH THE PROSPECTUS.
THAT INFORMATION IS AVAILABLE WITHOUT CHARGE TO YOU UPON WRITTEN OR ORAL
REQUEST. YOU MUST ADDRESS YOUR REQUEST TO CORPORATE SECRETARY, PHELPS DODGE
CORPORATION, 2600 NORTH CENTRAL AVENUE, PHOENIX, ARIZONA 85004-3014, TELEPHONE
(602) 234-8598. TO OBTAIN TIMELY DELIVERY, YOU MUST REQUEST THE INFORMATION NO
LATER THAN SEPTEMBER 24, 1999.

                                       ii
<PAGE>   4

              QUESTIONS AND ANSWERS ABOUT THE PROPOSED COMBINATION

Q:  WHAT IS PHELPS DODGE PROPOSING?

A:  We are proposing a three-way combination of Phelps Dodge, Cyprus Amax and
    Asarco, pursuant to which all outstanding Cyprus Amax common shares and
    Asarco common shares would be exchanged for Phelps Dodge shares. We are
    making our offer to you through our wholly owned subsidiary, CAV
    Corporation, which is a Delaware corporation.

Q:  WHAT WOULD I RECEIVE IN EXCHANGE FOR MY SHARES?

A:  We are offering 0.3135 Phelps Dodge shares for each Cyprus Amax common
    share. We are separately offering 0.4098 Phelps Dodge common shares for each
    Asarco common share. You will not receive any fractional Phelps Dodge
    shares. Instead, you will receive cash in an amount equal to the market
    value of any fractional Phelps Dodge shares you would otherwise have been
    entitled to receive.

Q:  WILL I BE TAXED ON THE PHELPS DODGE SHARES I RECEIVE?

A:  No. We expect the transaction to be tax-free to Cyprus Amax shareholders.

Q:  WHY IS PHELPS DODGE MAKING THIS OFFER?

A:  We made several requests to meet with Cyprus Amax and Asarco to discuss our
    proposal, but the management and boards of Cyprus Amax and Asarco have
    refused to meet with us. That's why we are making this offer directly to
    you, the shareholders.

Q:  WHY WON'T CYPRUS AMAX AND ASARCO MEET WITH YOU?

A:  We don't know. In July, Cyprus Amax and Asarco announced that they had
    agreed to combine. They told us they were not at liberty to have discussions
    with us because of their merger agreement. But they could amend or waive
    those provisions. We believe our proposed three-way combination is far more
    favorable to you than a two-way combination of Cyprus Amax and Asarco.

Q:  WHY IS YOUR THREE-WAY COMBINATION BETTER THAN THE PROPOSED CYPRUS
    AMAX-ASARCO MERGER?

A:  There are several reasons:

    - We're offering a substantial premium for your shares, which in effect
      represents an up-front payment to you for the cost savings we expect to
      achieve.

    - We plan to continue Phelps Dodge's $2.00 per share annual dividend, which
      means you would receive a dividend increase to 4.1 times the level planned
      under the proposed Asarco-Cyprus Amax merger.

    - We believe that under our leadership, we will be able to optimize the
      combined operations of the three companies and deliver superior returns on
      invested capital throughout the entire copper cycle. You would participate
      in the greater upside potential of the combined entity, through your
      ownership of Phelps Dodge shares.

Q:  WHAT ARE THE CONDITIONS TO YOUR OFFER?

A:  Our offer is subject to several conditions, including:

    - tender of at least a majority of Cyprus Amax's shares;

    - shareholders of Cyprus Amax not approving the Asarco/Cyprus Amax merger or
      the Asarco/Cyprus Amax merger agreement being otherwise terminated;

    - making Cyprus Amax's "poison pill" shareholder rights plan inapplicable to
      our offer;

    - Cyprus Amax's board having taken action so that Delaware's anti-takeover
      statute and the "Fair Price" provision of Cyprus Amax's charter are
      inapplicable to our offer;

    - our stockholders having approved the issuance of our stock pursuant to our
      offer; and

    - clearance under U.S. antitrust laws.

                                       iii
<PAGE>   5

     These conditions and other conditions to our offer are discussed in this
     prospectus under "The Offer -- Conditions of Our Offer."

Q:  HOW IS YOUR CYPRUS AMAX OFFER RELATED TO YOUR ASARCO OFFER?

A:  While we would prefer to combine all three companies, the two offers are
    separate, and neither is conditioned on the other.

Q:  HOW WOULD YOU GO ABOUT COMPLETING YOUR PROPOSED ACQUISITION?

A:  Once we acquire shares in the offer, we plan to have our wholly owned
    subsidiary CAV Corporation merge with Cyprus Amax, so that Cyprus Amax would
    become a wholly owned subsidiary of Phelps Dodge.

Q:  HOW LONG WILL IT TAKE TO COMPLETE YOUR PROPOSED COMBINATION?

A:  If Asarco and Cyprus Amax promptly cooperate, the combination could be
    completed early in the fourth quarter of this year. However, Asarco and
    Cyprus may try to delay our offer. We are firmly committed to our proposal,
    and intend to see it through. By tendering your shares, you will be sending
    a message to Cyprus Amax's management and board that you want Cyprus Amax to
    participate in a combination with Phelps Dodge.

Q:  WHERE CAN I FIND MORE INFORMATION ABOUT PHELPS DODGE, ASARCO AND CYPRUS
    AMAX?

A:  You can find more information about Phelps Dodge, Asarco and Cyprus Amax
    from various sources described under "Where You Can Find More Information"
    on page v.

Q:  HOW DO I PARTICIPATE IN YOUR OFFER?

A:  To tender your shares, you should do the following:

    - If you hold your shares in your own name, complete and sign the enclosed
      letter of transmittal and return it with your share certificates to
      ChaseMellon Shareholder Services, L.L.C., the exchange agent for the
      offer, at one of its addresses on the back cover of this prospectus.

    - If you hold your shares in "street name" through a broker, ask your broker
      to tender your shares.

Q:  WHAT SHOULD I DO IF I HAVE QUESTIONS?

A:  If you have any questions about our offer or the proposed combination of
    Phelps Dodge, Asarco and Cyprus Amax, please call our information agent,
    Innisfree M&A Incorporated, toll-free at 1-877-750-5838.

                                       iv
<PAGE>   6

                      WHERE YOU CAN FIND MORE INFORMATION

     Phelps Dodge, Asarco and Cyprus Amax file annual, quarterly and special
reports, proxy statements and other information with the Securities and Exchange
Commission (the SEC). You may read and copy any reports, statements or other
information we file at the SEC's public reference room at 450 Fifth Street,
N.W., Washington, D.C. 20549, or at the SEC's public reference rooms in New
York, New York and Chicago, Illinois. Please call the SEC at 1-800-SEC-0330 for
further information on the public reference rooms. Our SEC filings are also
available to the public from commercial document retrieval services and at the
Internet world wide web site maintained by the SEC at www.sec.gov. Phelps Dodge
filed a registration statement on Form S-4 to register with the SEC the Phelps
Dodge common shares to be issued pursuant to our offer. This prospectus is a
part of that registration statement. As allowed by SEC rules, this prospectus
does not contain all the information you can find in the registration statement
or the exhibits to the registration statement.

     Before we commence our offer, we will file with the SEC a statement on
Schedule 14D-1 pursuant to rule 14d-3 under the Securities Exchange Act of 1934
furnishing certain information about our offer. You may read and copy the
Schedule 14D-1 (and any amendments to it) at the SEC's public reference room in
Washington, D.C. referred to above.

     The SEC allows us to "incorporate by reference" information into this
prospectus, which means that we can disclose important information to you by
referring you to another document filed separately with the SEC. The information
incorporated by reference is deemed to be part of this prospectus, except for
any information superseded by information contained directly in this prospectus.
This prospectus incorporates by reference the documents set forth below that
Phelps Dodge, Asarco or Cyprus Amax have previously filed with the SEC. These
documents contain important information about Phelps Dodge, Asarco and Cyprus
Amax and their financial condition.

     DOCUMENTS INCORPORATED BY REFERENCE ARE AVAILABLE WITHOUT CHARGE UPON
REQUEST TO: CORPORATE SECRETARY, PHELPS DODGE CORPORATION, 2600 NORTH CENTRAL
AVENUE, PHOENIX, AZ 85004-3014, TELEPHONE (602) 234-8598. IN ORDER TO ENSURE
TIMELY DELIVERY, ANY REQUEST FOR DOCUMENTS SHOULD BE SUBMITTED NO LATER THAN
SEPTEMBER 24, 1999.

          The following documents filed with the SEC by Phelps Dodge are
     incorporated herein by reference:

          (i) Phelps Dodge's Annual Report on Form 10-K for the year ended
     December 31, 1998 (revised information regarding Phelps Dodge's exploration
     and mining properties is set forth in Schedule B to this prospectus);

          (ii) Phelps Dodge's Proxy Statement for the Annual Meeting of
     Stockholders held on May 5, 1999;

          (iii) Phelps Dodge's Quarterly Reports on Form 10-Q for the periods
     ended March 31, 1999 and June 30, 1999;

          (iv) Phelps Dodge's Annual Report on Form 11-K for the fiscal year
     ended December 31, 1998; and

          (v) Phelps Dodge's Current Reports on Form 8-K dated August 23, 1999
     and August 26, 1999.

     The following documents filed with the SEC by Asarco are incorporated
herein by reference:

          (i) Asarco's Annual Report on Form 10-K for the year ended December
     31, 1998 (except for the
report of Asarco's independent accountants contained therein which is not
incorporated herein by reference because the consent of Asarco's independent
accountants has not yet been obtained);

          (ii) Asarco's Proxy Statement for the Annual Meeting of Shareholders
     held on April 28, 1999;

          (iii) Asarco's Quarterly Reports on Form 10-Q for the periods ended
     March 31, 1999 and June 30, 1999; and

          (iv) Asarco's Current Report on Form 8-K dated July 20, 1999.

                                        v
<PAGE>   7

     The following documents filed with the SEC by Cyprus Amax are incorporated
herein by reference:

          (i) Cyprus Amax's Annual Report on Form 10-K for the year ended
     December 31, 1998 (except for the report of Cyprus Amax's independent
     accountants contained therein which is not incorporated herein by reference
     because the consent of Cyprus Amax's independent accountants has not yet
     been obtained);

          (ii) Cyprus Amax's Proxy Statement for the Annual Meeting of
     Shareholders held on May 6, 1999;

          (iii) Cyprus Amax's Quarterly Reports on Form 10-Q for the periods
     ended March 31, 1999 and June 30, 1999; and

          (iv) Cyprus Amax's Current Reports on Form 8-K dated July 21, 1999,
     July 14, 1999 and February 24, 1999.

     All documents filed by Phelps Dodge, Asarco or Cyprus Amax pursuant to
Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 from
the date of this prospectus to the date that shares are accepted for exchange
pursuant to our offer (or the date that our offer is terminated) shall also be
deemed to be incorporated herein by reference.

                                       vi
<PAGE>   8

                                    SUMMARY

     This summary highlights selected information from this prospectus, and may
not contain all of the information that is important to you. To better
understand the proposed Phelps Dodge/Asarco/Cyprus Amax combination and our
separate offers to the shareholders of Asarco and Cyprus Amax, you should read
this entire document carefully, as well as those additional documents to which
we refer you. See "Where You Can Find More Information" on page v.

                            THE PROPOSED COMBINATION

     We are proposing a three-way business combination of Phelps Dodge
Corporation (Phelps Dodge), ASARCO Incorporated (Asarco) and Cyprus Amax
Minerals Company (Cyprus Amax). We are offering to exchange all of the
outstanding Cyprus Amax common shares for Phelps Dodge common shares at an
exchange ratio of 0.3135 Phelps Dodge common shares for each Cyprus Amax common
share. We are also separately offering to exchange all of the outstanding Asarco
common shares for Phelps Dodge common shares at an exchange ratio of 0.4098
Phelps Dodge common shares for each Asarco common share.

     In July 1999, Asarco and Cyprus Amax announced that they had agreed to
combine their companies. We believe our proposed three-way business combination
is much more valuable to shareholders of Asarco and Cyprus Amax than the
proposed two-party Asarco-Cyprus Amax merger, based on:

     - the sizeable premium we are offering which, in effect, represents an
       up-front payment to you for the substantial cost savings we expect to
       achieve;

     - our plan to continue Phelps Dodge's current $2.00 per share dividend,
       resulting in a substantial dividend increase for Asarco and Cyprus Amax
       shareholders to more than quadruple the level contemplated in the
       proposed Asarco-Cyprus Amax merger; and

     - your opportunity to participate in the greater upside potential of the
       combined company through the ownership of Phelps Dodge common stock.

     However, despite our repeated requests, the management and Boards of
Directors of Asarco and Cyprus Amax have been unwilling to meet with us to
discuss our proposed business combination. For this reason, we are making these
offers directly to the shareholders of Asarco and Cyprus Amax. See "Background
of the Offer" beginning on page 16.

     We would prefer to combine all three companies. However, our offer to
Cyprus Amax shareholders is not conditioned on the success of our offer to
Asarco shareholders, nor is our offer to Asarco shareholders conditioned on the
success of our offer to Cyprus Amax shareholders. See "The Offer" beginning on
page 32.

                      REASONS FOR THE PROPOSED COMBINATION

     We believe that our proposed combination of Phelps Dodge, Asarco and Cyprus
Amax presents a unique opportunity to create a large, resource-rich portfolio of
lower-cost global copper assets with enhanced flexibility to deliver superior
results in all business cycles. In addition to the substantial dividend increase
for Asarco and Cyprus Amax shareholders, we believe that the combination of
Phelps Dodge, Asarco and Cyprus Amax will produce the following benefits:

     - Substantial premium.  The exchange ratios we are offering imply
       significant premiums for Cyprus Amax and Asarco shareholders based on
       market prices of Phelps Dodge, Cyprus Amax and Asarco common stock before
       our proposal was first publicly announced.

     -  Accretion to cash flow and earnings.  The combination would result in
        immediate and substantial accretion to the cash flow of the combined
        company. We expect the combination to result in significant accretion to
        earnings per share of the combined company beginning in the second year
        after closing, assuming copper prices of $0.80 -- $0.85 per pound in
        2001.

                                        1
<PAGE>   9

     - Ability to integrate operations.  We expect the combined company to have
       significantly greater ability to integrate southwest U.S. mining
       operations, administrative functions in the U.S., Chile and Peru, and
       worldwide exploration and development activities.

     - Management strength.  The combined company would have a strong and deep
       management team, at both the operating and corporate levels, with strong
       credibility in the marketplace.

     -  Cost savings.  We expect to achieve annual cash cost savings of at least
        $200 million by the end of the second year after closing, as a result of
        reductions in overhead, purchasing, exploration and other expenses. We
        also expect at least another $65 million in annual savings from lower
        depreciation expenses, bringing the total annual savings to at least
        $265 million. These cost savings are based on public information and our
        expectation that we can deliver at least $75 million in incremental
        savings above the cash synergy figure of $125 million projected in the
        proposed Asarco-Cyprus Amax merger. This does not include any cost
        savings from the rationalization of high-cost production during periods
        of low copper prices.

     -  Operating leverage.  The combined company would have tremendous
        operating leverage, together with enough diversity in other businesses
        to mitigate cyclical downturns.

     -  Superior production capability.  The total annual copper production of
        the combined company would be approximately 3.8 billion pounds at
        current levels, with total attributable copper reserves of approximately
        80 billion recoverable pounds.

     - Increased competitiveness.  The combined company would have increased
       ability to compete for world-class projects.

     - Reduced capital expenditures.  By combining their businesses, Phelps
       Dodge, Asarco and Cyprus Amax would be able to reduce capital
       expenditures.

     -  Financial strength.  The company would have a strong, liquid balance
        sheet, with excellent access to capital.

See "Reasons for the Proposed Combination" beginning on page 14.

                                        2
<PAGE>   10

                                   THE OFFER

SUMMARY OF THE OFFER

     We are offering, upon the terms and subject to the conditions set forth in
this prospectus and in the related letter of transmittal, to exchange 0.3135
shares of Phelps Dodge common stock for each outstanding share of common stock
of Cyprus Amax that is validly tendered on or prior to the expiration date and
not properly withdrawn. We are making our offer through our wholly owned
subsidiary, CAV Corporation, which is a Delaware corporation. The term
"expiration date" means 12:00 midnight, New York City time, on October 1, 1999,
unless we extend the period of time for which this offer is open, in which case
the term "expiration date" means the latest time and date on which the offer, as
so extended, expires. We are also making a separate offer to exchange 0.4098
shares of Phelps Dodge common stock for each outstanding share of common stock
of Asarco.

CONDITIONS OF THE OFFER

     Our obligation to exchange shares of Phelps Dodge common stock for Cyprus
Amax shares pursuant to the offer is subject to several conditions referred to
below under "The Offer -- Conditions of Our Offer," including conditions as to
the minimum number of shares tendered, making Cyprus Amax's shareholder rights
plan, the "Fair Price" provisions in Cyprus Amax's charter and Delaware's
anti-takeover statute inapplicable to our offer, approval by our stockholders,
U.S. antitrust clearance, and other conditions that are discussed below.

TIMING OF THE OFFER

     Our offer is currently scheduled to expire on October 1, 1999; however, we
currently intend to extend our offer from time to time as necessary until all
the conditions to the offer have been satisfied or waived. See "The
Offer -- Extension, Termination and Amendment."

EXTENSION, TERMINATION AND AMENDMENT

     We expressly reserve the right, in our sole discretion, at any time or from
time to time, to extend the period of time during which our offer remains open,
and we can do so by giving oral or written notice of such extension to the
exchange agent. If we decide to extend our offer, we will make an announcement
to that effect no later than 9:00 A.M., New York City time, on the next business
day after the previously scheduled expiration date. We are not making any
assurance that we will exercise our right to extend our offer, although we
currently intend to do so until all conditions have been satisfied or waived.
During any such extension, all Cyprus Amax shares previously tendered and not
withdrawn will remain subject to the offer, subject to your right to withdraw
your Cyprus Amax shares.

     Subject to the SEC's applicable rules and regulations, we also reserve the
right, in our sole discretion, at any time or from time to time, (a) to delay
our acceptance for exchange or our exchange of any Cyprus Amax shares pursuant
to our offer, regardless of whether we previously accepted Cyprus Amax shares
for exchange, or to terminate our offer and not accept for exchange or exchange
any Cyprus Amax shares not previously accepted for exchange or exchanged, upon
the failure of any of the conditions of the offer to be satisfied and (b) to
waive any condition (other than the condition relating to the Phelps Dodge
stockholder approval, the condition relating to U.S. antitrust clearance, the
condition relating to the effectiveness of the registration statement for the
Phelps Dodge shares to be issued in our offer and, following Phelps Dodge
Stockholder approval, receipt of the legal opinion referred to below) or
otherwise to amend the offer in any respect, by giving oral or written notice of
such delay, termination or amendment to the exchange agent and by making a
public announcement. We will follow any extension, termination, amendment or
delay, as promptly as practicable, with a public announcement. In the case of an
extension, any such announcement will be issued no later than 9:00 A.M., New
York City time, on the next business day after the previously scheduled
expiration date. Subject to applicable law (including Rules 14d-4(c) and
14d-6(d) under the Securities Exchange Act of 1934, which require that any
material change in the information published, sent or given to the stockholders
in connection with the offer be promptly sent to stockholders in a manner
reasonably
                                        3
<PAGE>   11

designed to inform stockholders of such change) and without limiting the manner
in which we may choose to make any public announcement, we assume no obligation
to publish, advertise or otherwise communicate any such public announcement
other than by making a release to the Dow Jones News Service.

EXCHANGE AND SHARES; DELIVERY OF PHELPS DODGE COMMON STOCK

     Upon the terms and subject to the conditions of our offer (including, if
our offer is extended or amended, the terms and conditions of any such extension
or amendment), Phelps Dodge will accept for exchange, and will exchange, shares
validly tendered and not properly withdrawn as promptly as practicable after the
expiration date.

WITHDRAWAL RIGHTS

     Your tender of Cyprus Amax shares pursuant to the offer is irrevocable,
except that Cyprus Amax shares tendered pursuant to the offer may be withdrawn
at any time prior to the expiration date, and, unless we previously accepted
them pursuant to the offer, may also be withdrawn at any time after November 2,
1999.

PROCEDURE FOR TENDERING SHARES

     For you to validly tender Cyprus Amax shares pursuant to our offer, (a) a
properly completed and duly executed letter of transmittal (or manually executed
facsimile of that document), along with any required signature guarantees, or an
agent's message, which is explained below, in connection with a book-entry
transfer, and any other required documents, must be transmitted to and received
by the exchange agent at one of its addresses set forth on the back cover of
this prospectus, and certificates for tendered Cyprus Amax shares must be
received by the exchange agent at such address or those Cyprus Amax shares must
be tendered pursuant to the procedures for book-entry tender set forth in "The
Offer" (and a confirmation of receipt of such tender received), in each case
before the expiration date, or (b) you must comply with the guaranteed delivery
procedures set forth in "The Offer."

                                 THE COMPANIES

PHELPS DODGE CORPORATION
2600 North Central Avenue
Phoenix, AZ 85004-3014
(602) 234-8100

     Phelps Dodge Corporation is among the world's largest producers of copper,
carbon black and magnet wire, and is the world's largest producer of
continuous-cast copper rod. Phelps Dodge comprises two divisions:

     - Phelps Dodge Mining Company, which includes our worldwide copper
       operations and worldwide mineral exploration and development programs;
       and

     - Phelps Dodge Industries, which includes our specialty chemicals segment
       and our wire and cable segment.

     As of June 30, 1999, Phelps Dodge and its subsidiaries had 13,193
employees.

ASARCO INCORPORATED
180 Maiden Lane
New York, NY 10038
(212) 510-2000

     Asarco Incorporated, a New Jersey corporation organized in 1899, is one of
the world's leading producers of copper. Asarco also produces specialty
chemicals and aggregates. Asarco's copper business includes integrated mining,
smelting and refining operations in North America and in Peru through its 54.3%
owned subsidiary, Southern Peru Copper Corporation. Enthone-OMI, Inc., a wholly
owned subsidiary, operates a

                                        4
<PAGE>   12

worldwide specialty chemicals business focused on functional and decorative
coatings for the electronics and metal finishing industries. American Limestone
Company, a wholly owned subsidiary, produces construction aggregates,
ready-mixed concrete and agricultural limestone. Asarco also operates a custom
lead smelting business, a zinc mining business and a specialty metals business.
Asarco owns Encycle, Inc., which operates a waste recycling facility and
Hydrometrics, an environmental consulting and construction firm. As of June 30,
1999, Asarco and its subsidiaries employed approximately 10,100 employees.

CYPRUS AMAX MINERALS COMPANY
9100 East Mineral Circle
Englewood, CO 80112
(303) 643-5000

     Cyprus Amax Minerals Company, a Delaware corporation, is a major mining
company engaged, directly or through its subsidiaries and affiliates, in the
exploration for and extraction, processing, and marketing of mineral resources.
Cyprus Amax is a leading copper producer, the world's largest producer of
molybdenum and has a significant position in gold via its 30% interest in
Kinross Gold Corporation. Cyprus Amax sold certain eastern and midwestern coal
operations in June of 1998 and sold its lithium business in October of 1998.
Cyprus Amax sold its remaining U.S. coal operations in June 1999. Cyprus Amax
still holds its Australian coal properties. As of June 30, 1999, Cyprus Amax and
its subsidiaries employed approximately 4,600 employees.

                                  RISK FACTORS

     In deciding whether to tender your shares pursuant to our offer, you should
read carefully this prospectus and the documents to which we refer you. You
should also carefully consider the following factors:

     - the risks associated with integrating Asarco and Cyprus Amax into our
       company, including the risk that the amount and timing of the cost
       savings and other expected benefits from the business combination may be
       different from what we expect;

     - the fixed exchange ratio of our offer, which may work to your
       disadvantage if Cyprus Amax stock increases in value or Phelps Dodge
       stock decreases in value;

     - the fact that we may not be able to complete business combinations with
       both Asarco and Cyprus Amax, which would reduce the expected cost savings
       and other benefits, and would likely cause additional transaction
       expenses;

     - the volatility of copper prices;

     - the extensive governmental regulations, including regulations relating to
       environmental matters, to which Phelps Dodge, Asarco and Cyprus Amax are
       subject;

     - the risks associated with conducting operations outside the United
       States, especially in less developed countries;

     - the risks associated with mining;

     - the fact that reserve levels are subject to uncertainties; and

     - potential risks associated with the Year 2000.

See "Risk Factors" beginning on the following page for a more complete
discussion of these factors.

                                        5
<PAGE>   13

                                  RISK FACTORS

     In deciding whether to tender your shares pursuant to our offer, you should
read carefully this prospectus and the documents to which we refer you. You
should also carefully consider the following factors:

BENEFITS OF THE COMBINATION MAY NOT BE REALIZED

     If we complete the proposed Phelps Dodge/Asarco/Cyprus Amax business
combination, we will integrate three companies that have previously operated
independently. This will involve integrating:

     -  corporate headquarters and mining administration offices;

     -  worldwide exploration and development activities;

     -  mining operations, particularly in the southwestern United States; and

     -  administrative functions in the U.S., Chile and Peru.

We may not be able to integrate the operations of Asarco and Cyprus Amax without
encountering difficulties. The diversion of the attention of management to the
integration effort and any difficulties encountered in combining operations
could adversely affect the combined company's businesses. Although we expect at
least $200 million in annual cash cost savings from the combination by the end
of the second year (excluding any savings from rationalizations of high-cost
production during periods of low copper prices), together with $65 million in
annual savings from lower depreciation expenses, we cannot be sure that we will
be able to achieve them in the amounts expected or as quickly as we now expect.
Actual cost savings may be higher or lower than we currently expect, and may
take a longer or shorter time to achieve than we currently expect. Our estimates
concerning the amount and timing of cost savings have been developed by our
management and reflect our best judgment based on publicly available information
about Asarco and Cyprus Amax.

     More generally, our views about the expected benefits of our proposed
combination are based on publicly available information about Asarco and Cyprus
Amax. Those companies may have other information, not available to us, that
would significantly affect our estimates or views.

     Because our offers to acquire Asarco and Cyprus Amax are separate, and
neither offer is dependent on the success of the other, it is possible that one
of the following scenarios will occur:

     -  we will acquire Asarco, but not Cyprus Amax;

     -  we will acquire Cyprus Amax, but not Asarco; or

     -  we will acquire both Asarco and Cyprus Amax, but it will take us much
        longer to acquire one company than the other.

In any of these cases, the cost savings we expect from the combination will be
less than if all three companies combined promptly. If we acquire only one of
Asarco or Cyprus Amax, we may still encounter difficulties in integrating its
operations, and may not be able to achieve the cost savings we expect in the
amounts or time periods anticipated. In addition, under the terms of the July
15, 1999 merger agreement between Asarco and Cyprus Amax, Asarco or Cyprus Amax
would be required to pay a $45 million fee to the other party if, after its
shareholders voted against the Asarco/Cyprus Amax merger, it terminated the
agreement in order to enter into a business combination with Phelps Dodge. This
fee would not be payable, however, if shareholders of both Asarco and Cyprus
Amax vote not to approve that transaction.

FIXED EXCHANGE RATIO OF OUR OFFER COULD WORK TO YOUR DISADVANTAGE

     We are offering to exchange shares of Phelps Dodge common stock for shares
of Cyprus Amax common stock at a fixed ratio of 0.3135 shares of Phelps Dodge
common stock for each share of Cyprus Amax common stock. Once you have tendered
your stock and your withdrawal rights have expired, you will be locked into that
exchange ratio, you will not be able to capture gains from possible increases in
value of Cyprus Amax common

                                        6
<PAGE>   14

stock, and, while you may benefit from possible increases in value of Phelps
Dodge common stock, you may incur losses from possible decreases in value of
Phelps Dodge common stock.

COPPER PRICE VOLATILITY MAY REDUCE INCOME

     Copper is an internationally traded commodity. Its prices are effectively
determined on the two major metals exchanges -- New York Mercantile Exchange
(COMEX) and London Metal Exchange (LME). The prices on these exchanges reflect
the worldwide balance of copper demand and supply and various domestic and
international macroeconomic and political conditions. Prices are also sometimes
influenced significantly by numerous other factors, including speculative
actions, the availability and cost of substitute materials, and currency
exchange fluctuations. The copper market is volatile and cyclical, as
illustrated by the following chart showing the high, low and average COMEX spot
price per pound of copper cathode for the years indicated:

<TABLE>
<CAPTION>
YEAR                                                HIGH      LOW      AVERAGE
- ----                                               ------    ------    -------
<S>                                                <C>       <C>       <C>
1989...........................................    $ 1.55    $ 1.03    $ 1.27
1990...........................................      1.38      0.96      1.19
1991...........................................      1.20      0.96      1.05
1992...........................................      1.16      0.93      1.03
1993...........................................      1.07      0.72      0.85
1994...........................................      1.40      0.78      1.07
1995...........................................      1.46      1.21      1.35
1996...........................................      1.31      0.86      1.06
1997...........................................      1.23      0.76      1.04
1998...........................................      0.86      0.64      0.75
1999 (through August 31).......................      0.79      0.61      0.68
</TABLE>

- ---------------

SOURCE:  COMEX

On August 31, 1999, the closing spot price of copper cathode on the COMEX was
$0.78 per pound.

     Any material change in the price we receive for copper, or in our unit
production costs, has a significant effect on our results. Our share of current
annual production is approximately 1.6 billion pounds of copper. Accordingly,
each 1 cent per pound change in the average annual copper price, or in average
annual unit production costs, causes a variation in annual operating income
before taxes of approximately $16 million. Following the completion of our
proposed Phelps Dodge/Asarco/Cyprus Amax combination, the combined company's
annual production would be approximately 3.8 billion pounds, based on current
levels. We estimate that each 1 cent per pound change in the average annual
copper price, or in average unit production costs, would cause a variation in
annual operating income before taxes of approximately $38 million at these
production levels.

     If we combined with Cyprus Amax but not with Asarco, our combined annual
production would be approximately 2.8 billion pounds, based on current levels.
We estimate that each 1 cent per pound change in the average annual copper
price, or in average unit production costs, would cause a variation in annual
operating income before taxes of approximately $28 million at these production
levels.

     While Phelps Dodge, Asarco and Cyprus Amax historically have used limited
financial risk management techniques to reduce a portion of their exposure to
the volatility of commodity market prices, there can be no assurance that the
combined company will continue to be able to do so effectively in the future. In
addition, depending upon the specific techniques employed, market conditions and
other factors, these activities could reduce the earnings or cash flow that the
combined company otherwise would realize or could result in losses.

     Cyprus Amax is the world's largest producer of molybdenum, which, like
copper, is characterized by volatile and cyclical prices. Molybdenum consumption
depends heavily on worldwide demand from the specialty steel industry and, to a
lesser extent, on chemical applications. World molybdenum consumption remained
at record levels in the first half of 1998, continuing the growth trend begun in
1994. Beginning in the

                                        7
<PAGE>   15

second half of 1998, molybdenum consumption declined as a result of the economic
downturn in Asia. Overall 1998 molybdenum worldwide consumption declined an
estimated four percent primarily in metallurgical applications. The molybdenum
market remained oversupplied during the second half of 1998, and production
curtailments were announced in China and at three primary mines in North America
during the fourth quarter. The molybdenum market continued to be oversupplied in
the first half of 1999. Western World metallurgical grade molybdenum dealer
oxide prices averaged about $2.65 per pound in the first half of 1999 compared
with full-year averages of about $3.40 per pound in 1998 and about $4.30 per
pound in 1997. Cyprus Amax molybdenum realizations averaged $4.11 per pound in
the first half of 1999 compared with full-year averages of $4.95 per pound in
1998 and $5.50 per pound in 1997, with realizations positively impacted by
higher-valued molybdenum chemical products. A substantial portion of world
molybdenum production is a by-product of copper mining, which is relatively
insensitive to molybdenum price levels. Exports to the Western World, especially
from China, can also influence competitive conditions.

ENVIRONMENTAL AND REGULATORY COMPLIANCE MAY IMPOSE SUBSTANTIAL COSTS

     The mining operations and exploration activities of Phelps Dodge, Asarco
and Cyprus Amax, both inside and outside the United States, are subject to
extensive laws and regulations governing prospecting, developing, production,
exports, taxes, labor standards, occupational health, waste disposal, protection
and remediation of the environment, protection of endangered and protected
species, mine safety, toxic substances and other matters. Mining is also subject
to risks and liabilities associated with pollution of the environment and the
disposal of waste products occurring as a result of mineral exploration and
production. Compliance with these laws and regulations could impose substantial
costs and subject the combined company to significant potential liabilities.

  ENVIRONMENTAL MATTERS

     Our operations in the United States are subject to stringent federal, state
and local laws and regulations relating to improving or maintaining
environmental quality. Our global operations are also subject to many
environmental protection laws. Environmental laws often require parties to pay
for remedial action or to pay damages regardless of fault. Environmental laws
also often impose liability with respect to divested or terminated operations,
even if the operations were terminated or divested many years ago. The federal
Clean Air Act has had a significant impact, particularly on our smelters. Costs
associated with environmental compliance have increased over time, and we expect
these costs to continue to rise in the future.

     We are subject to the Comprehensive Environmental Response, Compensation
and Liability Act (CERCLA or Superfund), as amended by the Superfund Amendments
and Reauthorization Act of 1986. Under Superfund, the Environmental Protection
Agency (EPA) has identified on its CERCLIS database approximately 35,000 sites
throughout the United States for review, ranking and possible inclusion on the
National Priorities List (NPL). The EPA has included 13 sites owned by us on the
CERCLIS database. Even though we believe that most, if not all, of the sites
identified do not qualify for listing on the NPL, we may be required to remove
hazardous waste or remediate the alleged effects of hazardous substances on the
environment. In many cases, this involves past disposal practices at sites not
owned by us. We have received notice that we are a potentially responsible party
from the EPA or individual states under CERCLA or an equivalent state law. We
are participating in environmental assessment and remediation activity at 39
sites.

     At December 31, 1998, we had reserves of $106.0 million for remediation of
some of the sites discussed above and other environmental costs. We record
liabilities for environmental expenditures when it is probable that obligations
have been incurred and the costs can be reasonably estimated. The amounts of
these liabilities are very difficult to estimate. This is due to factors such as
the unknown extent of the remedial actions that may be required. In the case of
sites not owned by us, the extent of our probable liability in proportion to the
probable liability of other parties is difficult to estimate. We have other
possible environmental liabilities that in our judgment cannot be reasonably
estimated. Losses attributable to remediation costs are reasonably possible at
other sites. Based on the information available to us, the accruals, both
individually and in the aggregate, from known environmental liabilities are not
expected to result in a material additional loss beyond that already accrued. We
cannot currently estimate the total additional loss we may incur for
environmental
                                        8
<PAGE>   16

liabilities resulting from such things as frequently changing environmental
laws, regulations or agency interpretations, which are beyond our control, but
that loss could be potentially material.

     The U.S. and non-U.S. operations of Asarco and Cyprus Amax are also subject
to stringent environmental laws, including CERCLA. The following excerpts are
from Asarco's quarterly report on Form 10-Q for the period ended June 30, 1999:

          Reserves for closed plants and environmental matters, including mine
     reclamation costs for active and closed properties, totaled $123.8 million
     at June 30, 1999. Asarco anticipates that expenditures relating to these
     reserves will be made over the next several years. Net cash expenditures
     against these reserves for the three months ended June 30, 1999 and 1998
     were $12.6 million and $25.4 million, respectively. Expenditures for the
     six months ended June 30, 1999 and 1998 were $25.6 million and $40.2
     million, respectively.

                                     . . .

          Asarco and certain of its subsidiaries have received notices from EPA
     and other federal and state agencies that they and in most cases numerous
     other parties are potentially responsible to remediate alleged hazardous
     substance releases at certain sites under CERCLA or similar state laws. In
     addition, Asarco and certain of its subsidiaries are defendants in lawsuits
     brought under CERCLA or state laws that seek substantial damages and
     remediation. Remedial action is being undertaken by Asarco at some of the
     sites.

The following excerpt is from Cyprus Amax's quarterly report on Form 10-Q for
the period ended June 30, 1999:

          At June 30, 1999, Cyprus Amax had accruals of approximately $252
     million for expected future mine closure, reclamation, and environmental
     remediation liabilities. Total reclamation costs for Cyprus Amax at the end
     of current mine lives are estimated at about $253 million of which
     approximately $110 million was reserved at June 30, 1999. Additionally, the
     cost range of reasonably possible outcomes for sites where remediation
     costs are estimable is from $120 million to $450 million, of which
     approximately $142 million was accrued at June 30, 1999. Work on these
     sites is expected to be substantially completed in the next several years,
     subject to the inherent delays involved in the process. Remediation costs
     that could not be reasonably estimated at June 30, 1999, are not expected
     to have a material impact on the financial condition and ongoing operations
     of Cyprus Amax.

  OTHER REGULATORY MATTERS

     In recent years, the U.S. Congress has considered a number of proposed
amendments to the General Mining Law of 1872 which governs mining claims and
related activities on federal lands. Although Congress has not adopted any such
legislation, it could do so in the future. If ever adopted, such legislation
could impose royalties on minerals extracted from federal lands, require payment
of fair market value for patenting federal lands, and required that patented
lands used for non-mining purposes revert to the federal government. Passage of
mining law amendments or revisions to the hardrock mining surface management
regulations could result in additional expenses in the development and operation
of new mines on federal lands.

     Phelps Dodge, Asarco and Cyprus Amax are also subject to federal and state
laws and regulations pertaining to plant and mine safety and health conditions.
These laws include the Occupational Safety and Health Act of 1970 and the Mine
Safety and Health Act of 1977. Present and proposed regulations govern worker
exposure to a number of substances and conditions present in work environments.
These include dust, mist, fumes, heat and noise. Compliance with these
regulations may require significant expenditures.

     The global operations of Phelps Dodge, Asarco and Cyprus Amax are also
subject to extensive laws and regulations governing mining operations and
exploration, including laws and regulations pertaining to plant and mine safety
and health conditions. These laws and regulations may impose substantial costs
on our operations outside the United States.

                                        9
<PAGE>   17

  PRODUCT AND PERSONAL INJURY LITIGATION

     Asarco may also be subject to risks from product liability and personal
injury lawsuits. The following excerpt is from Asarco's quarterly report on Form
10-Q for the period ended June 30, 1999:

          Asarco and two subsidiaries, as of June 30, 1999, are defendants in
     1,169 lawsuits brought by 5,221 primary and 924 secondary plaintiffs
     seeking substantial actual and punitive damages for personal injury or
     death allegedly caused by exposure to asbestos. Three of these lawsuits are
     purported class actions, two of which are allegedly brought on behalf of
     persons who are not known to have asbestos-related injury. The third is
     purportedly brought on behalf of persons suing both tobacco-related and
     asbestos-related entities claiming damages for personal injury or death
     arising from exposure to asbestos and cigarette smoke. In addition, Asarco
     and certain subsidiaries are defendants in product liability lawsuits
     involving various other products, including metals.

OPERATIONS OUTSIDE THE UNITED STATES ARE SUBJECT TO RISKS

     We are a global company with substantial operations outside the United
States, including in Latin America, Asia and Europe. Both Asarco and Cyprus Amax
also have significant operations located in countries outside the United States,
including Chile, Peru and throughout Europe, Asia and Australia.

     Mining and other investments outside the United States are subject to the
risks normally associated with conducting business in non-U.S. countries,
particularly those that are less developed or have emerging economies:

     - uncertain political and economic environments;

     - risks of war and civil disturbances;

     - government restrictions on the movement of funds;

     - government actions to deprive us of our contract rights or to take our
       property without fair compensation;

     - adverse changes in laws or policies of particular countries;

     - increases in foreign taxation;

     - delays in obtaining or the inability to obtain necessary governmental
       permits;

     - limitations on ownership and on repatriation of earnings; and

     - foreign exchange controls and currency fluctuations.

     Although we are not currently experiencing any significant problems in
non-U.S. countries arising from these risks, problems could arise in the future.
Investments made by Phelps Dodge, Asarco and Cyprus Amax outside the U.S. may
also be adversely affected by U.S. government laws and policies affecting
foreign trade, investment and taxation.

MINING IS SUBJECT TO RISKS

     The business of mining is subject to a number of risks and hazards,
including:

     - environmental hazards;

     - labor disputes;

     - encountering unusual or unexpected geologic formations or other
       geological or grade problems;

     - metallurgical and other processing problems;

     - encountering unanticipated ground or water conditions;

     - cave-ins, pit-wall failures and rock falls; and

                                       10
<PAGE>   18

     - periodic interruptions due to inclement or hazardous weather conditions
       or other unfavorable operating conditions.

     In addition to the foregoing items, in the case of development projects,
the economic feasibility of any individual project is based upon, among other
things:

     - the interpretation of geological data obtained from drill holes and other
       sampling techniques;

     - feasibility studies, which derive estimates of cash operating costs based
       upon anticipated tonnage and grade of ore to be mined and processed;

     - the configuration of the ore body;

     - expected recovery rates of metals from the ore;

     - comparable facility and equipment costs;

     - environmental and regulatory requirements;

     - anticipated climatic conditions; and

     - estimates of labor productivity.

     Such development projects also are subject to the successful completion of
final feasibility studies, issuance of necessary permits, and receipt of
adequate financing. Accordingly, uncertainties related to development projects
are more significant than those pertaining to existing operations.

     The risks associated with mining described above could cause personal
injury or death, environmental damage, delays in mining, monetary losses and
possible legal liability. These risks could also cause mining projects to be
more expensive to develop or operate than expected, or to produce less than
expected, and could result in damage to mines or producing facilities.

RESERVE LEVELS ARE SUBJECT TO UNCERTAINTY

     There are a number of uncertainties inherent in estimating quantities of
reserves, including many factors beyond the control of Phelps Dodge, Asarco and
Cyprus Amax. The reserve data incorporated by reference in this prospectus are
in large part only estimates. We cannot assure you that the volume and grade of
reserves recovered and rates of production will not be less than anticipated.
Declines in the market price of a particular metal also may render reserves
containing relatively lower grades of mineralization uneconomic to exploit. If
the price we realized for a particular commodity were to decline substantially
below the price at which ore reserves were calculated for a sustained period of
time, we potentially could experience reductions in reserves and asset
write-downs. Under certain such circumstances, we may discontinue the
development of a project or mining at one or more properties. Further, changes
in operating and capital costs and other factors, including but not limited to
short-term operating factors such as the need for sequential development of ore
bodies and the processing of new or different ore grades, may materially and
adversely affect reserves.

YEAR 2000 POSES POTENTIAL RISKS

     We continue to review our "Year 2000" readiness. The Year 2000 issue stems
from the predominant use in computer applications of a two-digit field to
capture the year (e.g., "99" for 1999). Because the "19" is assumed in the date,
when computers turn their clocks to the year 2000, the two-digit field will read
"00" and some computer programs will assume the year is 1900. Programs that
calculate, compare or sort on a date field may cause erroneous results and
errors leading to the risk of business interruption or shutdown and other
potential problems. The Year 2000 issue is a global issue that is very complex
because of the many programs that may be impacted in any computer system. These
computer systems are used to support the activities of our businesses including
financial systems, process control technology and other computer-controlled
equipment.

                                       11
<PAGE>   19

     The following is a list of representative types of risks that could result
in the event of one or more major failures of our information systems, mining
sites, or facilities to be Year 2000 ready, or similar major failures by one or
more of our major third party suppliers or customers:

     - Information systems -- could include disruptions of business and
       transaction processing such as customer billing, payroll, accounts
       payable, purchasing, and other information processes until the systems
       can be remedied or replaced;

     - Mining facilities -- could include disruptions of mining processes and
       facilities resulting in delays in delivery of products until
       non-compliant components can be remedied;

     - Major suppliers -- could include disruptions in the provision of supplies
       and components and transportation that could cause subsequent
       interruptions of mining activities and delays in product deliveries; and

     - Major customers -- could include disruptions in sales, revenue, and cash
       inflow as a particular customer may not be Year 2000 compliant or one of
       their suppliers may experience failures that could impact the amount of
       copper, molybdenum, or coal they require.

Failure to correct a material Year 2000 problem could materially and adversely
affect our results of operations, liquidity and financial condition. Due to the
general uncertainty inherent in the Year 2000 issue, resulting in part from the
uncertainty of the readiness of suppliers and customers, we are unable to
determine with any certainty the consequences of Year 2000 failures and the
materiality of these potential failures. In addition, we cannot make any
assurances about the Year 2000 readiness of Asarco or Cyprus Amax.

                                       12
<PAGE>   20

                            THE PROPOSED COMBINATION

     We are proposing a three-way business combination of Phelps Dodge, Asarco
and Cyprus Amax that we believe will create superior value for the shareholders
of all three companies.

     We are offering to exchange all of the outstanding Cyprus Amax common
shares for Phelps Dodge common shares at an exchange ratio of 0.3135 Phelps
Dodge common shares for each Cyprus Amax common share. We are also separately
offering to exchange all of the outstanding Asarco common shares for Phelps
Dodge common shares at an exchange ratio of 0.4098 Phelps Dodge common shares
for each Asarco common share. We expect our proposed transaction to be tax-free
to you.

     In July 1999, Asarco and Cyprus Amax announced that they had agreed to
combine their companies. We believe our proposed three-way business combination
is much more valuable to shareholders of Asarco and Cyprus Amax than the
proposed two-party Asarco-Cyprus Amax merger, based on:

     - the sizeable premium we are offering which, in effect, represents an
       up-front payment to you for the substantial cost savings we expect to
       achieve;

     - our plan to continue Phelps Dodge's current $2.00 per share dividend,
       resulting in a substantial dividend increase for Asarco and Cyprus Amax
       shareholders to 4.1 times the level contemplated in the proposed
       Asarco-Cyprus Amax merger; and

     - your opportunity to participate in the greater upside potential of the
       combined entity through the ownership of Phelps Dodge common stock.

     We have conducted an in-depth analysis of our proposed three-way
combination from a regulatory perspective and have concluded that we will be
able to obtain all necessary approvals on a timely basis.

     We have made numerous requests to the management and Boards of Directors of
Asarco and Cyprus Amax to meet with us to discuss our proposal and why we
believe it is far superior to the proposed no-premium Asarco-Cyprus Amax merger.
However, despite our repeated requests, the management and Boards of Directors
of Asarco and Cyprus Amax have been unwilling to meet with us. For this reason,
we are making these offers directly to the shareholders of Asarco and Cyprus
Amax. See "Background of the Offer" beginning on page 16. We believe that the
ultimate decisions about the future of Cyprus Amax belong to you, the
shareholders.

     We would prefer to combine all three companies. However, our offer to
Cyprus Amax shareholders is not conditioned on the success of our offer to
Asarco shareholders, nor is our offer to Asarco shareholders conditioned on the
success of our offer to Cyprus Amax shareholders. See "The Offer" beginning on
page 32.

                                       13
<PAGE>   21

                      REASONS FOR THE PROPOSED COMBINATION

     We believe the combination of Phelps Dodge, Asarco and Cyprus Amax
represents a unique opportunity to create a large, resource-rich portfolio of
lower-cost global copper assets with enhanced flexibility to excel through
business cycles. We believe that the combination of Phelps Dodge, Asarco and
Cyprus Amax will produce the following valuable benefits:

     - Ability to integrate operations.  We expect the combined company to have
       significantly greater ability to integrate southwest U.S. mining
       operations, administrative functions in the U.S., Chile and Peru, and
       worldwide exploration and development activities. Following the
       combination, we would expect to operate all properties in accordance with
       Phelps Dodge's disciplined management approach. This means that each
       property would be run on a basis intended to earn in excess of the cost
       of capital over the full copper price cycle.

     - Accretion to cash flow.  The combination would result in immediate and
       substantial accretion to the cash flow of the combined company.

     - Accretion to earnings.  We expect the combination to result in
       significant accretion to earnings per share of the combined company in
       the second year, assuming copper prices of $0.80 -- $0.85 per pound.

     - Superior production capability.  The total annual worldwide copper
       production of the combined company would be approximately 3.8 billion
       pounds at current levels, with total attributable copper reserves of
       approximately 80 billion recoverable pounds.

     - Substantial cost savings.  We expect the combined company to achieve
       annual cash cost savings of at least $200 million by the end of the
       second year after closing, as a result of reductions in overhead,
       purchasing, exploration and other expenses. We also expect at least
       another $65 million in annual savings from reduced depreciation expenses,
       bringing the total annual savings to at least $265 million. These cost
       savings are based on public information and our expectation that we can
       deliver at least $75 million in incremental savings above the cash
       synergy figure of $125 million projected in the proposed Asarco-Cyprus
       Amax merger. This does not include any cost savings from the
       rationalization of high-cost production during periods of low copper
       prices.

     - Management strength.  The combined company would have a strong and deep
       management team, at both the operating and corporate levels, with strong
       credibility in the marketplace. Phelps Dodge's management team would have
       the opportunity to implement value-based portfolio management. We believe
       that Phelps Dodge's management team has the credibility to make the tough
       decisions necessary to integrate all three businesses rapidly and to
       build sustainable long-term shareholder value.

     - Portfolio of world-class copper mines.  The combined company would have a
       core portfolio of world-class copper mines, including Morenci, Southern
       Peru Copper Corporation, El Abra, Cerro Verde and Candelaria. This core
       portfolio would represent more than 50% of the combined company's current
       annual production. At current levels, these properties would produce
       approximately 2 billion pounds of copper annually, at an average cash
       cost of less than $0.50 per pound.

     - Operating leverage.  The combined company would have tremendous operating
       leverage, together with enough diversity in other businesses to mitigate
       cyclical downturns.

     - Increased competitiveness.  The combined company would have increased
       ability to compete for world-class projects.

     - Reduced capital expenditures.  By combining their businesses, Phelps
       Dodge, Asarco and Cyprus Amax would be able to reduce maintenance and
       growth capital expenditures significantly.

     - Financial strength.  The combined company would have a strong, liquid
       balance sheet, with excellent access to capital. The company's financial
       strength would give it the ability to create a world-class portfolio of
       cost-competitive mining assets.

                                       14
<PAGE>   22

     We believe these factors will provide superior value creation
opportunities, on an ongoing basis, for the shareholders of all three companies.
We believe that your ability to participate in this value creation, through your
ownership of Phelps Dodge common stock, is an important element of our proposal.
Over the past several years, Phelps Dodge's stock price has significantly
outperformed the stock prices of Asarco and Cyprus Amax. As a result of Phelps
Dodge's higher dividend, the level of outperformance is even greater when viewed
on the basis of the total return to shareholders assuming reinvestment of
dividends:

     - Over the past 15 years, Phelps Dodge's total return has been 1,024% as
       compared to 25% for Asarco and 102% for Cyprus Amax (Cyprus Amax's total
       return is measured from Cyprus Amax's May 1985 initial public offering).

     - Over the past 10 years, Phelps Dodge's total return has been 161% as
       compared to negative 20% for Asarco and negative 26% for Cyprus Amax.

     - Over the past five years, Phelps Dodge's total return has been 20% as
       compared to negative 27% for Asarco and negative 40% for Cyprus Amax.

While we cannot make assurances about future returns, we believe that our
performance record indicates that we are best equipped to extract value out of
the Asarco and Cyprus Amax assets.

                                       15
<PAGE>   23

                            BACKGROUND OF THE OFFER

     In the autumn of 1996, Douglas C. Yearley, Chairman and CEO of Phelps
Dodge, had an informal conversation with Richard de J. Osborne, then Chairman,
Chief Executive Officer and President of Asarco, regarding a possible
combination of the two companies. Mr. Osborne declined to hold discussions on
this subject.

     On July 15, 1999, Asarco and Cyprus Amax announced that they had agreed to
combine their companies into a new company to be called "Asarco Cyprus
Incorporated." According to the press release issued by Asarco and Cyprus Amax,
Cyprus Amax shareholders would receive 0.765 shares of the combined company for
each of their Cyprus Amax shares, while Asarco shareholders would receive one
share of the combined company for each of their Asarco shares. The combined
company would have an initial dividend rate of $0.05 per share per quarter. The
transaction was approved by the Boards of Directors of Asarco and Cyprus Amax,
but remains subject to regulatory approvals and shareholder approvals.

     On August 10, 1999, Douglas C. Yearley, Phelps Dodge's Chairman and Chief
Executive Officer, telephoned Milton H. Ward, Cyprus Amax's Chairman, Chief
Executive Officer and President, and Francis R. McAllister, Asarco's Chairman
and Chief Executive Officer, to propose a meeting to discuss the possibility of
a three-way combination involving Phelps Dodge, Asarco and Cyprus Amax. Shortly
thereafter, Messrs. Ward and McAllister sent the following letter to Mr.
Yearley:

                                                                 August 10, 1999

Douglas C. Yearley
Chairman, President and
  Chief Executive Officer
Phelps Dodge Corporation
2600 North Central Avenue -- 16th Floor
Phoenix, AZ 85004-3014

Dear Doug:

     We have discussed your request to meet with us jointly. We would like to
advise you that Cyprus Amax and Asarco are pursuing a combination under a Merger
Agreement dated July 15, 1999. Under the terms of that Agreement we are not at
liberty to have a discussion of the nature you were suggesting earlier today.

                                         Best regards.

/s/ MILTON H. WARD
- ------------------------------------------
Milton H. Ward
Chairman, Chief Executive Officer
  and President
Cyprus Amax Minerals Company
/s/ FRANCIS R. MCALLISTER
- ------------------------------------------
Francis R. McAllister
Chairman and Chief Executive Officer
ASARCO Incorporated

                                       16
<PAGE>   24

     On August 11, 1999, during the late afternoon, Mr. Yearley and J. Steven
Whisler, Phelps Dodge's President and Chief Operating Officer, sent the
following letter to Messrs. McAllister and Ward:

                    [LETTERHEAD OF PHELPS DODGE CORPORATION]

                                                                 August 11, 1999

Francis R. McAllister
Chairman and Chief Executive Officer
ASARCO Incorporated
180 Maiden Lane
New York, NY 10038

Milton H. Ward
Chairman, Chief Executive Officer and President
Cyprus Amax Minerals Company
9100 East Mineral Circle
Englewood, CO 80112

Dear Frank and Milt:

     We are disappointed that you have declined to meet with us. As you know
from our telephone conversations, we have considered your pending business
combination and would like to discuss with you our proposal, described in more
detail below, to combine all three of our companies in a negotiated transaction.

     We believe that a three-way combination of Phelps Dodge, Asarco and Cyprus
Amax would create superior shareholder value for the shareholders of Asarco and
Cyprus Amax. A three-way combination, by creating a lower-cost global
competitor, would also benefit the employees and customers of all three
companies. For these reasons, we are approaching you to discuss the concept of a
three-way combination.

     We propose that all of the outstanding common stock of both Asarco and
Cyprus Amax be exchanged for Phelps Dodge common stock. The transaction would be
tax-free to your shareholders.

     A combination of these businesses would result in cost savings well in
excess of the amounts you have indicated to be achievable through your pending
merger. Preliminarily we estimate that the annual cash cost savings should reach
at least $150 million.

     We propose to reward your shareholders for these substantial incremental
benefits by offering your shareholders an exchange ratio of 0.3756 Phelps Dodge
common shares for each Asarco common share and 0.2874 Phelps Dodge common shares
for each Cyprus Amax common share. These exchange ratios preserve the relative
economics of your proposed combination and imply premiums of approximately 25%
based on current market prices for Asarco and Cyprus Amax.

     We believe this proposal creates superior value for your shareholders based
on:

     - the sizeable premium we are offering which, in effect, represents an
       up-front payment to your shareholders for the substantial cost savings we
       expect to achieve;

     - their opportunity to participate in the ongoing value creation of the
       combined company; and

     - our planned continuation of the current $2.00 per share Phelps Dodge
       common stock dividend resulting in substantial dividend increases for
       both Asarco and Cyprus Amax shareholders to 3.76 times the level
       contemplated in your pending merger.

     Our preference is for a combination of all three companies, which would of
course involve the consent of both Asarco and Cyprus Amax to a modification of
your existing agreement.

                                       17
<PAGE>   25

     Since your merger agreement has not been publicly filed, we have not had
the opportunity to review its terms. Based on your August 10, 1999 letter, it is
unclear to us whether discussions may proceed once you receive a written
proposal such as this letter. In any event, if necessary under your merger
agreement, we request that you grant one another waivers to allow meetings with
us on our proposal which, as discussed below, would be far more favorable to
your shareholders than your proposed merger.

     We are confident that the market reaction to a three-way combination would
be positive. In particular we believe the market would recognize:

     - the significantly stronger ability of the combined company, relative to
       the Asarco-Cyprus Amax combination, to integrate southwest U.S. mining
       operations, administrative functions in Chile and Peru and world-wide
       exploration and development activities;

     - the financial strength of the combined company and ability to create a
       world class portfolio of cost competitive mining assets;

     - a strong and deep management team, at both the operating and corporate
       levels, with strong credibility in the marketplace;

     - the ability to eliminate substantial overhead, exploration, purchasing
       and other expenses through the consolidation;

     - the tremendous operating leverage of the combined company, together with
       enough diversity in other businesses to mitigate cyclical downturns;

     - the ability of the combined company to reduce capital expenditures;

     - a strong, liquid balance sheet, with excellent access to capital; and

     - how all of these factors would build greater shareholder value, on an
       ongoing basis, for the shareholders of all three companies.

     This is intended to be a confidential proposal which is subject to the
execution of a definitive merger agreement and receipt of customary approvals,
including approval by our respective Boards of Directors and shareholders. We
have conducted in-depth analyses of the proposed three-way combination from a
regulatory perspective and have concluded that it will be possible to obtain the
necessary approvals on a timely basis.

     We believe that our proposal is substantially more attractive to your
shareholders than your pending merger. In addition to the sizeable premium we
are offering, your shareholders would participate, through their ongoing Phelps
Dodge common stock ownership, in a larger enterprise with greater realizable
cost savings and synergies, a stronger portfolio of cost competitive assets and
a deep management team with a strong operating record. We have no doubt that
your shareholders will enthusiastically embrace our proposal once they learn of
it.

     We have discussed this proposal with our Board, which fully supports it. We
are confident of our ability, with your cooperation, to complete this
transaction as quickly as your proposed two-party Asarco-Cyprus Amax merger.

                                       18
<PAGE>   26


     We are firmly committed to moving forward quickly to consummate this
transaction. As we mentioned, we would be happy to meet with you in New York or
another mutually convenient location to amplify our proposal. In any event, we
would appreciate a response by 5:00 p.m., New York time, on Wednesday, August
18, 1999.


                                         Sincerely,

/s/ DOUGLAS C. YEARLEY
- ------------------------------------------
Douglas C. Yearley
Chairman and
  Chief Executive Officer
/s/ J. STEVEN WHISLER
- ------------------------------------------
J. Steven Whisler
President and Chief
  Operating Officer

     On the morning of August 12, 1999, Messrs. McAllister and Ward telephoned
Mr. Yearley and once again refused to meet to discuss Phelps Dodge's proposal.
That afternoon, Phelps Dodge sent the following letter to the Board of Directors
of Cyprus Amax (and sent a substantially similar letter to the Board of
Directors of Asarco):

                    [LETTERHEAD OF PHELPS DODGE CORPORATION]

                                                                 August 12, 1999

Board of Directors of Cyprus Amax Minerals Company
c/o Mr. Milton H. Ward
Chairman, Chief Executive Officer and President
Cyprus Amax Minerals Company
9100 East Mineral Circle
Englewood, CO 80112

Ladies and Gentlemen:

     We would like to engage in discussions on our proposal to combine Cyprus
Amax, Asarco and Phelps Dodge in a negotiated transaction. Our proposal,
described in more detail in the attached correspondence, is far better for the
shareholders of your company than your pending merger with Asarco because of:

     - the sizeable premium we are offering which, in effect, represents an
       up-front payment to your shareholders for the substantial cost savings we
       expect to achieve;

     - our planned continuation of the current $2.00 per share Phelps Dodge
       common stock dividend resulting in a substantial dividend increase for
       Cyprus Amax shareholders to more than three times the level contemplated
       in your pending merger; and

     - their opportunity to participate in the ongoing value creation of the
       combined company through the ownership of Phelps Dodge common stock.

     In our attached letter of August 11, we proposed specific exchange ratios
of Phelps Dodge shares for Asarco and Cyprus Amax shares. Based on the August 11
closing price of Phelps Dodge, Cyprus Amax and Asarco shares, these ratios
implied premiums of approximately 25% for each of Cyprus Amax and Asarco and
preserved the relative economics of your proposed combination with Asarco. We
would reiterate our intention on the basis of the current levels of Phelps
Dodge, Cyprus Amax and Asarco share prices to pay premiums of approximately 25%
for Cyprus Amax and Asarco.

     We believe that consideration in the form of Phelps Dodge common stock
should be particularly attractive to your shareholders. Over the past several
years Phelps Dodge's stock price has significantly

                                       19
<PAGE>   27

outperformed the stock prices of Cyprus Amax and Asarco. As a result of Phelps
Dodge's higher dividend, the level of outperformance is even greater when viewed
on the basis of the total return to shareholders assuming reinvestment of
dividends. Over the past 10 years Phelps Dodge's total return has been 161% as
compared to -26% and -20% for Cyprus Amax and Asarco, respectively. Similarly,
over the past five years, Phelps Dodge's total return has been 20% as compared
to -40% for Cyprus Amax and -27% for Asarco. We are very proud of this strong
management and operational track record over a difficult copper environment.

     Thus far, however, your management has refused to listen to, or consider,
our proposal.

     On Tuesday afternoon, August 10, 1999, following a meeting of our board of
directors, we spoke by telephone with Messrs. Ward and McAllister to request a
meeting to discuss our proposal. Just a few hours later, we received from them
the attached letter, dated August 10, 1999, advising that under the terms of a
non-public July 15, 1999 Merger Agreement they were "not at liberty" to have
such a discussion.

     Since Messrs. Ward and McAllister refused to meet with us, late yesterday
we sent them the enclosed August 11 letter laying out the basic terms of our
proposal and again requesting a meeting.

     This morning we received a telephone call from Messrs. Ward and McAllister
again refusing to discuss our proposal.

     Although it would have been our preference to communicate through your CEO,
his adamant refusal to meet with us, or even to give our written proposal any
serious consideration, has required that we communicate with you directly. Since
you and Asarco are the only parties to your merger agreement, and may amend it
or waive its provisions at any time, for management of the two companies to
state that their own agreement prevents such discussions seems a particularly
weak basis for their refusal even to meet with us.

     We are making a similar proposal to Asarco. Our willingness to enter into
discussions with each of you is not conditioned on the participation of the
other (assuming this is consistent with any applicable, binding contracts).

     We are resolute in our determination to complete this transaction with both
companies. We are confident that your shareholders will recognize the superior
benefits of our proposal, and will accept nothing less.

     We still strongly prefer to consummate this transaction on a mutually
satisfactory, negotiated basis. Accordingly, we do not plan to disclose our
proposal publicly at this time. Because of the importance of this matter to your
shareholders, we request that you make a commitment, by 5:00 p.m. Friday, August
20, 1999, to meet with us promptly to commence serious negotiations.

                                         Sincerely,

/s/ DOUGLAS C. YEARLEY
- ------------------------------------------
Douglas C. Yearley
Chairman and
Chief Executive Officer
/s/ J. STEVEN WHISLER
- ------------------------------------------
J. Steven Whisler
President and Chief
Operating Officer

                                       20
<PAGE>   28

     On August 20, 1999, Asarco and Cyprus Amax filed a joint proxy
statement/prospectus in connection with their proposed merger, and for the first
time disclosed the terms of their merger agreement. In addition, Asarco and
Cyprus Amax issued a press release announcing that they had set August 25, 1999
as the record date for determining shareholders entitled to vote at the
shareholder meetings, scheduled for September 30, 1999, to consider approval of
their proposed merger. Asarco and Cyprus Amax also disclosed Phelps Dodge's
proposal for a three-way business combination and announced that they were
rejecting it. Asarco and Cyprus Amax also revised upward their estimates of
synergies resulting from their proposed two-party merger. The text of the press
release was as follows:

     DENVER, CO. and NEW YORK, N.Y., August 20, 1999 -- Cyprus Amax Minerals
(NYSE:CYM) and ASARCO Incorporated (NYSE:AR) announced that they have set
shareholder meetings for September 30, 1999 to approve their previously
announced merger of equals. Asarco Cyprus Incorporated will be the largest
publicly traded copper company with an estimated cash cost of under 50 cents.
Definitive proxy materials will be mailed to shareholders of record on August
25, 1999.

     Cyprus and Asarco also announced that joint Asarco and Cyprus merger teams
are reviewing all operating and administrative aspects of the new organization
to identify organizational and other profit driven changes in the way they do
business. The companies have engaged outside consultants to assist in
identification of cost savings to facilitate the process. As a result of these
reviews, the estimate of annual expense reductions is now approaching $200
million including $50 million in reduced administrative and overhead costs, $50
million from lower costs of purchased materials and services, $25 million in
other costs and $75 million in lower depreciation. As part of the cost
reductions, Cyprus' Denver office will be closed and Asarco's New York office
will be downsized and relocated to New Jersey. In addition, the companies
believe the merger will provide the flexibility to rationalize higher cost
production during periods of low copper prices, which could be expected to
result in operational cash improvements approaching $75 million annually.

     Cyprus and Asarco also jointly reported that the Boards of both companies
had received an unsolicited proposal from Phelps Dodge Corporation to negotiate
an agreement for Phelps Dodge to acquire both companies for stock. Phelps Dodge
proposed an exchange of .3756 of a Phelps Dodge share for each Asarco share and
 .2874 of a Phelps Dodge share for each Cyprus share. Phelps Dodge's proposal is
subject to a number of contingencies.

     On August 19, 1999, the Asarco Board of Directors and the Cyprus Amax Board
of Directors, together with their respective legal and financial advisors, met
separately to consider the unsolicited proposal from Phelps Dodge. Both the
Asarco Board of Directors and the Cyprus Amax Board of Directors determined that
pursuing the Asarco Cyprus merger was in best interests of Asarco and Cyprus
Amax stockholders, respectively, and reconfirmed their respective
recommendations of the merger.

     Since the merger announcement, both Boards noted that the share prices of
Cyprus and Asarco have outperformed the other U.S. listed copper companies.
Asarco Cyprus expects that at its estimated cash costs of under 50 cents per
pound, it will require a copper price of less than 65 cents per pound to
breakeven on a net earnings basis. Asarco Cyprus will have a strong, experienced
management team and the financial capacity to further enhance operating
efficiencies, expand or develop low cost copper properties and otherwise
rationalize operations to achieve optimum operating levels.

                                       21
<PAGE>   29

     Also on August 20, 1999, Asarco and Cyprus Amax sent the following letter
to Phelps Dodge:

                                         August 20, 1999

Mr. Douglas C. Yearley
Chairman, President and
  Chief Executive Officer
Phelps Dodge Corporation
2600 North Central Avenue
Phoenix, AZ 85004-3050

Dear Doug:

     We have tried to reach you this morning to convey the response of our
respective Boards and to share with you the attached press release.

     Each of our companies has convened its Boards and received thorough
presentations from financial and legal advisors. After full consideration of
your proposal, each Board unanimously decided that it was in the best interests
of its shareholders to pursue the Asarco Cyprus merger. That is what we intend
to do.
                                         Sincerely,

/s/ FRANCIS R. MCALLISTER
- ------------------------------------------
Francis R. McAllister
Chairman and Chief
  Executive Officer
  Asarco Incorporated
/s/ MILTON H. WARD
- ------------------------------------------
Milton H. Ward
Chairman, Chief Executive
  Officer and President
  Cyprus Amax Minerals Company

     During the afternoon of August 20, 1999, Phelps Dodge made the following
announcement by press release:

           PHELPS DODGE PROPOSES TO ACQUIRE ASARCO AND CYPRUS AMAX IN
                 STOCK TRANSACTIONS AT APPROXIMATE 30% PREMIUMS

   UNIQUE OPPORTUNITY TO CREATE PORTFOLIO OF LOWER-COST GLOBAL COPPER ASSETS

     PHOENIX, AZ, August 20, 1999 -- Phelps Dodge Corporation (NYSE: PD)
announced today that it is proposing to acquire both Asarco Incorporated (NYSE:
AR) and Cyprus Amax Minerals Company (NYSE: CYM) in stock-for-stock mergers that
would provide approximate 30% premiums to the shareholders of both companies.
Neither proposal is conditioned upon acceptance of the other.

     On July 15, 1999, Asarco and Cyprus Amax announced a no-premium merger
subject to shareholder approval. Phelps Dodge has since made numerous
unsuccessful attempts to negotiate business combinations with both companies on
terms that are greatly superior for Asarco and Cyprus Amax shareholders.

     Phelps Dodge would acquire Asarco in a tax-free merger in which each share
of Asarco common stock would be converted into 0.4098 Phelps Dodge common
shares. Based on the share prices of Phelps Dodge and Asarco before the stocks
were halted this morning, the proposal values Asarco at $24.05 per share, or a
total equity value of approximately $960 million, representing an approximate
30% premium for Asarco shareholders.

     Phelps Dodge would acquire Cyprus Amax in a tax-free merger in which each
share of Cyprus Amax common stock would be converted into 0.3135 Phelps Dodge
common shares. Based on share prices of Phelps Dodge and Cyprus Amax before the
stocks were halted this morning, the proposal values Cyprus Amax at $18.40 per
share, or a total of equity value of approximately $1.7 billion, representing an
approximate 29% premium for Cyprus Amax shareholders.

                                       22
<PAGE>   30

     The Phelps Dodge proposals represent a unique opportunity to create a
large, resource-rich portfolio of lower-cost global copper assets with enhanced
flexibility to excel through business cycles. This three-way combination would
also provide significantly greater opportunities to integrate operations in the
southwestern United States, administrative functions in the United States, Chile
and Peru, and worldwide exploration and development activities than the proposed
Asarco/Cyprus Amax merger. Consistent with demonstrated Phelps Dodge standards,
all Asarco and Cyprus Amax properties would be operated to earn more than the
cost of capital over the copper cycle. At current levels, annual worldwide
copper production of the combined companies would be approximately 3.8 billion
pounds, with attributable copper reserves of approximately 80 billion pounds,
predominantly in the U.S., Chile and Peru.

     Phelps Dodge expects the three-way combination to be immediately and
substantially accretive to its cash flow, with significant opportunities to
improve return on capital at the combined entity. The transactions would be
significantly accretive to Phelps Dodge's earnings per share beginning in the
second year after closing, based on the current portfolio of the combined
companies and analysts' estimates of copper prices of $0.80 to $0.85 per pound
in 2001.

     Phelps Dodge expects to achieve annual cash cost savings of at least $200
million, to be fully phased in by the end of the second year after closing,
through reductions in SG&A expenses, operating improvements and efficiencies in
exploration. Additional non-cash savings of approximately $65 million per year
are expected to result from lower depreciation charges. These cost savings are
based on public information and the Company's expectation that it can deliver at
least $75 million in incremental savings above the new cash synergy figure of
$125 million now projected in the proposed Asarco/Cyprus Amax combination. This
does not include any cost savings for the rationalization of high-cost
production during periods of low copper prices. The transactions would use
purchase accounting.

     Phelps Dodge intends to continue its current annual cash dividend of $2.00
per share. This would provide a substantial dividend increase to shareholders of
both Asarco and Cyprus Amax -- equal to 4.1 times the dividend they would
receive in the proposed Asarco/Cyprus Amax merger.

     Douglas C. Yearley, Chairman and Chief Executive Officer of Phelps Dodge,
said, "We are very disappointed that Asarco and Cyprus Amax have declined our
repeated attempts to enter into negotiated agreements. Our proposed three-way
combination provides superior value to shareholders of Asarco and Cyprus Amax,
including substantial premiums, the opportunity to participate in the tremendous
upside potential of the combined entity, and a cash dividend that is more than
quadruple what they would receive in the proposed Asarco/Cyprus Amax
transaction."

     Yearley continued, "This compelling combination would create a more
cost-effective global copper producer with the operating expertise, broad
resource base and financial strength to deliver enhanced value to shareholders
of all three companies. The improved efficiencies of the combined companies
would also benefit other stakeholders, including our customers, employees and
communities. In the global copper market, efficient and low-cost operations are
critical, and this transaction would enhance our ability to compete and give us
greater ability to satisfy our customers' needs. Customers would continue to
enjoy Phelps Dodge's high standard of on-time delivery and quality products and
benefit from our combined lower cost structure; employees would become part of a
stronger organization with enhanced ability to compete for large-scale projects;
and communities would benefit from our corporate citizenship and philanthropy
and continued commitment to responsible environmental practices."

     J. Steven Whisler, President and Chief Operating Officer of Phelps Dodge,
said, "We are committed to optimizing the combined operations of the three
companies and delivering superior returns on capital throughout the entire
copper cycle. Phelps Dodge has generated much better shareholder returns than
Asarco and Cyprus Amax through copper cycles -- greatly outperforming both
companies over the past three, five, 10 and 15-year periods. For example, during
the past 10 years on a total return basis with dividends reinvested Phelps Dodge
has produced a positive shareholder return of 161% versus negative 20% for
Asarco and negative 26% for Cyprus Amax. Over the 15-year period, Phelps Dodge
has produced a positive shareholder return of 1024% versus 25% for Asarco and
102% for Cyprus Amax.
                                       23
<PAGE>   31

Phelps Dodge's strong and deep management and operating teams have a proven
track record of active, value-based portfolio management and of taking decisive
actions required to build sustainable long-term shareholder value. We intend to
take advantage of the substantial opportunities to integrate the combined
companies' mining assets and will ensure that every property in the portfolio
provides an appropriate return on invested capital."

     Yearley concluded, "This innovative three-way combination fits well with
our strategy of sustaining a strong and liquid balance sheet, achieving earnings
and cash flow accretion and improving our resource base, while maintaining a
cost-competitive profile. While we continue to prefer negotiated transactions,
this three-way combination is so compelling, both strategically and financially,
that we are determined to take all necessary steps to complete it expeditiously.
We are confident we will obtain the necessary regulatory approvals to complete
the transactions and believe shareholders of Asarco and Cyprus Amax will
strongly support this unique opportunity to create value in the global copper
market in which we compete."

     Phelps Dodge's financial advisor is Morgan Stanley Dean Witter and its
legal advisors are Debevoise & Plimpton and Shearman & Sterling.

     Phelps Dodge Corporation is among the world's largest producers of copper.
The company also is one of the world's largest producers of carbon black, one of
the world's largest manufacturers of magnet wire, and has operations and
investments in mines and wire and cable manufacturing facilities around the
world. Phelps Dodge has operations in 28 countries.


     Statements in this press release include "forward-looking statements" that
express expectations of future events or results. All statements based on future
expectations rather than on historical facts are forward-looking statements that
involve a number of risks and uncertainties, and the company cannot give
assurance that such statements will prove to be correct. Please refer to the
Management's Discussion and Analysis sections of the company's report on Form
10-K for the year ended December 31, 1998.




     Later that day, Phelps Dodge sent the following letter to the Board of
Directors of Cyprus Amax (and sent a substantially similar letter to the Board
of Directors of Asarco):

                    [LETTERHEAD OF PHELPS DODGE CORPORATION]

                                                                 August 20, 1999

Board of Directors of Cyprus Amax Minerals Company
c/o Mr. Milton H. Ward
Chairman, Chief Executive Officer and President
Cyprus Amax Minerals Company
9100 East Mineral Circle
Englewood, CO 80112

Ladies and Gentlemen:

     We are disappointed in your response to our proposed three-way combination
of Cyprus Amax, Asarco and Phelps Dodge. As you know, we have on three recent
occasions requested the opportunity to discuss our proposal, which we believe
would be far superior to your shareholders than your proposed combination with
Asarco.

     We are particularly disappointed that instead of accepting our previous
requests to meet to discuss our proposal to acquire Cyprus Amax for a
substantial premium, you chose today to announce unilaterally our interest in
acquiring Cyprus Amax and Asarco and to reject our proposal in favor of your
no-premium merger proposal with Asarco. This appears consistent with the manner
in which you have chosen to treat your own shareholders by announcing just
today, at the same time you first disclosed the

                                       24
<PAGE>   32

terms of your July 15 merger agreement, that the record date for your
shareholder vote on the no-premium merger with Asarco would be August 25. Since
trades after today will settle after August 25, this effectively precluded any
significant trading in the market on an informed basis before the determination
of shareholders eligible to vote at your meeting.

     In light of your unilateral announcement, we have no other choice than to
publicly announce our proposal to enter into a business combination with Cyprus
Amax and Asarco, so that share owners of all three companies are fully informed.

Terms of our Proposal

     We propose a business combination of Phelps Dodge and Cyprus Amax pursuant
to which all of the outstanding common stock of Cyprus Amax would be exchanged
for Phelps Dodge common stock at an exchange ratio of 0.3135 Phelps Dodge common
shares for each Cyprus Amax common share. We are also independently proposing to
Asarco a business combination of Phelps Dodge and Asarco pursuant to which all
of the outstanding common stock of Asarco would be exchanged for Phelps Dodge
common stock at an exchange ratio of 0.4098 Phelps Dodge common shares for each
Asarco common share. Based on share prices for the three companies' common
shares before trading was halted this morning, these ratios imply a premium of
approximately 29% for Cyprus Amax and a premium of approximately 30% for Asarco,
while preserving the relative economics of the exchange ratio under your
proposed combination with Asarco.

     Following the combination, we plan to continue the current $2.00 per share
Phelps Dodge common dividend. This would result in a substantial dividend
increase for Cyprus Amax shareholders to 4.1 times the dividend contemplated in
your proposed merger with Asarco.

     Our proposed transaction would be tax-free for your shareholders. In
addition, through their ownership of Phelps Dodge common stock, your
shareholders would continue to participate in the ongoing value creation of the
combined company. Although we prefer a transaction involving all three
companies, we are prepared to enter into a negotiated business combination with
either Cyprus Amax or Asarco, regardless of whether the other company is willing
to proceed on a negotiated basis.

     We believe that consideration in the form of Phelps Dodge common stock
should be particularly attractive to your shareholders. Over the past several
years Phelps Dodge's stock price has significantly outperformed the stock prices
of Cyprus Amax and Asarco. As a result of Phelps Dodge's higher dividend, the
level of outperformance is even greater when viewed on the basis of the total
return to shareholders assuming reinvestment of dividends. Over the past 10
years Phelps Dodge's total return has been 161% as compared to negative 26% and
negative 20% for Cyprus Amax and Asarco, respectively. Similarly, over the past
15 years, Phelps Dodge's total return has been 1024% as compared to 102% for
Cyprus Amax and 25% for Asarco. We are very proud of this strong management and
operational track record over a difficult copper environment.

The Combined Company

     We believe that our proposal presents a unique opportunity to create a
large, resource-rich portfolio of lower-cost global copper assets with enhanced
flexibility to deliver superior results in all business cycles. Our proposal
would create a much stronger company than would your proposed merger with Asarco
through:

     -  the significantly stronger ability of the combined company, relative to
        the Cyprus Amax-Asarco combination, to integrate southwestern U.S.
        mining operations, administrative functions in the U.S., Chile and Peru,
        and worldwide exploration and development activities;

     -  the financial strength of the combined company and ability to create a
        world class portfolio of cost-competitive mining assets;

     -  a strong and deep management team, at both the operating and corporate
        levels, with strong credibility in the marketplace;

     -  the ability to eliminate substantial overhead, exploration, purchasing
        and other expenses through the consolidation;
                                       25
<PAGE>   33

     -  the tremendous operating leverage of the combined company, together with
        enough diversity in other businesses to mitigate cyclical downturns;

     -  the immediate and substantial accretion to the cash flow of the combined
        company resulting from the transaction;

     -  the significant accretion to earnings per share of the combined company
        beginning in the second year after closing, based on the current
        portfolio of the combined companies and analysts' estimates of copper
        prices of $0.80 to $0.85 per pound in 2001;

     -  the total current annual copper production of the combined company of
        3.8 billion pounds and the total attributable copper reserves of 80
        billion pounds;

     -  the increased ability of the combined company to compete for world-class
        projects;

     -  the ability of the combined company to reduce capital expenditures;

     -  the strong, liquid balance sheet of the combined company, with excellent
        access to capital; and

     -  the way all of these factors would build greater shareholder value, on
        an ongoing basis, for the shareholders of all three companies.

     Through the measures described above we estimate that in a three-way
combination we could achieve approximately $200 million in annual cash cost
savings, fully phased in by the end of the second year after closing of the
transaction. In addition, we expect lower depreciation of approximately $65
million annually, bringing total estimated annual savings to approximately $265
million. These cost savings are based on public information and our expectation
that we can deliver at least $75 million in incremental savings above the new
cash synergy figure of $125 million that you have projected in the proposed
Cyprus Amax-Asarco combination. This does not include any cost savings from the
rationalization of high-cost production during periods of low copper prices.

     Following the combination, we would expect to operate all properties in
accordance with Phelps Dodge's disciplined management approach. This means that
each property would be run on a basis intended to earn in excess of the cost of
capital over a full copper price cycle. We believe that Phelps Dodge's
management team has the credibility to make the tough decisions necessary to
rapidly integrate all three businesses and to create value for shareholders.

     A three-way combination, by creating a more efficient global competitor,
would also benefit the employees and customers of all three companies. We have
conducted an in-depth analysis of the three-way combination from a regulatory
perspective and have concluded that it will be possible to obtain the necessary
approvals on a timely basis.

     Our Board of Directors has authorized this proposal and we are resolutely
committed to its consummation. We are confident that your shareholders will find
our proposal to be a unique and compelling opportunity. We continue to prefer to
proceed on a mutually satisfactory, negotiated basis but are prepared to pursue
all other avenues should that be necessary. We are ready to meet with you or
your management at any time.

                                         Sincerely,

/s/ DOUGLAS C. YEARLEY
- ------------------------------------------
Douglas C. Yearley
Chairman and Chief Executive Officer
/s/ J. STEVEN WHISLER
- ------------------------------------------
J. Steven Whisler
President and Chief
Operating Officer

                                       26
<PAGE>   34

     On August 25, 1999, Asarco and Cyprus Amax sent the following letter to
Phelps Dodge:

                                                                 August 25, 1999

Mr. Douglas C. Yearley
Chairman, President and
Chief Executive Officer
Phelps Dodge Corporation
2600 North Central Avenue
Phoenix, AZ 85004-3050

Dear Doug:

     We and our respective boards have considered your revised proposal to
acquire our companies. We have the following issues with your proposal:

     1. The exchange ratios proposed in your August 20 press release do not
        allocate to Cyprus Amax and Asarco holders a fair share of the value
        created by uniting their two companies. We are prepared to negotiate a
        transaction with Phelps Dodge that would provide our holders with .4055
        shares of Phelps Dodge common stock for each Cyprus Amax share, and
        .5300 Phelps Dodge shares for each Asarco share.

     2. In order for us to proceed with Phelps Dodge, you must make clear that
        Phelps Dodge will undertake all actions necessary to secure regulatory
        approval for your proposed transaction including any divestiture or
        similar action required, and will provide credible assurances that such
        regulatory approval will be forthcoming. The statements in your letters
        concerning antitrust issues are not sufficient on this point.

     3. You have not proposed a form of contract for your transaction. We would
        be prepared to proceed on the basis of representations, warranties and
        covenants made by Cyprus Amax and Asarco to each other in their merger
        agreement, with similar representations, warranties and covenants made
        by Phelps Dodge.

     4. Your letter did not indicate whether your proposal was subject to due
        diligence. A due diligence requirement introduces substantial
        uncertainty as to your proposal. We would expect, as part of our effort
        to close our pending merger or any potential transaction with you as
        quickly as possible, that you would not require any further due
        diligence with respect to either Cyrus Amax or Asarco.

     We strongly believe that the combination of Cyprus Amax and Asarco, without
the effect of combining further with Phelps Dodge, provides greater value to
Cyprus Amax and Asarco holders than your August 20 proposal, poses fewer
regulatory issues and can be completed more quickly. Accordingly, we will be
proceeding to present that transaction to our stockholders and to closing on
September 30, 1999. We are prepared, however, to negotiate a transaction that
involves all three companies that satisfies all the foregoing requirements. For
your information, we are attaching to this letter a copy of the press release
Asarco and Cyprus Amax issued today concerning our response to Phelps Dodge. We
also want to advise you that apart from this communication, neither party has
waived any of its legal or other rights, or rights or obligations under our
merger agreement.

                                         Sincerely,

<TABLE>
<S>                                             <C>
/s/ FRANCIS R. MCALLISTER                       /s/ MILTON H. WARD
- -----------------------------------------       ---------------------------------------------------
Francis R. McAllister                           Milton H. Ward
Chairman and Chief                              Chairman, Chief Executive
Executive Officer                               Officer and President
ASARCO Incorporated                             Cyprus Amax Minerals Company
</TABLE>

                                       27
<PAGE>   35

     The text of the attached press release was as follows:

     DENVER, CO AND NEW YORK, NY, AUGUST 25, 1999 -- Cyprus Amax Minerals
Company (NYSE: CYM) and ASARCO Incorporated (NYSE: AR) today jointly announced
that they have improved the terms of their own combination transaction. In
addition they have written to Phelps Dodge outlining their willingness to
negotiate with Phelps Dodge on terms included in the letter. According to the
letter, Asarco and Cyprus Amax would be willing to proceed with a three-way
combination with Phelps Dodge if its proposed exchange ratios are increased, if
Phelps Dodge fully underwrites the risk of antitrust problems with its proposal
and if the contract terms mirror those of the Asarco/Cyprus contract. Asarco and
Cyprus Amax said the exchange ratios they would require were .5300 of a Phelps
Dodge share for Asarco holders and .4055 of a Phelps Dodge share for Cyprus Amax
holders. The letter to Phelps Dodge is attached.

     The two companies also said they have decided to improve the financial
terms of their own combination by including a special payment of $5.00 per share
to the stockholders of the combined Asarco Cyprus Incorporated. The special
payment would be paid to stockholders as soon as possible after consummation of
the merger. Asarco and Cyprus Amax emphasized that they were proceeding with
their two-way combination which, subject to stockholder approval, will close on
September 30, 1999.

     Speaking together, Milton H. Ward, Chairman and Chief Executive Officer of
Cyprus Amax and Francis R. McAllister, Chairman and Chief Executive Officer of
Asarco said "Our response to Phelps Dodge evidences our intent to secure the
best value for our shareholders whether through a three way combination
including Phelps Dodge or through consummation of the merger previously
announced. We have presented very simple terms to Phelps Dodge which we believe
recognize the contributions our two companies make to a three way combination.
The proposal previously communicated by Phelps Dodge fails to reward our
stockholders for the values derived from the Asarco Cyprus transaction. Our
proposed exchange ratio gives recognition to the fact that our shareholders
would be contributing approximately 50% of the value of a three way combination.

     "We intend to move forward to complete our own merger transaction as soon
as possible and as a sign of confidence of our ability to achieve cost
reductions of at least $200 million annually, Asarco Cyprus will make a special
payment to shareholders when the merger closes. This special $5.00 per share
payment reflects the Boards' and managements' confidence in their ability to
deliver benefits from the merger. Asarco Cyprus is expected to have in excess of
$1 billion in cash at the time of closing and the Boards of both companies have
agreed that Asarco Cyprus will pursue the sale of Cyprus Amax's investments in
Kinross Gold and its Australian coal holdings and Asarco's specialty chemicals
business. We would expect the sales to be completed within six months after
closing. Proceeds are expected to approach $1 billion and cash taxes would be
minimized due to tax benefits from the sale of the Kinross shares. Proceeds
would be used to pay down debt and improve the liquidity of the company."

     Messrs. Ward and McAllister stated that they and their respective Boards
are committed to maximizing shareholder value and will continue to do so after
the merger is completed. In order to ensure that Phelps Dodge or any interested
buyer is able to present a bona fide proposal to acquire 100% of the stock of
the Company, during the first 90 days following completion of the merger,
stockholders will have the right to call a meeting to redeem the rights plan. In
addition, change in control provisions in any employment contracts entered into
by the Company will be waived for that same 90 day period.

     In response, Phelps Dodge issued the following press release:

      PHELPS DODGE CONFIRMS RECEIPT OF LETTER FROM ASARCO AND CYPRUS AMAX

     PHOENIX, Aug. 25 -- Phelps Dodge Corporation (NYSE: PD) confirmed that it
has received a letter from Asarco Incorporated (NYSE: AR) and Cyprus Amax
Minerals Company (NYSE: CYM) and issued the following response:

                                       28
<PAGE>   36

     "The proposal put forth by Asarco and Cyprus Amax does not change Phelps
Dodge's commitment to complete a three-way combination that is beneficial to
shareholders of all three companies. While Phelps Dodge will review the most
recent proposal from Asarco and Cyprus Amax, we believe that the Phelps Dodge
proposal, which already provides Asarco and Cyprus Amax shareholders a 30%
premium, a $2.00 annual dividend and very substantial participation in the
greater upside potential of the three-way combination, is fully priced based on
public information and Phelps Dodge's best estimates of the real, achievable
cost synergies in a three-way combination. Phelps Dodge indicated that the
economic aspects of Asarco and Cyprus Amax's proposed three-way merger terms are
totally unreasonable and would deliver nearly all of the economic value of the
three-way combination to Asarco and Cyprus shareholders."

     Douglas C. Yearley, Chairman and Chief Executive Officer of Phelps Dodge,
added, "If Asarco and Cyprus Amax are truly interested in a negotiated
transaction and not just posturing, we would be more than willing to begin real
discussions. Neither company has attempted to sit down with us."

     Phelps Dodge indicated that it intends to complete its review in the near
term and to make a more definitive and comprehensive response thereafter.



     On August 27, 1999, Phelps Dodge issued the following press release:

                 PHELPS DODGE FILES REGISTRATION STATEMENTS FOR
                   EXCHANGE OFFERS FOR ASARCO AND CYPRUS AMAX
                      ------------------------------------

    FILES PRELIMINARY PROXY STATEMENTS TO OPPOSE ASARCO/CYPRUS AMAX MERGER;
                  COMMENCES LITIGATION AGAINST BOTH COMPANIES
 PHELPS DODGE WILL WITHDRAW OFFER AND NOT BID FURTHER IF ASARCO AND CYPRUS AMAX
            SHAREHOLDERS APPROVE TWO-WAY MERGER AT SEPTEMBER 30 VOTE

     PHOENIX, AZ, AUGUST 27, 1999 -- Phelps Dodge Corporation (NYSE: PD)
announced today that it has filed registration materials with the Securities and
Exchange Commission for exchange offers for all outstanding Asarco Incorporated
(NYSE: AR) and Cyprus Amax Minerals Company (NYSE: CYM) common shares. Phelps
Dodge will commence the exchange offers as soon as the registration statements
are declared effective.

     In addition, the Company filed preliminary proxy materials with the
Securities and Exchange Commission to solicit proxies from Asarco and Cyprus
Amax stockholders to vote against the proposed merger of Asarco and Cyprus Amax.
Asarco and Cyprus Amax have set shareholder meetings for September 30, 1999 to
vote on their proposed merger.

     Separately, Phelps Dodge announced that it has commenced litigation in New
Jersey and Delaware against Asarco and Cyprus Amax, respectively, and their
directors, for breaching their fiduciary duties by impermissibly prohibiting
directors from informing themselves of any third-party merger or acquisition
proposal and providing excessive break-up fees.

     "While we continue to prefer negotiated transactions, we are committed to
this compelling three-way combination, and are taking all necessary steps to
complete it," said Douglas C. Yearley, Chairman and Chief Executive Officer of
Phelps Dodge. "If Asarco and Cyprus Amax are truly interested in a negotiated
transaction we are ready to begin discussions immediately. We continue to
believe our offer is fully priced and compelling. We are confident that
shareholders of Asarco and Cyprus Amax will recognize that our proposals are
clearly superior to the Asarco/Cyprus Amax no-premium two-way merger. We view
the September 30 vote as a referendum. If Asarco and Cyprus Amax shareholders do
approve their two-way combination, we will withdraw our substantial premium
proposal and will not bid further."

                                       29
<PAGE>   37

     Phelps Dodge also today sent the following letter to the Chairmen of Asarco
and Cyprus Amax:

                                                                 August 27, 1999

Francis R. McAllister
Chairman and Chief Executive Officer
ASARCO Incorporated
180 Maiden Lane
New York, NY 10038
Milton H. Ward
Chairman, Chief Executive and President
Cyprus Amax Minerals Company
9100 East Mineral Circle
Englewood, CO 80112

Dear Frank and Milt:

     We continue to believe that our proposed three-way combination is clearly
superior for your shareholders than your proposed no-premium, two-party
transaction. Our fully priced proposal provides a substantial premium, our $2.00
annual dividend and opportunity for participation in greater upside potential.

     In your August 25 letter to us you identified four issues with our
proposal. We are prepared to accept three of your points. On the fourth point,
your demand on exchange ratios, we hope that you will reconsider your
unreasonable position and sit down at the table with us to complete our proposed
three-way combination.

     Should you proceed to complete your two-way merger, you will proceed alone
because we will withdraw our substantial premium proposal and will not bid
further. Your September 30 vote will be a referendum on our proposal.

     Your proposal on exchange ratios is so unreasonable that its sincerity is
questionable. It seems to be premised on the flawed assumption that since your
combined production would be comparable to Phelps Dodge's, you should be valued
at the same level as Phelps Dodge. Of course, this is clearly not what investors
believe since it is not reflected in the relative market valuations of the three
companies. The simplistic assumption you seem to be making fails to reflect
Phelps Dodge's long track record of making tough management decisions and
delivering significantly greater value to shareholders than either ASARCO or
Cyprus Amax. Over a fifteen year period we have delivered total returns to
shareholders of 1,024% in contrast to 25% for ASARCO and 102% for Cyprus Amax.

     Moreover, based on the information in your August 20 Form S-4 registration
statement, it appears that the conclusions arrived at by your own investment
bankers do not support your exchange ratio demand. The exchange ratios you have
demanded would deliver nearly all of the incremental value to be derived from a
three-way combination to your shareholders and very little to our shareholders.
This is, as you no doubt anticipated, completely unacceptable to us.

     In addition, we don't believe that your shareholders will be fooled by the
flawed measures you announced which purport to accommodate the possibility of a
third party transaction during the 90 days following completion of your merger.
None of your public statements address in any meaningful way all of the many
steps that would be necessary to give your shareholders a realistic opportunity
to benefit from an attractive third party proposal. Among the additional matters
that would have to be addressed if you were serious about accommodating third
party transactions would be to eliminate your staggered Board and the highly
unusual management entrenchment arrangements built into your two-party merger
agreement.

     Those unusual management-entrenchment provisions guarantee no change in the
roles of the proposed four senior executives of the ASARCO-Cyprus combined
company prior to the 2002 annual
                                       30
<PAGE>   38

meeting except upon a vote of 75% of the Board. Since management will hold 25%
of the Board seats, this effectively requires a unanimous vote of the
non-management directors. Because your Board is divided into three classes, this
means that a buyer of 100% of the outstanding stock of the ASARCO-Cyprus
combined company would not be able to obtain management control for nearly three
years.

     Indeed, even in the two aspects of your 90-day proposal for which you try
to take credit, there is confusion, contradiction and unnecessary complexity.
You propose an unspecified shareholder mechanism to redeem your poison pill
which is inevitably more cumbersome than simple Board action. Secondly, we noted
with interest the statement in your August 25 press release that "In addition,
change in control provisions in any employment contracts entered into by the
Company will be waived for that same 90 day period." We were therefore surprised
to read the contradictory statement in the Form 8-K you filed yesterday that:

       "The rights and benefits under the existing [change of control]
       arrangements with the employees... of each of Cyprus Amax and
       ASARCO, however, will remain in full force and effect and will be
       unaffected during the 90 days following completion of the business
       combination, as will any rights under arrangements entered into
       with such employees in substitution for any existing
       arrangements."

     Frankly, we believe that all of your statements concerning the 90 day
period are no more than a public relations gambit. There is no evidence in your
conduct to date that you have any willingness to pursue transactions that are in
the best interests of your shareholders.

     With regard to the three points in your August 25 letter other than the
exchange ratio, we are pleased to confirm that:

     - We are prepared to enter into a merger agreement with substantially the
       same representations, warranties and covenants as those contained in your
       July 15 merger agreement.

     - This proposal is not subject to due diligence.

     - We have studied the regulatory issues carefully and are confident that
       all necessary regulatory approvals for our three way combination will be
       obtained on a timely basis. We would be pleased to give you strong
       contractual assurances on this point.

     If you take seriously your fiduciary duty and want to inform yourselves
about a compelling transaction that would be in the best interests of your
shareholders, let's sit down and negotiate. If not, your shareholders will
decide which alternative they prefer on September 30.

                                                    Sincerely,

<TABLE>
      <S>                                            <C>

      /s/ DOUGLAS C. YEARLEY                         /s/ J. STEVEN WHISLER
      ------------------------------------------     ------------------------------------------
            Douglas C. Yearley                       J. Steven Whisler
            Chairman and                             President and
            Chief Executive Officer                  Chief Operating Officer
</TABLE>

                                       31
<PAGE>   39

                                   THE OFFER

     We are offering, upon the terms and subject to the conditions set forth in
this prospectus and in the related letter of transmittal, to exchange 0.3135
shares of Phelps Dodge common stock for each outstanding share of common stock
of Cyprus Amax Minerals Company that is validly tendered on or prior to the
expiration date and not properly withdrawn. We are making our offer through our
wholly owned subsidiary, CAV Corporation, which is a Delaware corporation. The
term "expiration date" means 12:00 midnight, New York City time, on October 1,
1999, unless we extend the period of time for which this offer is open, in which
case the term "expiration date" means the latest time and date on which the
offer, as so extended, expires. We are also making a separate offer to exchange
0.4098 shares of Phelps Dodge common stock for each outstanding share of common
stock of ASARCO Incorporated.

     If you tender your shares, you will not be obligated to pay any charges or
expenses of the exchange agent or any brokerage commissions. Except as set forth
in the instructions to the letter of transmittal, transfer taxes on the exchange
of Cyprus Amax common stock pursuant to our offer will be paid by us or on our
behalf.

     We are making this offer in order to acquire control of, and ultimately the
entire common equity interest in, Cyprus Amax. We intend, as soon as possible
after consummation of the offer, to seek to have Cyprus Amax consummate the
Phelps Dodge/Cyprus Amax merger with us in which each outstanding share of
Cyprus Amax common stock (except for Cyprus Amax common stock held by Cyprus
Amax, us or any of our subsidiaries) would be converted into the right to
receive 0.3135 shares of Phelps Dodge common stock.

     If we obtain all of the shares of Cyprus Amax pursuant to our offer to you,
and all of the shares of Asarco pursuant to our separate offer to its
shareholders, former shareholders in Cyprus Amax and Asarco would own
approximately 28% and 16%, respectively, of the shares of common stock of Phelps
Dodge Corporation, based upon the number of shares outstanding of Phelps Dodge,
Cyprus Amax and Asarco on August 13, 1999, August 3, 1999 and July 31, 1999,
respectively.

     Our obligation to exchange shares of Phelps Dodge common stock for Cyprus
Amax shares pursuant to the offer is conditioned upon several conditions
referred to below under "Conditions of Our Offer," including the Minimum Tender
Condition, the Rights Plan Condition, the DGCL 203 Condition, the Fair Price
Condition, the Phelps Dodge Stockholder Approval Condition, the HSR Condition
and other conditions that are discussed below.

     Our offer to acquire Cyprus Amax common stock is also an offer to acquire
Cyprus Amex preferred share purchase rights ("Cyprus Amax Rights"), and, when we
refer to the shares of Cyprus Amax common stock, we are also referring to the
associated rights, unless we indicate otherwise. In addition, all references to
the rights include the benefits to holders of those rights pursuant to the
Cyprus Amax rights agreement (the "Cyprus Amax Rights Agreement"), including the
right to receive any payment due upon redemption of those rights.

     You must tender one Cyprus Amax Right for each Cyprus Amax share tendered
in order to effect a valid tender of Cyprus Amax shares, unless the Cyprus Amax
Rights have been redeemed. The Cyprus Amax Rights are currently represented by
the certificates for the Cyprus Amax shares and your tender of Cyprus Amax
shares prior to the Cyprus Amax Distribution Date will also constitute a tender
of the associated Cyprus Amax Rights. We will not make a separate payment to you
for the Cyprus Amax Rights. Upon the earlier to occur of (a) the close of
business 10 days following a public announcement that a person or group of
associated or affiliated persons other than Cyprus Amax (a "Cyprus Amax
Acquiring Person"), has acquired beneficial ownership of 15% or more of the
outstanding Asarco shares or (b) the close of business 10 business days, or a
later date determined by the Cyprus Amax board of directors, prior to the time
that any person becomes a Cyprus Amax Acquiring Person) following the
commencement of, or a public announcement of an intention to commence, a tender
offer or exchange offer, upon consummation of which such person or group would
be the beneficial owner of 15% or more of such outstanding Cyprus Amax shares
(we refer to the earliest of these dates as the "Cyprus Amax Distribution
Date"), separate certificates representing the Cyprus Amax Rights will be mailed
to holders of record of Cyprus Amax shares as soon as practicable after the
Cyprus Amax Distribution Date, and those separate Cyprus Amax Rights
certificates alone will evidence the Cyprus Amax Rights. The Cyprus Amax
Distribution Date will occur on September 13, 1999, which is the

                                       32
<PAGE>   40

tenth business day following our public announcement of our intent to commence
our offer, unless, before that time, Cyprus Amax 's board of directors decides
to set a later date as the Cyprus Amax Distribution Date.

     If the Cyprus Amax Distribution Date occurs and Cyprus Amax or the related
rights agent distributes separate certificates representing the Cyprus Amax
Rights to you prior to the time that you tender your Cyprus Amax shares pursuant
to our offer, certificates representing a number of Cyprus Amax Rights equal to
the number of Cyprus Amax shares tendered must be delivered to the exchange
agent, or, if available, a book-entry confirmation received by the exchange
agent with respect thereto, in order for those Cyprus Amax shares to be validly
tendered. If the Cyprus Amax Distribution Date occurs and separate certificates
representing the Cyprus Amax Rights are not distributed prior to the time Cyprus
Amax shares are tendered pursuant to our offer, Cyprus Amax Rights may be
tendered prior to the time that you receive the certificates for Cyprus Amax
Rights by use of the guaranteed delivery procedure described under "Procedure
for Tendering" below.

     We have asked Cyprus Amax for its stockholder list and security position
listings to communicate with you and to distribute our offer to you. We may send
this prospectus, related letter of transmittal and other relevant materials to
you and to brokers, dealers, commercial banks, trust companies and similar
persons whose names, or the names of whose nominees, appear on Cyprus Amax's
stockholder list or, if applicable, who are listed as participants in a clearing
agency's security position listing so that we can later send these materials to
beneficial owners of Cyprus Amax shares after we receive these lists from Cyprus
Amax.

TIMING OF OUR OFFER

     Our offer is scheduled to expire at 12:00 midnight, New York City time on
October 1, 1999. For more information, you should read the discussion under the
caption "Extension, Termination and Amendment."

     We intend to call a special meeting of our stockholders to be held as soon
as reasonably practicable after the effective date of the Registration Statement
so that we can obtain the approvals necessary to satisfy the Phelps Dodge
Stockholder Approval Condition.

LITIGATION

     On August 23, 1999, Phelps Dodge, through its directly owned subsidiary CAV
Corporation, sent a written demand to Cyprus Amax for records of its
shareholders, pursuant to Section 220 of the Delaware General Corporation Law.
On August 24, 1999, Phelps Dodge and its directly owned subsidiary AAV
Corporation commenced an action by order to show cause in the Superior Court of
the State of New Jersey, Chancery Division, Mercer County, pursuant to N.J.S.A.
14A:5-28 to seek shareholder records from Asarco. This action is captioned
Phelps Dodge Corp. and AAV Corp. v. ASARCO Inc., Docket No. MER-C-81-99. In
connection with this action, Phelps Dodge made an application for summary
injunctive relief. Asarco opposed the application and argument was heard before
Judge Judith Yaskin on August 26, 1999. At the hearing, the court ruled that
shareholder lists and related documents must be made available to Phelps Dodge
and AAV within forty-eight hours after the filing of their preliminary proxy
materials with the SEC. Some of these materials were delivered to Phelps Dodge
on August 29, 1999.

     In addition, Phelps Dodge has commenced actions in the Superior Court of
the State of New Jersey and in the Court of Chancery of the State of Delaware
against Asarco and Cyprus Amax and their respective Boards of Directors for
their breach of fiduciary duties including their refusals to consider and to
allow the shareholders of both companies to consider the Phelps Dodge proposal.

     In particular, Phelps Dodge alleges that Cyprus Amax and Asarco have
entered into an illegal merger agreement that purports to prohibit the companies
from taking any action or entering into any discussions relating to a takeover
proposal. In light of these provisions of the Asarco/Cyprus Amax Merger
Agreement, Asarco and Cyprus Amax are incapable of evaluating meaningfully the
Phelps Dodge proposal and cannot make informed recommendations to their
shareholders. Phelps Dodge has also challenged the termination or "break up" fee
payable to Asarco in certain circumstances as grossly excessive; that fee
amounts to more than 6% of Asarco's equity value as of July 15, 1999, the date
of the Asarco/Cyprus Amax merger agreement. Furthermore, the Asarco/Cyprus Amax
merger agreement includes corporate governance provisions that disenfranchise
shareholders by guaranteeing until 2002 the management positions of the chief
executive officers of Asarco and Cyprus Amax unless the positions are changed
with the approval of 75% of the full board.

                                       33
<PAGE>   41

     The complaints also allege that, in addition to their persistent refusals
to negotiate with Phelps Dodge, Asarco and Cyprus Amax set their shareholder
meetings and record dates to favor their own merger and have rewarded management
with lavish compensation and benefit packages. These and other efforts
undertaken by the companies amount to an attempt to favor and entrench
management at the expense of shareholders.

     Phelps Dodge is seeking injunctive relief to remedy these breaches of duty,
including court orders declaring that the boards of Asarco and Cyprus Amax
failed to make good faith efforts to obtain information about and adequately
consider the Phelps Dodge proposal and compelling the boards of those two
companies to consider the proposal and remove impediments preventing
consideration of the proposal.

EXTENSION, TERMINATION AND AMENDMENT

     We expressly reserve the right, in our sole discretion, at any time or from
time to time, to extend the period of time during which our offer remains open,
and we can do so by giving oral or written notice of such extension to the
exchange agent. If we decide to so extend our offer, we will make an
announcement to that effect no later than 9:00 A.M., New York City time, on the
next business day after the previously scheduled Expiration Date. We are not
making any assurance that we will exercise our right to extend our offer,
although we currently intend to do so until all conditions have been satisfied
or waived. During any such extension, all Asarco shares previously tendered and
not withdrawn will remain subject to the offer, subject to your right to
withdraw your Cyprus Amax shares. You should read the discussion under the
caption "Withdrawal Rights" for more details.

     Subject to the SEC's applicable rules and regulations, we also reserve the
right, in our sole discretion, at any time or from time to time, (a) to delay
acceptance for exchange of or, regardless of whether we previously accepted
Cyprus Amax shares for exchange, exchange of any Cyprus Amax shares pursuant to
our offer or to terminate our offer and not accept for exchange or exchange any
Cyprus Amax Shares not previously accepted for exchange, or exchanged, upon the
failure of any of the conditions of the offer to be satisfied and (b) to waive
any condition (other than the Phelps Dodge Stockholder Approval Condition, the
HSR Condition and the condition relating to the effectiveness of the
Registration Statement) or otherwise amend the offer in any respect, by giving
oral or written notice of such delay, termination or amendment to the exchange
agent and by making a public announcement. We will follow any extension,
termination, amendment or delay, as promptly as practicable, with a public
announcement. In the case of an extension, any such announcement will be issued
no later than 9:00 A.M., New York City time, on the next business day after the
previously scheduled Expiration Date. Subject to applicable law (including Rules
14d-4(c) and 14d-6(d) under the Exchange Act, which require that any material
change in the information published, sent or given to stockholders in connection
with the offer be promptly sent to stockholders in a manner reasonably designed
to inform stockholders of such change) and without limiting the manner in which
we may choose to make any public announcement, we assume no obligation to
publish, advertise or otherwise communicate any such public announcement other
than by making a release to the Dow Jones News Service.

     We confirm to you that if we make a material change in the terms of our
offer or the information concerning the offer, or if we waive a material
condition of the offer, we will extend the offer to the extent required under
the Exchange Act. If, prior to the Expiration Date, we change the percentage of
Cyprus Amax shares being sought or the consideration offered to you, that change
will apply to all holders whose Cyprus Amax shares are accepted for exchange
pursuant to our offer. If at the time notice of that change is first published,
sent or given to you, the offer is scheduled to expire at any time earlier than
the tenth business day from and including the date that such notice is first so
published, sent or given, we will extend the offer until the expiration of that
ten business-day period. For purposes of our offer, a "business day" means any
day other than a Saturday, Sunday or federal holiday and consists of the time
period from 12:01 A.M. through 12:00 midnight, New York City time.

     If Cyprus Amax agrees upon a negotiated merger with us, as we have proposed
several times, we may amend or terminate our offer without purchasing any Cyprus
Amax shares.

                                       34
<PAGE>   42

EXCHANGE OF CYPRUS AMAX SHARES; DELIVERY OF PHELPS DODGE COMMON STOCK

     Upon the terms and subject to the conditions of our offer (including, if
the offer is extended or amended, the terms and conditions of any such extension
or amendment), we will accept for exchange, and will exchange, Cyprus Amax
shares validly tendered and not withdrawn as promptly as practicable after the
Expiration Date. In addition, subject to applicable rules of the SEC, we
expressly reserve the right to delay acceptance for exchange or the exchange of
Cyprus Amax shares in order to comply with any applicable law. In all cases,
exchange of Cyprus Amax shares tendered and accepted for exchange pursuant to
the offer will be made only after timely receipt by the exchange agent of
certificates for those Cyprus Amax shares (or a confirmation of a book-entry
transfer of those Cyprus Amax shares in the exchange agent's account at The
Depository Trust Company (which we refer to as the "DTC")) a properly completed
and duly executed letter of transmittal (or a facsimile of that document) and
any other required documents.

     For purposes of the offer, we will be deemed to have accepted for exchange
Cyprus Amax shares validly tendered and not withdrawn as, if and when we notify
the exchange agent of our acceptance of the tenders of those Cyprus Amax shares
pursuant to the offer. The exchange agent will deliver Phelps Dodge common stock
in exchange for Cyprus Amax shares pursuant to the offer and cash instead of
fractional shares of Phelps Dodge common stock as soon as practicable after
receipt of such notice. The exchange agent will act as agent for tendering
stockholders for the purpose of receiving Phelps Dodge common stock and cash to
be paid instead of fractional shares of Phelps Dodge common stock from us and
transmitting such stock and cash to you. You will not receive any interest on
the cash to be given for fractional shares, even if there is a delay in making
the exchange.

     If we do not accept any tendered Cyprus Amax shares for exchange pursuant
to the terms and conditions of the offer for any reason, or if certificates are
submitted for more Cyprus Amax shares than are tendered, we will return
certificates for such unexchanged Cyprus Amax shares without expense to the
tendering stockholder or, in the case of Cyprus Amax shares tendered by
book-entry transfer of such Cyprus Amax shares into the exchange agent's account
at DTC pursuant to the procedures set forth below under the discussion entitled
"Procedure for Tendering," those Cyprus Amax shares will be credited to an
account maintained within DTC, as soon as practicable following expiration or
termination of the offer.

CASH INSTEAD OF FRACTIONAL SHARES OF PHELPS DODGE COMMON STOCK

     We will not issue certificates representing fractional shares of our common
stock pursuant to the offer. Instead, each tendering stockholder who would
otherwise be entitled to a fractional share of our common stock will receive
cash in an amount equal to such fraction (expressed as a decimal and rounded to
the nearest 0.01 of a share) multiplied by the closing price for shares of our
common stock on the NYSE Composite Tape on the date that we accept those Cyprus
Amax shares for exchange.

WITHDRAWAL RIGHTS

     Your tender of Cyprus Amax shares pursuant to the offer is irrevocable,
except that Cyprus Amax shares tendered pursuant to the offer may be withdrawn
at any time prior to the Expiration Date, and, unless we previously accepted
them pursuant to the offer, may also be withdrawn at any time after November 2,
1999.

     For your withdrawal to be effective, the exchange agent must receive from
you a written, telegraphic, telex or facsimile transmission notice of withdrawal
at one of its addresses set forth on the back cover of this prospectus, and your
notice must include your name, the number of Cyprus Amax shares to be withdrawn
and the name of the registered holder, if it is different from that of the
person who tendered those Cyprus Amax shares.

     A financial institution must guarantee all signatures on the notice of
withdrawal. Most banks, savings and loan associations and brokerage houses are
able to effect these signature guarantees for you. The financial institution
must be a participant in the Securities Transfer Agents Medallion Program, the
New York Stock Exchange Medallion Signature Program or the Stock Exchange
Medallion Program, any of which are an "eligible institution," unless those
Cyprus Amax shares have been tendered for the account of any eligible
institution. If Cyprus Amax shares have been tendered pursuant to the procedures
for book-entry tender discussed under the caption entitled "Procedure for
Tendering," any notice of withdrawal must specify the

                                       35
<PAGE>   43

name and number of the account at DTC to be credited with the withdrawn Cyprus
Amax shares and must otherwise comply with DTC's procedures. If certificates
have been delivered or otherwise identified to the exchange agent, the name of
the registered holder and the serial numbers of the particular certificates
evidencing the Cyprus Amax shares withdrawn must also be furnished to the
exchange agent, as stated above, prior to the physical release of such
certificates. We will decide all questions as to the form and validity
(including time of receipt) of any notice of withdrawal, in our sole discretion,
and our decision shall be final and binding. Neither we, the exchange agent, the
Information Agent, the Dealer Manager nor any other person will be under any
duty to give notification of any defects or irregularities in any notice of
withdrawal or will incur any liability for failure to give any such
notification. Any Cyprus Amax shares properly withdrawn will be deemed not to
have been validly tendered for purposes of our offer. However, you may retender
withdrawn Cyprus Amax shares by following one of the procedures discussed under
the caption entitled "Procedure for Tendering" at any time prior to the
Expiration Date.

     If you withdraw any of your Cyprus Amax shares, you automatically withdraw
the associated Cyprus Amax Rights. You may not withdraw Cyprus Amax Rights
unless you also withdraw the associated Cyprus Amax shares.

PROCEDURE FOR TENDERING

     For you to validly tender Cyprus Amax shares pursuant to the offer, (a) a
properly completed and duly executed letter of transmittal (or manually executed
facsimile of that document), along with any required signature guarantees, or an
agent's message in connection with a book-entry transfer, and any other required
documents, must be transmitted to and received by the exchange agent at one of
its addresses set forth on the back cover of this prospectus, and certificates
for tendered Cyprus Amax shares must be received by the exchange agent at such
address or those Cyprus Amax shares must be tendered pursuant to the procedures
for book-entry tender set forth below (and a confirmation of receipt of such
tender received (we refer to this confirmation below as a "Book-Entry
Confirmation")), in each case before the Expiration Date, or (b) you must comply
with the guaranteed delivery procedures set forth below.

     The term "agent's message" means a message, transmitted by DTC to, and
received by, the exchange agent and forming a part of a Book-Entry Confirmation,
which states that DTC has received an express acknowledgment from the
participant in DTC tendering the Cyprus Amax shares and, if applicable, Cyprus
Amax Rights, which are the subject of such Book-Entry Confirmation, that such
participant has received and agrees to be bound by the terms of the letter of
transmittal and that we may enforce that agreement against such participant.

     You must tender one Cyprus Amax Right for each Cyprus Amax share tendered
to effect a valid tender of Cyprus Amax shares, unless the Rights Plan Condition
has been satisfied or waived. Unless the Cyprus Amax Distribution Date occurs, a
tender of Cyprus Amax shares will constitute a tender of the associated Cyprus
Amax Rights. If the Cyprus Amax Distribution Date occurs and separate
certificates representing the Cyprus Amax Rights are distributed by Cyprus Amax
or the Rights Agent to holders of Cyprus Amax shares prior to the time that you
tender Cyprus Amax shares pursuant to the offer, certificates representing a
number of Cyprus Amax Rights equal to the number of Cyprus Amax shares tendered
must be delivered to the exchange agent, or, if available, a Book-Entry
Confirmation received by the exchange agent with respect thereto, in order for
such Cyprus Amax shares to be validly tendered. If the Cyprus Amax Distribution
Date occurs and separate certificates representing the Cyprus Amax Rights are
not distributed prior to the time that you tender Cyprus Amax shares pursuant to
the offer, Cyprus Amax Rights may be tendered prior to a stockholder's receipt
of the certificates for Cyprus Amax Rights by use of the guaranteed delivery
procedures described below. If Cyprus Amax Rights certificates are distributed
but are not available to you before Cyprus Amax shares are tendered pursuant to
the offer, a tender of Cyprus Amax shares constitutes an agreement by you to
deliver to the exchange agent pursuant to the guaranteed delivery procedures
described below, prior to the expiration of the period to be specified in the
notice of guaranteed delivery and the related letter of transmittal for delivery
of Cyprus Amax Rights certificates or a Book-Entry Confirmation for Cyprus Amax
Rights (we refer to this as the "Cyprus Amax Rights Delivery Period"), Cyprus
Amax Rights certificates representing a number of Cyprus Amax Rights equal to
the number of Cyprus Amax shares tendered. We

                                       36
<PAGE>   44

reserve the right to require receipt of such Cyprus Amax Rights certificates (or
a Book-Entry Confirmation with respect to such Cyprus Amax Rights) prior to
accepting Cyprus Amax shares for exchange.

     Nevertheless, we will be entitled to accept for exchange Cyprus Amax shares
that you tender prior to receipt of the Cyprus Amax Rights certificates required
to be tendered with such Cyprus Amax shares or a Book-Entry Confirmation with
respect to such Cyprus Amax Rights and either (a) subject to complying with
applicable rules and regulations of the SEC, withhold payment for such Cyprus
Amax shares pending receipt of the Cyprus Amax Rights certificates or a
Book-Entry Confirmation for those Cyprus Amax Rights or (b) exchange Cyprus Amax
shares accepted for exchange pending receipt of the Cyprus Amax Rights
certificates or a Book-Entry Confirmation for such Cyprus Amax Rights in
reliance upon the guaranteed delivery procedures described below. In addition,
after expiration of the Cyprus Amax Rights Delivery Period, we may instead elect
to reject as invalid a tender of Cyprus Amax shares with respect to which Cyprus
Amax Rights certificates or a Book-Entry Confirmation for an equal number of
Cyprus Amax Rights have not been received by the exchange agent. Any
determination by us to make payment for Cyprus Amax shares in reliance upon such
guaranteed delivery procedure or, after expiration of the Cyprus Amax Rights
Delivery Period, to reject a tender as invalid, shall be made, subject to
applicable law, in our sole and absolute discretion.

     The exchange agent will establish accounts with respect to the Cyprus Amax
shares at DTC for purposes of the offer within two business days after the date
of this prospectus, and any financial institution that is a participant in DTC
may make book-entry delivery of the Cyprus Amax shares by causing DTC to
transfer such Cyprus Amax shares into the exchange agent's account in accordance
with DTC's procedure for such transfer. However, although delivery of Cyprus
Amax shares may be effected through book-entry at DTC, the letter of transmittal
(or facsimile thereof), with any required signature guarantees, or an agent's
message in connection with a book-entry transfer, and any other required
documents, must, in any case, be transmitted to and received by the exchange
agent at one or more of its addresses set forth on the back cover of this
prospectus prior to the Expiration Date, or the guaranteed delivery procedures
described below. We cannot assure you, however, that book-entry delivery of
Cyprus Amax Rights will be available. If book-entry delivery is not available,
you must tender Cyprus Amax Rights by means of delivery of Cyprus Amax Rights
certificates or pursuant to the guaranteed delivery procedure set forth below.

     Signatures on all Letters of Transmittal must be guaranteed by an eligible
institution, except in cases in which Cyprus Amax shares are tendered either by
a registered holder of Cyprus Amax shares who has not completed either the box
entitled "Special Payment Instructions" or the box entitled "Special Delivery
Instructions" on the letter of transmittal or for the account of an eligible
institution.

     If the certificates for Cyprus Amax shares or Cyprus Amax Rights (if any)
are registered in the name of a person other than the person who signs the
letter of transmittal, or if certificates for unexchanged Cyprus Amax shares or
Cyprus Amax Rights (if any) are to be issued to a person other than the
registered holder(s), the certificates must be endorsed or accompanied by
appropriate stock powers, in either case signed exactly as the name or names of
the registered owner or owners appear on the certificates, with the signature(s)
on the certificates or stock powers guaranteed in the manner we have described
above.

     THE METHOD OF DELIVERY OF CYPRUS AMAX SHARE CERTIFICATES AND ALL OTHER
REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH DTC, IS AT YOUR OPTION AND RISK,
AND THE DELIVERY WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED BY THE EXCHANGE
AGENT. IF DELIVERY IS BY MAIL, WE RECOMMEND REGISTERED MAIL WITH RETURN RECEIPT
REQUESTED, PROPERLY INSURED. IN ALL CASES, YOU SHOULD ALLOW SUFFICIENT TIME TO
ENSURE TIMELY DELIVERY.

     TO PREVENT BACKUP FEDERAL INCOME TAX WITHHOLDING WITH RESPECT TO CASH
RECEIVED INSTEAD OF FRACTIONAL SHARES OF OUR COMMON STOCK, YOU MUST PROVIDE THE
EXCHANGE AGENT WITH YOUR CORRECT TAXPAYER IDENTIFICATION NUMBER AND CERTIFY
WHETHER YOU ARE SUBJECT TO BACKUP WITHHOLDING OF FEDERAL INCOME TAX BY
COMPLETING THE SUBSTITUTE FORM W-9 INCLUDED IN THE LETTER OF TRANSMITTAL. SOME
STOCKHOLDERS (INCLUDING, AMONG OTHERS, ALL CORPORATIONS AND SOME FOREIGN
INDIVIDUALS) ARE NOT SUBJECT TO THESE BACKUP WITHHOLDING AND REPORTING
REQUIREMENTS. IN ORDER FOR A FOREIGN INDIVIDUAL TO QUALIFY AS AN EXEMPT
RECIPIENT, THE STOCKHOLDER MUST SUBMIT A FORM W-8, SIGNED UNDER PENALTIES OF
PERJURY, ATTESTING TO THAT INDIVIDUAL'S EXEMPT STATUS.

                                       37
<PAGE>   45

     If you wish to tender Cyprus Amax shares pursuant to our offer and your
certificates are not immediately available or you cannot deliver the
certificates and all other required documents to the exchange agent prior to the
Expiration Date or cannot complete the procedure for book-entry transfer on a
timely basis, your Cyprus Amax shares may nevertheless be tendered, so long as
all of the following conditions are satisfied:

          (a) you make your tender by or through an eligible institution;

          (b) a properly completed and duly executed notice of guaranteed
     delivery, substantially in the form made available by us, is received by
     the exchange agent as provided below on or prior to the expiration date;
     and

          (c) the certificates for all tendered Cyprus Amax shares (or a
     confirmation of a book-entry transfer of such securities into the exchange
     agent's account at DTC as described above), in proper form for transfer,
     together with a properly completed and duly executed letter of transmittal
     (or facsimile thereof), with any required signature guarantees (or, in the
     case of a book-entry transfer, an agent's message) and all other documents
     required by the letter of transmittal are received by the exchange agent
     within three NYSE trading days after the date of execution of such notice
     of guaranteed delivery.

     You may deliver the notice of guaranteed delivery by hand or transmit it by
telegram, telex, facsimile transmission or mail to the exchange agent and you
must include a guarantee by an eligible institution in the form set forth in
that notice.

     In all cases, we will exchange Cyprus Amax shares tendered and accepted for
exchange pursuant to our offer only after timely receipt by the exchange agent
of certificates for Cyprus Amax shares (or timely confirmation of a book-entry
transfer of such securities into the exchange agent's account at DTC as
described above), properly completed and duly executed letter(s) of transmittal
(or facsimile(s) thereof), or an agent's message in connection with a book-entry
transfer, and any other required documents. Accordingly, you may be paid at
different times depending upon when the exchange agent actually receives
certificates for Cyprus Amax shares or confirmations of book-entry transfers of
those shares.

     By executing a letter of transmittal as set forth above, you irrevocably
appoint our designees as your attorneys-in-fact and proxies, each with full
power of substitution, to the full extent of your rights with respect to your
Cyprus Amax shares tendered and accepted for exchange by us and with respect to
any and all other Cyprus Amax shares and other securities issued or issuable in
respect of the Cyprus Amax shares on or after September 2, 1999. That
appointment is effective, and voting rights will be affected, when and only to
the extent that we deposit the shares of our common stock for Cyprus Amax shares
that you have tendered with the exchange agent. All such proxies shall be
considered coupled with an interest in the tendered Cyprus Amax shares and
therefore shall not be revocable. Upon the effectiveness of such appointment,
all prior proxies that you have given will be revoked, and you may not give any
subsequent proxies (and, if given, they will not be deemed effective). Our
designees will, with respect to the Cyprus Amax shares for which the appointment
is effective, be empowered, among other things, to exercise all of your voting
and other rights as they, in their sole discretion, deem proper at any annual,
special or adjourned meeting of Cyprus Amax's stockholders or otherwise. We
reserve the right to require that, in order for Cyprus Amax shares to be deemed
validly tendered, immediately upon our exchange of those Cyprus Amax shares, we
must be able to exercise full voting rights with respect to such Cyprus Amax
shares.

     We will determine questions as to the validity, form, eligibility
(including time of receipt) and acceptance for exchange of any tender of Cyprus
Amax shares, in our sole discretion, and our determination shall be final and
binding. We reserve the absolute right to reject any and all tenders of Cyprus
Amax shares that we determine are not in proper form or the acceptance of or
exchange for which may, in the opinion of our counsel, be unlawful. We also
reserve the absolute right to waive any of the conditions of our offer (other
than the HSR Condition, the Phelps Dodge Stockholder Approval Condition, the
condition relating to the effectiveness of the Registration Statement or, after
the Phelps Dodge Stockholder Approval Condition has been satisfied, the legal
opinion as to tax matters referred to below) or any defect or irregularity in
the tender of any Cyprus Amax shares. No tender of Cyprus Amax shares will be
deemed to have been validly made until all defects and irregularities in tenders
of Cyprus Amax shares have been cured or waived. Neither we, the exchange agent,
the Information Agent, the Dealer Manager nor any other person will be under any
duty to

                                       38
<PAGE>   46

give notification of any defects or irregularities in the tender of any Cyprus
Amax shares or will incur any liability for failure to give any such
notification. Our interpretation of the terms and conditions of our offer
(including the letter of transmittal and instructions thereto) will be final and
binding.

     The tender of Cyprus Amax shares and Cyprus Amax Rights (if any) pursuant
to any of the procedures described above will constitute a binding agreement
between us and you upon the terms and subject to the conditions of the offer.

MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS

     The following summarizes the anticipated material U.S. federal income tax
consequences of the acquisition of our common stock by you, pursuant to our
offer and the Phelps Dodge/Cyprus Amax merger contemplated by this prospectus.
This discussion applies only to a "U.S. Holder," which is a term that we explain
below. This summary does not address any tax consequences of our offer or the
Phelps Dodge/Cyprus Amax merger to U.S. Holders who exercise dissenters' rights,
if any. It applies only to shares of Cyprus Amax common stock held as capital
assets and does not address aspects of U.S. federal income tax that may apply to
holders that are subject to special tax rules, including:

     - insurance companies,

     - tax-exempt organizations,

     - financial institutions,

     - dealers in securities,

     - traders in securities who elect to apply a mark-to-market method of
       accounting,

     - foreign persons,

     - persons who acquired shares of Cyprus Amax common stock pursuant to an
       exercise of employee stock options or rights or otherwise as
       compensation, and

     - persons who hold shares of Cyprus Amax common stock as part of a
       straddle, conversion transaction, or construction sale.

Also, this summary does not address state, local or foreign tax consequences of
our offer or the Phelps Dodge/ Cyprus Amax merger. This summary is based on
current law, and future legislative, judicial or administrative changes or
interpretations, which may be retroactive, could affect the accuracy of this
discussion.

     For purposes of this discussion, a "U.S. Holder" means a holder of Cyprus
Amax shares that is

     - a citizen or resident of the United States,

     - a corporation organized in or under the laws of the United States or any
       political subdivision thereof or therein,

     - an estate the income of which is subject to U.S. federal income taxation
       regardless of its source, or

     - a trust if a U.S. court can exercise primary supervision over the
       administration of such trust and one or more U.S. persons has the
       authority to control all of the substantial decisions of such trust.

     WE STRONGLY ADVISE EACH U.S. HOLDER TO CONSULT HIS OR HER OWN TAX ADVISOR
AS TO THE U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE MERGER, INCLUDING THE
PARTICULAR FACTS AND CIRCUMSTANCES THAT MAY BE UNIQUE TO SUCH U.S. HOLDER, AND
AS TO ANY ESTATE, GIFT, STATE, LOCAL OR FOREIGN TAX CONSEQUENCES OF THE MERGER.

     In the opinion of Shearman & Sterling, special counsel to us, the exchange
of Cyprus Amax common stock for our common stock pursuant to our offer and the
Phelps Dodge/Cyprus Amax merger will be treated as a reorganization within the
meaning of Section 368(a) of the Internal Revenue Code (the "Code"). This
opinion is based on certain factual assumptions and representations including
that (i) none of Cyprus Amax, Phelps Dodge or any related party will acquire or
redeem, in connection with the transaction, shares of Phelps Dodge issued to
Cyprus Amax shareholders pursuant to our offer or the Phelps Dodge/Cyprus Amax
merger, to the extent inconsistent with the continuity of shareholder interest
requirements for corporate reorganizations; (ii) CAV Corporation will be merged
into Cyprus Amax, and shares of holders who exercise dissenters' rights, if any,
and the shares of Cyprus Amax Series A convertible preferred stock, will be
redeemed by

                                       39
<PAGE>   47

Cyprus Amax using its own funds; (iii) Cyprus Amax will continue its historic
business or will use a significant portion of its historic business assets in a
business; and (iv) our offer and the Phelps Dodge/Cyprus Amax merger will
generally be consummated as provided by this prospectus. The tax opinions
referred to herein will not be binding on the Internal Revenue Service (the
"IRS") or the courts, and the parties do not intend to request a ruling from the
IRS with respect to the merger. Accordingly, we cannot be certain that the IRS
will not challenge the conclusions reflected in those opinions or that a court
will not sustain such challenge.

     Assuming that the exchange of Cyprus Amax common stock for our common stock
pursuant to our offer and the Phelps Dodge/Cyprus Amax merger will be treated
for U.S. federal income tax purposes as an exchange pursuant to a plan of
reorganization within the meaning of Section 368(a) of the Code, as described
above, Shearman & Sterling is further of the opinion that the following U.S.
federal income tax consequences will result:

          (i) neither we nor Cyprus Amax will recognize any gain or loss with
     respect to the exchange of Cyprus Amax shares for our common stock as a
     result of our offer and the Phelps Dodge/Cyprus Amax merger;

          (ii) a U.S. Holder will not recognize any gain or loss on the exchange
     of all of such U.S. Holder's Cyprus Amax shares for our common stock,
     except as described below with respect to the receipt of cash instead of
     fractional shares of our common stock, and subject to the discussion below
     of the surrender of Cyprus Amax Rights that have become exercisable;

          (iii) the aggregate adjusted tax basis of shares of our common stock
     received by a U.S. Holder (including fractional shares of our common stock
     deemed received and redeemed as described below) will be the same as the
     aggregate adjusted tax basis of the Cyprus Amax shares exchanged therefor;

          (iv) the holding period of shares of our common stock (including the
     holding period of fractional shares of our common stock) received by a U.S.
     Holder will include the holding period of the Cyprus Amax shares exchanged
     therefor; and

          (v) a U.S. Holder of Cyprus Amax shares who receives cash instead of a
     fractional share of our common stock and who does not otherwise hold shares
     of our common stock will generally recognize capital gain or loss equal to
     the difference between the amount of cash received and the U.S. Holder's
     adjusted tax basis in such fractional share. The capital gain or loss will
     be long-term capital gain or loss if the U.S. Holder's holding period in
     the fractional share is more than one year. A U.S. Holder who separately
     holds shares of our common stock should consult his or her own tax advisor
     concerning the treatment of cash received for a fractional share.

     Because there is no specific binding authority dealing with securities such
as the Cyprus Amax Rights, Shearman & Sterling expresses no view with respect to
the U.S. federal income tax treatment of the Cyprus Amax Rights becoming
separately transferable apart from the Cyprus Amax shares, the redemption of the
Cyprus Amax Rights or the acquisition by us of the Cyprus Amax Rights.
Stockholders should consult their tax advisors as to the tax consequences of
transactions with respect to the Cyprus Amax Rights.

EFFECT OF OFFER ON MARKET FOR CYPRUS AMAX SHARES; REGISTRATION UNDER THE
EXCHANGE ACT

     The exchange of Cyprus Amax shares pursuant to our offer will reduce the
number of holders of Cyprus Amax shares and the number of Cyprus Amax shares
that might otherwise trade publicly and could adversely affect the liquidity and
market value of the remaining Cyprus Amax shares held by the public. Cyprus Amax
shares are listed and principally traded on the NYSE and are also listed on the
Philadelphia and Pacific Stock Exchanges. Depending on the number of Cyprus Amax
shares acquired pursuant to the offer, following consummation of the offer,
Cyprus Amax shares may no longer meet the requirements of such exchanges for
continued listing. For example, published guidelines of the NYSE indicate that
the NYSE would consider delisting the outstanding Cyprus Amax shares if, among
other things, (i) the number of publicly held Cyprus Amax shares (exclusive of
holdings of officers, directors and members of their immediate families and
other concentrated holdings of 10 percent or more) should fall below 600,000,
(ii) the number of record holders of

                                       40
<PAGE>   48

100 or more Cyprus Amax shares should fall below 1,200 or (iii) the aggregate
market value of publicly held shares should fall below $5 million.

     According to publicly available information, there were, as of August 18,
1999, approximately 90.5 million Cyprus Amax common shares outstanding.

     If such exchanges were to delist the Cyprus Amax shares, the market for
them could be adversely affected. It is possible that Cyprus Amax shares would
be traded on other securities exchanges or in the over-the-counter market, and
that price quotations would be reported by such exchanges, or through the
National Association of Securities Dealers, Inc., Automated Quotations System
("Nasdaq") or by other sources. The extent of the public market for the Cyprus
Amax shares and the availability of such quotations would, however, depend upon
the number of holders and/or the aggregate market value of the Cyprus Amax
shares remaining at such time, the interest in maintaining a market in the
Cyprus Amax shares on the part of securities firms, the possible termination of
registration of Cyprus Amax shares under the Exchange Act, as described below,
and other factors.

     The Cyprus Amax shares are presently "margin securities" under the
regulations of the Federal Reserve Board, which has the effect, among other
things, of allowing brokers to extend credit on the collateral of Cyprus Amax
shares. Depending on the factors similar to those described above with respect
to listing and market quotations, following consummations of the offer, the
Shares may no longer constitute "margin securities" for the purposes of the
Federal Reserve Board's margin regulations, in which event the Cyprus Amax
Shares would be ineligible as collateral for margin loans made by brokers. For a
description of the treatment of Shares in the Merger, you should refer to
"Purpose of the Offer; the Phelps Dodge/Cyprus Amax Merger."

     Cyprus Amax shares are currently registered under the Exchange Act. Cyprus
Amax can terminate that registration upon application to the SEC if the
outstanding shares are not listed on a national securities exchange and if there
are fewer than 300 holders of record of Cyprus Amax shares. Termination of
registration of the Cyprus Amax shares under the Exchange Act would reduce the
information that Cyprus Amax must furnish to its shareholders and to the SEC and
would make certain provisions of the Exchange Act, such as the short-swing
profit recovery provisions of Section 16(b) and the requirement of furnishing a
proxy statement in connection with shareholders meetings pursuant to Section
14(a) and the related requirement of furnishing an annual report to
shareholders, no longer applicable with respect to Cyprus Amax shares.
Furthermore, the ability of "affiliates" of Cyprus Amax and persons holding
"restricted securities" of Cyprus Amax to dispose of such securities pursuant to
Rule 144 under the Securities Act may be impaired or eliminated. If registration
of the shares under the Exchange Act were terminated, they would no longer be
eligible for Nasdaq reporting or for continued inclusion on the Federal Reserve
Board's list of "margin securities."

PURPOSE OF OUR OFFER; THE PHELPS DODGE/CYPRUS AMAX MERGER

     We are making the offer in order to acquire control of, and ultimately the
entire common equity interest in, Cyprus Amax. The offer is the first step in
our acquisition of Cyprus Amax, and is intended to facilitate the acquisition of
all Cyprus Amax shares. You will not have appraisal rights as a result of
consummation of our offer. We intend, as soon as practicable after consummation
of the offer, to seek to merge Cyprus Amax with and into a wholly owned
subsidiary. The purpose of the Phelps Dodge/Cyprus Amax merger is to acquire all
Cyprus Amax shares not tendered and exchanged pursuant to the offer. In the
Phelps Dodge/Cyprus Amax merger, each then outstanding Cyprus Amax share (except
for Cyprus Amax shares held in Cyprus Amax's treasury and Cyprus Amax shares
that we or one of our subsidiaries owns) would be converted into the right to
receive 0.3135 shares of Phelps Dodge common stock. The Phelps Dodge/Cyprus Amax
merger may be consummated pursuant to Section 253 of the DGCL. Under Section 253
of the DGCL, a parent corporation owning at least 90% of the outstanding shares
of each class of a subsidiary corporation may merge the subsidiary corporation
into itself without the approval of the stockholders of the parent corporation
or of the board of directors or stockholders of the subsidiary corporation.
Assuming the Minimum Tender Condition is satisfied and we consummate the offer,
we would have sufficient voting power to effect the Phelps Dodge/

                                       41
<PAGE>   49

Cyprus Amax merger under Section 251 of the DGCL without the vote of any other
stockholder of Cyprus Amax.

     Although stockholders do not have appraisal rights as a result of the
offer, if the Phelps Dodge/Cyprus Amax merger is consummated pursuant to Section
253 of the DGCL, Cyprus Amax stockholders at the time of the Phelps Dodge/Cyprus
Amax merger who do not vote in favor of the Phelps Dodge/Cyprus Amax merger will
have the right under the DGCL to dissent and demand appraisal of their Cyprus
Amax shares in accordance with Section 262 of the DGCL. Under Section 262,
dissenting stockholders who comply with the applicable statutory procedures will
be entitled to receive a judicial determination of the fair value of their
Cyprus Amax shares (exclusive of any element of value arising from the
accomplishment or expectation of the Phelps Dodge/Cyprus Amax merger) and to
receive payment of such fair value in cash, together with a fair rate of
interest, if any. In Cede & Co. and Cinerama, Inc. v. Technicolor, Inc., the
Supreme Court of the State of Delaware construed Section 262 of the DGCL and
held that the "accomplishment or expectation" exclusion from the calculation of
fair value set forth in the preceding sentence is narrow and is designed to
eliminate use of pro forma data and projections of a speculative variety
relating to the completion of a merger. The court held that it is appropriate to
include in the calculation of fair value any known elements of value, including
those elements of value which exist on the date of the merger because of a
majority acquiror's interim action in a two-step cash-out transaction. We cannot
assure you as to the methodology a court would use to determine fair value or
how a court would select which of the elements of value are to be included in
such a determination. Any such judicial determination of the fair value of
Cyprus Amax shares could be based upon factors other than, or in addition to,
the price per Cyprus Amax share to be paid in the Phelps Dodge/ Cyprus Amax
merger or the market value of the Cyprus Amax shares. The value so determined
could be more or less than the price per Cyprus Amax share to be paid in the
Phelps Dodge/Cyprus Amax merger.

     Even if the Minimum Tender Condition is satisfied and the offer is
consummated, we reserve the right to effect the Phelps Dodge/Cyprus Amax merger
pursuant to Section 251 of the DGCL. Assuming the Cyprus Amax shares remain
listed on a national securities exchange or are then quoted through NASDAQ or
held of record by more than 2,000 holders, the holders of Cyprus Amax shares
will not have appraisal rights if the Phelps Dodge/Cyprus Amax merger is
consummated pursuant to Section 251 of the DGCL. However, if the Phelps
Dodge/Cyprus Amax merger is so consummated, and if, on the date fixed to
determine stockholders entitled to vote on the Phelps Dodge/Cyprus Amax merger,
the Cyprus Amax shares are not listed on a national securities exchange or
quoted through NASDAQ or held of record by more than 2,000 holders, you may have
appraisal rights pursuant to the provisions of Section 262 of the DGCL as
described above.

     Rule 13e-3 of the General Rules and Regulations under the Exchange Act,
which we do not believe would apply to the Phelps Dodge/Cyprus Amax merger if
the Phelps Dodge/Cyprus Amax merger occurred within one year of consummation of
our offer, would require, among other things, that some financial information
concerning Cyprus Amax, and some information relating to the fairness of the
proposed transaction and the consideration offered to stockholders of Cyprus
Amax therein, be filed with the SEC and disclosed to you prior to consummation
of the Phelps Dodge/Cyprus Amax merger.

     In addition, we reserve the right to acquire, following the consummation or
termination of our offer, additional Cyprus Amax shares through open market
purchases, privately negotiated transactions, a tender offer or exchange offer,
or otherwise, upon such terms and at such prices as we decide, which may be more
or less favorable than those of the offer. We and our affiliates also reserve
the right to dispose of any or all Cyprus Amax shares acquired by us pursuant to
the offer or otherwise, upon such terms and at such prices as we shall
determine.

     It is our current intention that, following consummation of our offer, we
would cause Cyprus Amax to redeem all 4,664,000 shares of its Series A
Convertible Preferred Stock, which are redeemable at Cyprus Amax's option. Any
final decision as to whether to redeem those shares will be made in light of
circumstances existing at that time.

     Upon consummation of our offer, we intend to take appropriate actions to
optimize and rationalize the combined entities' assets, operations, exploration
activities, management, personnel general and administrative functions and
corporate structure. Except as we have otherwise discussed elsewhere in this
prospectus, we do not have any plans or proposals right now that would result in
an extraordinary corporate transaction, such as a

                                       42
<PAGE>   50

merger, reorganization or liquidation, or sale of a material amount of assets,
involving Cyprus Amax or any of its subsidiaries, or any material changes in
Cyprus Amax's corporate structure or business, or any change in its management.
Cyprus Amax has not given us any access to its books and records, however, so we
might decide upon such changes once we complete such a review.

     As described under the caption entitled "Reasons for the Proposed
Combination" upon consummation of the Phelps Dodge/Cyprus Amax merger, we expect
to realize substantial cost savings in both administrative and operational
areas.

     Upon consummation of our offer, we may also elect or seek the election of
nominees of our choice to Cyprus Amax's Board of Directors.

CONDITIONS OF OUR OFFER

     Our offer is subject to a number of conditions, which are described below:

  MINIMUM TENDER CONDITION

     There must be validly tendered, prior to the expiration of the offer and
not withdrawn, a number of Cyprus Amax shares which will constitute at least a
majority of the total number of outstanding Cyprus Amax shares on a fully
diluted basis (as though all options or other securities convertible into or
exercisable or exchangeable for Cyprus Amax shares had been so converted,
exercised or exchanged) as of the date that we accept the Cyprus Amax shares for
exchange pursuant to our offer.

  RIGHTS PLAN CONDITION

     This condition would be satisfied if the board of directors of Cyprus Amax
redeems the Cyprus Amax Rights or amends the Cyprus Amax Rights Agreement so
that the Cyprus Amax Rights would not be triggered by the offer and the Phelps
Dodge/Cyprus Amax merger, or a court of competent jurisdiction invalidates the
Cyprus Amax Rights Agreement.

  DGCL 203 CONDITION

     This condition would be satisfied if either: (a) the board of directors of
Cyprus Amax approves the offer for purposes of Section 203 of the DGCL or (b) we
acquire 85% or more of the voting stock of Cyprus Amax pursuant to the offer.

     Section 203 of the DGCL, in general, prohibits a Delaware corporation such
as Cyprus Amax from engaging in a "business combination" (as defined in Section
203) with an "interested stockholder" (as defined in Section 203) for a period
of three years following the date that such person became an interested
stockholder unless (a) prior to the date that such person became an interested
stockholder, the board of directors of the corporation approved either the
business combination or the transaction that resulted in the stockholder
becoming an interested stockholder, (b) upon consummation of the transaction
that resulted in the stockholder becoming an interested stockholder, the
interested stockholder owned at least 85% of the voting stock of the corporation
outstanding at the time the transaction commenced, excluding stock held by
directors who are also officers of the corporation and employee stock plans that
do not provide employees with the right to determine confidentially whether
shares held subject to the plan will be tendered in a tender or exchange offer,
(c) the business combination is proposed prior to the consummation or
abandonment of and subsequent to the public announcement of a proposed
transaction which (i) constitutes a merger or consolidation of the corporation,
(ii) is with or by a person who either was not an interested stockholder during
the previous three years or who became an interested stockholder with the
approval of the corporation's board of directors or during the period described
in Section 203(b)(7) of the DGCL and (iii) is approved or not opposed by a
majority of the board of directors then in office who were directors prior to
any person becoming an interested stockholder during the previous three years,
or (d) on or subsequent to the date such person became an interested
stockholder, the business combination is approved by the board of directors of
the corporation and authorized at a meeting of stockholders, and not by written
consent, by the affirmative vote of the holders of at least 66 2/3% of the
outstanding voting stock of the corporation not owned by the interested
stockholder.

                                       43
<PAGE>   51

  FAIR PRICE CONDITION

     This condition, which would limit the ability of Phelps Dodge to enter into
the Phelps Dodge/Cyprus Amax merger if the offer is consummated, would be
satisfied if either (a) the board of directors of Cyprus Amax approves the
Phelps Dodge/Cyprus Amax Merger for purposes of Article Sixth of the Cyprus Amax
Restated Certificate of Incorporation or (b) we acquire 75% or more of the
outstanding voting stock of Cyprus Amax.

  PHELPS DODGE STOCKHOLDER APPROVAL CONDITION

     Pursuant to the rules of the NYSE (on which our common stock is listed),
the issuance of our common stock pursuant to the offer and the Phelps
Dodge/Cyprus Amax merger must be approved by the holders of a majority of the
shares voted at a meeting of such holders at which the total number of votes
cast represents over 50% in interest of all shares of our common stock entitled
to vote on the proposal, because the number of shares of our common stock to be
issued will be equal to or in excess of 20% of the shares outstanding prior to
such issuance. We intend to seek this approval at a special stockholders meeting
that we intend to hold as soon as practicable after the effective date of our
registration statement.

  HSR CONDITION

     Our offer is conditioned upon the waiting period (and any extension
thereof) applicable to the offer under the HSR Act having expired or been
terminated.

     Under the HSR Act, and the rules that have been promulgated thereunder (the
"Rules"), some acquisitions may not be consummated unless information has been
furnished to the Antitrust Division of the Department of Justice (the "Antitrust
Division") and the Federal Trade Commission (the "FTC") and some waiting period
requirements have been satisfied. The acquisition of Cyprus Amax shares pursuant
to our offer is subject to the HSR Act. We will file with the Antitrust Division
and the FTC a Hart-Scott-Rodino Notification and Report Form with respect to our
offer. Under the applicable provisions of the HSR Act, the purchase of Cyprus
Amax shares under the offer cannot be consummated until the expiration or early
termination of a waiting period that begins after we file that Report Form. The
initial waiting period under the HSR Act is 30 days. Either the FTC or the
Antitrust Division may issue a request for additional information or documentary
material, which will extend the waiting period until 20 days after compliance
with such request. Federal and state antitrust enforcement agencies frequently
scrutinize under the antitrust laws transactions such as our acquisition of
Cyprus Amax shares pursuant to our offer. At any time before or after we acquire
Cyprus Amax shares, any such agency could take such action under the antitrust
laws as it deems necessary or desirable in the public interest, including
seeking to enjoin the acquisition of Cyprus Amax shares pursuant to the offer or
otherwise or seeking divestiture of Cyprus Amax shares acquired by us or
divestiture of assets of Phelps Dodge and/or Cyprus Amax. Private parties may
also bring legal action under the antitrust laws under some circumstances.
Phelps Dodge, Asarco and Cyprus Amax conduct operations in a number of
jurisdictions where other regulatory filings or approvals may be required or
advisable in connection with the completion of our offer. See "-- Other
Conditions of Our Offer."

     Some large Cyprus Amax stockholders (those that would receive more than $15
million in Phelps Dodge shares or, in certain cases, more than 10% of Phelps
Dodge's shares) may be required to make separate filings with the FTC and
Antitrust Division under the HSR Act and the Rules in conjunction with the
receipt of shares of our common stock. If you must make such a filing, you will
then be required to observe applicable waiting periods under the HSR Act and the
Rules before receiving shares of Phelps Dodge common stock. If you are obligated
to make such a filing, we will deposit the shares of our common stock to be
exchanged, pursuant to the Rules, pending expiration or early termination of the
waiting period.

     Although no assurances can be given, we anticipate that the HSR Condition
will be satisfied on a timely basis.

  OTHER CONDITIONS OF OUR OFFER

     Notwithstanding any other provision of our offer, we shall not be required
to accept for exchange or exchange any Cyprus Amax shares, may postpone the
acceptance for exchange of or exchange for tendered Cyprus Amax shares, and may,
in our sole discretion, terminate or amend the offer as to any Cyprus Amax
                                       44
<PAGE>   52

shares not then exchanged (a) if at the expiration date, any of the Minimum
Tender Condition, the Rights Plan Condition, the DGCL 203 Condition, the Fair
Price Condition, the Phelps Dodge Stockholder Approval Condition or the HSR
Condition has not been satisfied or, with respect to the Minimum Tender
Condition, the Rights Plan Condition, the DGCL 203 Condition, or the Fair Price
Condition, waived, or (b) if on or after the date of this prospectus and at or
prior to the expiration date, any of our other conditions are not satisfied.
Those conditions are as follows:

          (a) The shares of our common stock which shall be issued to Cyprus
     Amax stockholders in the offer and the Phelps Dodge/Cyprus Amax merger have
     been authorized for listing on the NYSE, subject to official notice of
     issuance;

          (b) The Registration Statement shall have become effective under the
     Securities Act, and no stop order suspending the effectiveness of the
     Registration Statement shall have been issued nor shall there have been
     proceedings for that purpose initiated or threatened by the SEC and we
     shall have received all necessary state securities law or "blue sky"
     authorizations;

          (c) No temporary restraining order, preliminary or permanent
     injunction or other order or decree issued by any court or agency of
     competent jurisdiction or other legal restraint or prohibition preventing
     the consummation of the offer or any of the other transactions contemplated
     by this prospectus shall be in effect; no statute, rule, regulation, order,
     injunction or decree shall have been enacted, entered, promulgated or
     enforced by any court, administrative agency or commission or other
     governmental authority or instrumentality which prohibits, restricts or
     makes illegal the consummation of our offer; nor shall there have been a
     failure to obtain any required consent or approval under foreign laws or
     regulations which would prohibit the consummation of the offer or would
     have a material adverse effect on us or on Cyprus Amax;

          (d) There shall not be pending any suit, action or proceeding by any
     governmental entity (a) challenging the offer, seeking to restrain or
     prohibit the consummation of the offer or seeking to obtain from Cyprus
     Amax or us any damages that are material in relation to Cyprus Amax and its
     subsidiaries taken as a whole, (b) seeking to prohibit or limit the
     ownership or operation by Cyprus Amax or us or any of our subsidiaries of
     any material portion of the business or assets of Cyprus Amax or us or any
     of our subsidiaries or to compel Cyprus Amax or us or any of our
     subsidiaries to dispose of or hold separate any material portion of the
     business or assets of Cyprus Amax or us or any of our subsidiaries, as a
     result of the offer, (c) seeking to prohibit us from effectively
     controlling in any material respect the business or operations of Cyprus
     Amax or (d) which otherwise is reasonably likely to have a material adverse
     effect on us or Cyprus Amax;

          (e) Cyprus Amax stockholders have voted to reject the Asarco/Cyprus
     Amax merger, or the Asarco/Cyprus Amax Merger Agreement is otherwise
     terminated; and

          (f) We receive the opinion of Shearman & Sterling as to tax matters,
     as outlined above.


          (g) The representations and warranties of Cyprus Amax in the
     Asarco/Cyprus Amax Merger Agreement shall be true and correct (without
     giving effect to any qualification as to "materiality" or "Material Adverse
     Effect" set forth therein) as of the date of this prospectus and as of the
     expiration date as though made on and as of the date of this prospectus and
     the expiration date except where the failure of such representations and
     warranties to be so true and correct would not reasonably be expected to
     have, individually or in the aggregate, a Material Adverse Effect (as
     defined therein) on Cyprus Amax.


     The conditions to the offer are substantially identical to the conditions
to each of Asarco and Cyprus Amax to effect the mergers under the Asarco/Cyprus
Amax Merger Agreement except that:

          (a) Phelps Dodge does not have to accept for exchange or exchange any
     Cyprus Amax shares pursuant to the offer, or can terminate or amend the
     offer if the stockholders of Cyprus Amax have approved the Asarco/Cyprus
     Amax Merger Agreement.


          (b) Cyprus Amax does not have to effect the Asarco/Cyprus Amax mergers
     unless it receives an opinion of its counsel to the effect that the Cyprus
     Amax merger, taken together with the Asarco merger, will qualify as a
     transaction described in Section 351 of the IRS Code.


                                       45
<PAGE>   53

          (c) Neither Asarco nor Cyprus Amax must effect the Asarco-Cyprus Amax
     mergers if either party fails to receive shareholder approval.

          (d) Neither Asarco nor Cyprus Amax must effect the Asarco-Cyprus Amax
     mergers if either party does not receive "comfort" letters from their
     respective independent accountants.

          (e) Neither Asarco nor Cyprus Amax must effect the Asarco-Cyprus Amax
     mergers unless the other party has performed in all material respects its
     obligations required to be performed by it under the Asarco-Cyprus Amax
     Merger Agreement at or prior to the closing of the Asarco-Cyprus Amax
     mergers, and each of Asarco and Cyprus Amax must receive a certificate from
     the other party's Chairman of the Board, Chief Executive Officer and
     President, certifying to that effect.

          (f) Phelps Dodge does not have to accept for exchange or exchange any
     Cyprus Amax shares pursuant to the offer if the Minimum Tender Condition,
     the Rights Plan Condition, the Phelps Dodge Stockholder Approval Condition,
     the Fair Price Condition, the DGCL 203 Condition and the HSR Condition are
     not satisfied.

     The foregoing conditions are solely for our benefit and we may assert them
regardless of the circumstances giving rise to any such conditions (including
any action or inaction by us). We may waive these conditions in whole or in part
(other than the Phelps Dodge Stockholder Approval Condition, the HSR Condition,
the condition relating to effectiveness of the Registration Statement and, after
the Phelps Dodge Stockholder Approval Condition has been satisfied, the
condition relating to the legal opinion as to tax matters referred to above).
The determination as to whether any condition has been satisfied shall be in our
judgment and will be final and binding on all parties. The failure by us at any
time to exercise any of the foregoing rights shall not be deemed a waiver of any
such right and each such right shall be deemed a continuing right which may be
asserted at any time and from time to time. Notwithstanding the fact that we
reserve the right to assert the failure of a condition following acceptance for
exchange but prior to exchange in order to delay exchange or cancel its
obligation to exchange properly tendered Cyprus Amax shares, we will either
promptly exchange such Cyprus Amax shares or promptly return such Cyprus Amax
shares.

RELATIONSHIPS WITH CYPRUS AMAX

     Except as set forth herein, neither we nor, to the best of our knowledge,
any of our directors, executive officers or other affiliates has any contract,
arrangement, understanding or relationship with any other person with respect to
any securities of Cyprus Amax, including, but not limited to, any contract,
arrangement, understanding or relationship concerning the transfer or the voting
of any such securities, joint ventures, loan or option arrangements, puts or
calls, guaranties of loans, guaranties against loss or the giving or withholding
of proxies. Except as described herein, there have been no contacts,
negotiations or transactions since January 1, 1996, between us or, to the best
of our knowledge, any of our directors, executive officers or other affiliates
on the one hand, and Cyprus Amax or its affiliates, on the other hand,
concerning a merger, consolidation or acquisition, a tender offer or other
acquisition of securities, an election of directors, or a sale or other transfer
of a material amount of assets. Except as set forth herein, neither we, nor, to
the best of our knowledge, any of our directors, executive officers or other
affiliates has since January 1, 1996 had any transaction with Cyprus Amax or any
of its executive officers, directors or affiliates that would require disclosure
under the rules and regulations of the SEC applicable to the offer.

     Shares of Apache Nitrogen Products, Inc. are held 49.2% by Phelps Dodge,
and 11.42% by Cyprus Miami Corporation and 0.66% by Cyprus Mines Corporation,
both subsidiaries of Cyprus Amax. Apache Nitrogen has contracts with several
affiliates of Cyprus Amax, including the shareholders of Apache Nitrogen and
Cyprus Sierrita Corporation, Cyprus Bagdad Copper Corporation, Cyprus Tohono
Corporation and Cyprus Mineral Park Corporation, for the sale of ANFO, an
explosive mixture. Sales to Phelps Dodge annually range from $16-17 million, and
sales to Cyprus Amax annually range from $6-8 million.

FEES AND EXPENSES

     We have retained Innisfree M&A Incorporated to act as the information agent
in connection with our offer. The information agent may contact holders of
Cyprus Amax shares by mail, telephone, telex, telegraph and personal interviews
and may request brokers, dealers and other nominee stockholders to forward our
offer

                                       46
<PAGE>   54

materials to beneficial owners of Cyprus Amax shares. The information agent will
be paid a customary fee for such services, plus reimbursement of out-of-pocket
expenses, and we will indemnify the information agent against certain
liabilities and expenses in connection with our offer, including liabilities
under federal securities laws.

     Pursuant to a letter agreement dated August 16, 1999 (the "Letter
Agreement"), Morgan Stanley & Co. Incorporated ("Morgan Stanley") is providing
certain financial advisory services to Phelps Dodge in connection with our
offer. Under the terms of the Letter Agreement, Phelps Dodge has agreed to pay
Morgan Stanley for its financial advisory services, including its services as
Dealer Manager, in connection with our offer a financial advisory fee of (i)
$11.0 million per acquired company if Phelps Dodge acquires control, as defined
in the Letter Agreement, of Asarco or Cyprus Amax, with certain amounts payable
upon the announcement of defined events, and (ii) an additional $2.0 million if
Phelps Dodge acquires either Asarco or Cyprus Amax within two years of acquiring
the other. Phelps Dodge has also agreed to reimburse Morgan Stanley for its
out-of-pocket expenses, including the fees and expenses of its legal counsel
incurred in connection with this engagement, and has agreed to indemnify each of
Morgan Stanley and certain related persons and entities against certain
liabilities and expenses in connection with Morgan Stanley's engagement,
including certain liabilities under federal securities laws.

     In addition to the fees to be received by Morgan Stanley in connection with
its engagement as financial advisor to Phelps Dodge, Morgan Stanley has in the
past rendered various investment banking and financial advisory services for
Phelps Dodge for which it has received customary compensation.

     We will not pay any fees or commissions to any broker, dealer or other
persons (other than the dealer manager and the information agent) for soliciting
tenders of Cyprus Amax shares pursuant to our offer.

ACCOUNTING TREATMENT

     The merger of Cyprus Amax into Phelps Dodge would be accounted for under
the purchase method of accounting under U.S. generally accepted accounting
principles, which means that Cyprus Amax's results of operations will be
included with ours from the closing date and its consolidated assets and
liabilities will be recorded at their fair values at the same date.

STOCK EXCHANGE LISTINGS

     Our common stock is listed on the NYSE, as well as on the Boston,
Cincinnati, Philadelphia, Pacific and Chicago Stock Exchanges. We will make an
application to list on the NYSE the common stock that we will issue pursuant to
our offer and the subsequent Phelps Dodge/Cyprus Amax merger. As described above
under "The Offer -- Conditions of Our Offer -- Phelps Dodge Stockholder Approval
Condition," pursuant to the rules of the NYSE, the issuance of our common stock
in the offer and the subsequent Phelps Dodge/Cyprus Amax merger must be approved
by the holders of a majority of the Phelps Dodge common stock voting at a
meeting at which the total number of votes cast represents over 50% in interest
of all shares of our common stock entitled to vote on the proposal.

                                       47
<PAGE>   55

                                 THE COMPANIES

PHELPS DODGE CORPORATION

     Phelps Dodge Corporation is among the world's largest producers of copper,
carbon black and magnet wire, and is the world's largest producer of
continuous-cast copper rod. Phelps Dodge comprises two divisions: (i) Phelps
Dodge Mining Company and (ii) Phelps Dodge Industries.

     - Phelps Dodge Mining Company is a business segment that includes our
       worldwide copper operations from mining through rod production, marketing
       and sales, other mining operations and investments, and worldwide mineral
       exploration and development programs.

     - Phelps Dodge Industries includes our specialty chemicals segment, our
       wire and cable segment, and, until they were sold in 1998, our wheel and
       rim operations.

     In 1998, Phelps Dodge Mining Company produced 874,000 tons of copper for
our account from worldwide mining operations, and an additional 178,700 tons of
copper for the accounts of our minority interest partners. Gold, silver,
molybdenum, copper chemicals and sulfuric acid are by-products of our copper
operations. Production of copper for our own account from our U.S. operations
constituted approximately 33 percent of the copper mined in the United States in
1998. Much of our U.S. cathode copper production, together with additional
copper purchased from others, is used to produce continuous-cast copper rod, the
basic feed for the electrical wire and cable industry.

     Our international mining interests include Candelaria, a major copper mine
in Chile, and other operations and investments in Chile and Peru. These
operations produce a variety of metals and minerals including copper, gold,
silver, and zinc. We also explore for metals and minerals throughout the world.

     In addition to our mining interests, we produce engineered products
principally for the global energy, telecommunications, transportation and
specialty chemicals sectors through Phelps Dodge Industries. Specialty chemicals
are produced at Columbian Chemicals Company which is among the world's largest
producers of carbon black. Carbon black is a reinforcing agent in natural and
synthetic rubber that increases the service life of tires, hoses, belting and
other products for the rubber industry. We also produce specialty carbon black
for other industrial applications such as pigments for printing, coatings,
plastics and other non-rubber applications.

     Our wire and cable segment comprises Phelps Dodge Magnet Wire Company and
its subsidiaries and Phelps Dodge International Corporation and its affiliates.
This segment produces wire and cable products and specialty conductors at U.S.
and international operations. Phelps Dodge Magnet Wire Company produces magnet
wire and other copper products for sale principally to original equipment
manufacturers for use in electrical motors, generators, transformers and other
products. Phelps Dodge International Corporation manufactures telecommunication
and energy cables and specialty conductors.

     Our company employed 13,193 people on June 30, 1999.

     We have our principal executive offices at 2600 North Central Avenue,
Phoenix, Arizona 85004-3014 (telephone number (602) 234-8100).

ASARCO INCORPORATED

     Asarco, a New Jersey corporation organized in 1899, is one of the world's
leading producers of copper. Asarco also produces specialty chemicals and
aggregates. Asarco's copper business includes integrated mining, smelting and
refining operations in North America and in Peru through its 54.3% owned
subsidiary, Southern Peru Copper Corporation. Enthone-OMI, Inc., a wholly owned
subsidiary, operates a worldwide specialty chemicals business focused on
functional and decorative coatings for the electronics and metal finishing
industries. American Limestone Company, a wholly owned subsidiary, produces
construction aggregates, ready-mixed concrete and agricultural limestone. Asarco
also operates a custom lead smelting business, a silver mining business, a zinc
mining business and a specialty metals business. Asarco owns Encycle, Inc.,

                                       48
<PAGE>   56

which operates a waste recycling facility and Hydrometrics, an environmental
consulting and construction firm. As of June 30, 1999, Asarco and its
subsidiaries employed approximately 10,100 employees.

     Asarco has its principal executive offices at 180 Maiden Lane, New York,
New York 10038 (telephone number (212) 510-2000).

CYPRUS AMAX MINERALS COMPANY

     Cyprus Amax, a Delaware corporation organized in 1969, is a major mining
company engaged, directly or through its subsidiaries and affiliates, in the
exploration for and extraction, processing, and marketing of mineral resources.
Cyprus Amax is a leading copper producer, the world's largest producer of
molybdenum, and has a significant position in gold via its 30% interest in
Kinross Gold Corporation. Cyprus Amax sold certain eastern and midwestern coal
operations in June of 1998 and sold its lithium business in October of 1998.
Cyprus Amax sold its remaining U.S. coal operations in June of 1999. Cyprus Amax
still holds its Australian coal properties. As of June 30, 1999, Cyprus Amax and
its subsidiaries employed approximately 4,600 employees.

     Cyprus Amax has its principal executive offices at 9100 East Mineral
Circle, Englewood, Colorado 80112 (telephone number (212) 643-500).

                                       49
<PAGE>   57

                          MARKET PRICES AND DIVIDENDS

     The Phelps Dodge common shares are listed and principally traded on the
NYSE under the symbol "PD". The Asarco common shares are listed and principally
traded on the NYSE under the symbol "AR". The Cyprus Amax common shares are
listed and principally traded on the NYSE under the symbol "CYM". The following
table sets forth, for the periods indicated, (1) the high and low last reported
prices per Phelps Dodge share, Asarco share and Cyprus Amax share, in each case
as reported on the New York Stock Exchange Composite Transaction Tape; and (2)
the cash dividends per Phelps Dodge share, Asarco share and Cyprus Amax share.
<TABLE>
<CAPTION>
                                 PHELPS DODGE COMMON STOCK                  ASARCO COMMON STOCK
                             ----------------------------------     -----------------------------------
                             HIGH          LOW         DIVIDEND     HIGH          LOW          DIVIDEND
                             ----          ---         --------     ----          ---          --------
<S>                          <C>           <C>         <C>          <C>           <C>          <C>
1997
First Quarter..............  $79           $68          $0.50       $32 1/2       $25 1/8       $0.20
Second Quarter.............   89 5/8        70 1/4       0.50        32 1/2        26 1/8        0.20
Third Quarter..............   87 15/16      75 1/16      0.50        34            30            0.20
Fourth Quarter.............   79 13/16      59 7/8       0.50        31 7/8        21 3/4        0.20
1998
First Quarter..............  $69 1/4       $58 1/16     $0.50       $26 3/4       $20 1/2       $0.20
Second Quarter.............   71 3/4        56 1/8       0.50        27 13/16      21 3/8        0.20
Third Quarter..............   62 9/16       43 7/8       0.50        24            15 7/16       0.20
Fourth Quarter.............   61 3/4        49 9/16      0.50        23            14 7/8        0.10
1999
First Quarter..............  $61 5/16      $41 7/8      $0.50       $18 3/8       $13 11/16     $0.05
Second Quarter.............   70 5/8        48 7/8       0.50        19 1/4        13 7/16       0.05
Third Quarter (through
  August 31)...............   66 3/4        55 15/16     0.50        22 5/8        17 1/2        0.05

<CAPTION>
                                  CYPRUS AMAX COMMON STOCK
                             -----------------------------------
                             HIGH          LOW          DIVIDEND
                             ----          ---          --------
<S>                          <C>           <C>          <C>
1997
First Quarter..............  $24 7/8       $21 1/4       $0.20
Second Quarter.............   26 3/8        21 5/8        0.20
Third Quarter..............   26 13/16      22 3/8        0.20
Fourth Quarter.............   25            14 7/16       0.20
1998
First Quarter..............  $17 7/8       $14           $0.20
Second Quarter.............   17 7/8        13            0.20
Third Quarter..............   13 13/16       9 3/16       0.20
Fourth Quarter.............   14 3/8         9            0.20
1999
First Quarter..............  $13 1/8       $ 9 3/8       $0.20
Second Quarter.............   16 1/16       11 3/8        0.05
Third Quarter (through
  August 31)...............   17 13/16      12 7/8        0.05
</TABLE>

     On August 19, 1999, the last full trading day before Phelps Dodge publicly
announced its proposal to combine with Asarco and Cyprus Amax, the last reported
closing prices per Phelps Dodge common share, Asarco common share and Cyprus
Amax common share were $58 9/16, $18 7/16 and $14 1/2, respectively. On August
31, 1999, the most recent practicable date prior to the filing of this
prospectus, the last reported closing prices per Phelps Dodge common share,
Asarco common share and Cyprus Amax common share were $55 15/16, $20 7/8 and
$16 15/16, respectively. We urge you to obtain current market quotations before
making any decision with respect to our offer.

     On August 19, 1999, the last full trading day before Phelps Dodge publicly
announced its proposal to combine with Asarco and Cyprus Amax, the closing
prices per Asarco common share and Cyprus Amax common share on an equivalent
share basis (based on exchange ratios of 0.4098 Phelps Dodge common shares for
each Asarco common share and 0.3135 Phelps Dodge common shares for each Cyprus
Amax common share) were as follows:

<TABLE>
<S>                                                           <C>
Asarco......................................................  $24.00
Cyprus Amax.................................................  $18.36
</TABLE>

                                       50
<PAGE>   58

                            PHELPS DODGE CORPORATION
                       SELECTED HISTORICAL FINANCIAL DATA

     The following is a summary of selected consolidated financial data of
Phelps Dodge for each of the years in the five-year period ended December 31,
1998 and the six-month periods ended June 30, 1999 and 1998. This information is
derived from the selected audited financial data of Phelps Dodge contained in
Phelps Dodge's Annual Report on Form 10-K for the year ended December 31, 1998
and from the unaudited financial statements of Phelps Dodge contained in Phelps
Dodge's Quarterly Report on Form 10-Q for the period ended June 30, 1999, which
are incorporated by reference herein, and from Phelps Dodge's Quarterly Report
on Form 10-Q for the period ended June 30, 1998. See "Where You Can Find More
Information" on page v. You should read this summary together with these
financial statements and their accompanying notes.

<TABLE>
<CAPTION>
                                   AT OR FOR THE
                                    SIX MONTHS
                                  ENDED JUNE 30,                    YEAR ENDED DECEMBER 31,
                                 -----------------     --------------------------------------------------
                                  1999       1998       1998       1997       1996       1995       1994
                                 ------     ------     ------     ------     ------     ------     ------
                                                  (IN MILLIONS EXCEPT PER SHARE AMOUNTS)
<S>                              <C>        <C>        <C>        <C>        <C>        <C>        <C>
  INCOME STATEMENT DATA
  Sales........................  $1,354     $1,593     $3,063     $3,914     $3,787     $4,185     $3,289
  Operating income (loss)......     (27)(a)    348(b)     423(c)     611(d)     713(e)   1,101(f)     400(g)
  Earnings (loss) before
    minority interests.........     (61)       208        199        414        478        760        279
  Minority interests...........      --         (4)        (8)        (5)       (16)       (13)        (8)
  Net earnings (loss)..........     (61)       204        191        409        462        747        271
  Net earnings (loss) per
    Common Share:
    -- Basic...................  $(1.04)    $ 3.49     $ 3.28     $ 6.68     $ 7.02     $10.72     $ 3.84
    -- Diluted.................  $(1.04)    $ 3.48     $ 3.26     $ 6.63     $ 6.98     $10.66     $ 3.82
  Cash dividend per Common
    Share......................  $ 1.00     $ 1.00     $ 2.00     $ 2.00     $ 1.95     $ 1.80     $ 1.69
  BALANCE SHEET DATA
  Cash and marketable
    securities.................  $  144     $  336     $  222     $  158     $  470     $  609     $  287
  Working capital..............     196        516        329        350        736        950        558
  Total assets.................   4,902      5,061      5,037      4,965      4,816      4,646      4,134
  Stockholder's Equity.........   2,373      2,621      2,587      2,510      2,756      2,678      2,188
  OTHER FINANCIAL DATA
  Book value per common
    share......................  $40.91     $44.66     $44.68     $42.81     $42.59     $39.04     $30.95
  Debt as a % of
    capitalization(h)..........   30.5%      26.6%      27.6%      27.7%      18.8%      20.2%      23.6%
  Cash provided from operating
    activities.................  $   46     $  109     $  378     $  765     $  838     $  959     $  543
</TABLE>

- ---------------
(a) Includes non-recurring restructuring charges of $83.0.

(b) Includes before-tax gain of $186.1 from the disposition of a 90 percent
    interest in Accuride Corporation.

(c) Includes before-tax gain of $198.7 from the disposition of the 100 percent
    interest in Accuride Corporation and a non-recurring, before-tax provision
    of $7.8 for curtailments and indefinite closures primarily at Phelps Dodge
    Mining Company.

(d) Includes $45.9 charge primarily for additional provisions of $23.0 for
    estimated future costs associated with environmental matters and $19.1 for a
    voluntary early retirement program.

(e) Includes reclamation reserves of $10.0 for the court-ordered rescission of a
    1986 sale of property in Maspeth, New York, by the Corporation to the United
    States Postal Service.

(f) Includes before-tax gain of $26.8 from the disposition of a Phelps Dodge
    Industries' operating facility.

(g) Includes $98.7 charge for environmental costs and a before-tax loss of $59.0
    for the disposition of certain operating facilities and mining properties.

(h) Total capitalization includes Debt, Minority Interest and Stockholders'
    Equity.

                                       51
<PAGE>   59

                              ASARCO INCORPORATED
                       SELECTED HISTORICAL FINANCIAL DATA

     The following is a summary of selected consolidated financial data of
Asarco for each of the years in the five-year period ended December 31, 1998 and
the six-month periods ended June 30, 1999 and 1998. This information is derived
from the Form S-4 Registration Statement filed by Asarco Cyprus Incorporated in
connection with the proposed Asarco-Cyprus Amax merger. This information is only
a summary and should be read together with the financial statements and
accompanying notes contained in Asarco's Annual Report on Form 10-K for the year
ended December 31, 1998, Asarco's Quarterly Report on Form 10-Q for the period
ended June 30, 1999 and Asarco's Quarterly Report on Form 10-Q for the period
ended June 30, 1998. See "Where You Can Find More Information" on page v.

<TABLE>
<CAPTION>
                                       AT OR FOR THE
                                         SIX MONTHS
                                       ENDED JUNE 30,                 YEAR ENDED DECEMBER 31,
                                      ----------------    -----------------------------------------------
                                       1999      1998      1998      1997      1996     1995(F)     1994
                                      ------    ------    ------    ------    ------    -------    ------
                                                    (IN MILLIONS EXCEPT PER SHARE AMOUNTS)
<S>                                   <C>       <C>       <C>       <C>       <C>       <C>        <C>
INCOME STATEMENT DATA
Sales...............................  $  966    $1,186    $2,233    $2,721    $2,717    $3,198     $2,032
Operating income (loss).............     (49)      (33)     (118)(a)    275(b)    303(d)    487(g)     18(h)
Earnings (loss) before minority
  interests.........................     (52)      (31)     (104)      234       226       299         65
Minority interests..................      (4)      (15)      (27)      (91)      (88)     (130)        (1)
Net earnings (loss).................     (56)      (46)     (131)      143(c)    138(e)    169         64(i)
Earnings (loss) per Common Share:
  Net earnings (loss) --
  Basic.............................  $(1.42)   $(1.17)   $(3.29)   $ 3.42    $ 3.24    $ 4.00     $ 1.53
  Net earnings (loss) --
  Diluted...........................  $(1.42)   $(1.17)   $(3.29)   $ 3.42    $ 3.23    $ 3.98     $ 1.52
Cash Dividend per Common Share......  $ 0.10    $ 0.40    $ 0.70    $ 0.80    $ 0.80    $ 0.70     $ 0.40
BALANCE SHEET DATA
Cash and marketable securities......  $  156    $  285    $  216    $  416    $  193    $  281     $   18
Working capital.....................     335       502       502       726       511       565        282
Total assets........................   3,977     4,020     4,024     4,110     4,120     4,327      3,291
Inventories -- replacement cost in
  excess of LIFO inventory costs....      80        78        74        86       115       137        143
Stockholders' Equity................   1,459     1,623     1,525     1,694     1,737     1,707      1,517
OTHER FINANCIAL DATA
Book value per common share.........  $36.68    $40.92    $38.45    $42.71    $40.56    $40.11     $36.04
Debt as a % of capitalization(j)....   34.8%     30.0%     33.7%     28.3%     26.7%     34.1%      38.1%
Debt as a % of capitalization, net
  of excess cash(j).................   32.4%     24.3%     30.0%     20.2%     24.1%     32.1%      38.1%
Cash provided from (used for)
  operating activities..............  $   74    $   65    $   62    $  321    $  267    $  489     $  (10)
</TABLE>

- ------------
(a) Includes charges of $20.0 to reflect the effect of the sale of Asarco's
    Missouri Lead Division and $10.0 related to Southern Peru Copper
    Corporation's $30.0 cost reduction program. Includes charges of $9.5 for the
    three year suspension of operations at Asarco's copper smelter in El Paso,
    Texas, $9.8 to write down the book value and provide for the closure costs
    of Asarco's Black Cloud lead-zinc mine in Leadville, Colorado, $10.9 for the
    transfer of Southern Peru Copper Corporation's ownership of the Ilo townsite
    to its worker occupants and the city of Ilo, Peru and $7.7 to increase
    reserves for certain employee benefit plans and for severance and other
    costs related to Asarco's cost reduction program. Includes a charge of $33.2
    ($54 in charges offset by $20.8 in anticipated insurance and other
    recoveries) to increase reserves for closed plants and environmental
    matters.

(b) Environmental charges of $22.1 in 1997, include charges of $30.0 offset
    entirely by anticipated insurance recoveries.

(c) Includes a $47.6 after-tax gain ($73.3 pre-tax) from the sale of shares of
    Grupo Mexico, S.A. de C.V.

                                              (footnotes continued on next page)
                                       52
<PAGE>   60

(d) Includes a $15.0 charge ($67.7 in charges offset by $52.7 in insurance
    settlements and other recoveries) for closed plant and environmental
    matters.

(e) Includes a $39.0 after-tax gain ($60.1 pre-tax) from the sale of Asarco's
    remaining interest in MIM and a $7.2 after-tax gain ($11.1 pre-tax) from the
    sale of a 25% interest in Asarco's Silver Bell project.

(f) On April 5, 1995, ASARCO acquired an additional 10.7% interest in Southern
    Peru Copper Corporation for $116.4 increasing its ownership from 52.3% to
    63%. The additional shares acquired enabled Asarco to elect a majority of
    the directors of Southern Peru Copper Corporation. As a result, Asarco has
    consolidated Southern Peru Copper Corporation in its financial statements
    based on its 52.3% ownership, effective January 1, 1995, and 63% ownership,
    effective April 5, 1995. Asarco previously accounted for its investment in
    Southern Peru Copper Corporation by the equity method. As of June 30, 1999,
    Asarco's ownership interest in Southern Peru Copper Corporation was 54.3%.

(g) Includes a $139.4 charge to add to Asarco's reserve for closed plant and
    environmental matters, to provide for asset impairments and plant closures
    and to write down certain in-process inventory to net realizable value.

(h) Includes a $65.5 pre-tax charge to add to Asarco's reserve for closed plant
    and environmental matters.

(i) Includes a $31.9 after-tax gain ($58.5 pre-tax) from the sale of Asarco's
    remaining interest in Asarco Australia Limited.

(j) Total capitalization includes Debt, Minority Interest and Stockholders'
    Equity.

                                       53
<PAGE>   61

                          CYPRUS AMAX MINERALS COMPANY
                       SELECTED HISTORICAL FINANCIAL DATA

     The following is a summary of selected consolidated financial data of
Cyprus Amax for each of the years in the five-year period ended December 31,
1998 and the six-month periods ended June 30, 1999 and 1998. This information is
derived from the Form S-4 Registration Statement filed by Asarco Cyprus
Incorporated in connection with the proposed Asarco-Cyprus Amax merger. This
information is only a summary and should be read together with the financial
statements and accompanying notes contained in Cyprus Amax's Annual Report on
Form 10-K for the year ended December 31, 1998, Cyprus Amax's Quarterly Report
on Form 10-Q for the period ended June 30, 1999 and Cyprus Amax's Quarterly
Report on Form 10-Q for the period ended June 30, 1998. See "Where You Can Find
More Information" on page v.

<TABLE>
<CAPTION>
                                        AT OR FOR THE
                                          SIX MONTHS
                                        ENDED JUNE 30,                YEAR ENDED DECEMBER 31,
                                       ----------------    ----------------------------------------------
                                        1999      1998      1998      1997      1996      1995      1994
                                       ------    ------    ------    ------    ------    ------    ------
                                                     (IN MILLIONS EXCEPT PER SHARE AMOUNTS)
<S>                                    <C>       <C>       <C>       <C>       <C>       <C>       <C>
INCOME STATEMENT DATA(a)
Revenue..............................  $  561    $  870    $1,661    $1,978    $1,584    $1,908    $1,540
Operating income (loss)..............     (13)       18        52       249        63       485       202
Income (loss) from Continuing
  Operations(b)......................     (77)      (53)     (134)       89        15       367       104
Net Income (loss)(c).................     (74)      (32)      (75)       69        77       124       175
Earnings (loss) per Common Share:
  Income (loss) from Continuing
    Operations(b)....................  $(0.95)   $(0.67)   $(1.65)   $ 0.76    $(0.04)   $ 3.75    $ 0.92
  Net earnings (loss)(c).............  $(0.92)   $(0.44)   $(1.02)   $  .54    $ 0.62    $ 1.13    $ 1.69
Cash Dividend per Common Share.......  $ 0.25    $ 0.40    $ 0.80    $ 0.80    $ 0.80    $ 0.80    $ 0.90
BALANCE SHEET DATA
Cash and Cash Equivalents............  $1,275    $  180    $  353    $  250    $  193    $  191    $  139
Working capital......................     970       232       250       297       304       292       423
Total assets.........................   4,746     5,441     5,341     6,459     6,786     6,196     5,407
Long-Term Debt and Capital Lease
  Obligations........................   1,525     1,791     1,718     2,202     2,554     1,877     1,391
Stockholders' Equity.................   2,059     2,264     2,157     2,330     2,360     2,365     2,329
OTHER FINANCIAL DATA
Book Value Per Common Share..........  $20.17    $22.21    $21.32    $22.99    $23.43    $23.62    $23.39
Long-Term Debt/Total
  Capitalization(d)..................   42.3%     43.8%     43.9%     46.9%     50.4%     42.6%     37.4%
Net Long-Term Debt/Total
  Capitalization(d)(e)...............   10.7%     41.2%     38.4%     44.0%     48.4%     40.0%     34.9%
Cash Provided by Operating
  Activities.........................  $   47    $  129    $  237    $  481    $  440    $  675    $  110
</TABLE>

- ---------------
(a) The Cyprus Amax historical consolidated income statement data has been
    restated to reflect the Domestic Coal Division as a Discontinued Operation
    due to its sale effective June 30, 1999.

(b) Income (loss) from Continuing Operations reflects net after-tax copper
    charges of $94 for environmental remediation liabilities and write-downs,
    net after-tax gains of $123 from the sale of the lithium business, an
    Oakbridge coal mine in Australia, and real estate, a net after-tax charge of
    $22 for legal settlements, a net after-tax charge of $37 for Cyprus Amax's
    share of the Kinross asset impairment and the sale by Kinross of the
    pre-merger Amax Gold hedging portfolio, and an after-tax charge of $4 for
    various special items in 1998; an after-tax charge of $13 for the write-
    down of Oakbridge's Clarence mine in Australia, favorable tax adjustments of
    $38, an after-tax gain of $19 on the sale of Kubaka to Amax Gold, and an
    after-tax charge of $5 for the costs of redeeming the 9 7/8% Notes in 1997;
    an after-tax charge of $74 for environmental remediation liabilities, costs
    to temporarily close a copper mine, the write-down of the net assets of the
    Guanaco gold mine, and an unrelated favorable tax adjustment for Amax Gold
    in 1996; an after-tax charge of $4 to write-down assets of an Oakbridge mine
    in Australia in 1995; and an after-tax gain of $21 for various special items
    in 1994.

(c) Discontinued Operations for the six months ended June 30, 1999 included
    earnings from the domestic coal business of $16 after-tax and a $13
    after-tax loss on the sale of the coal assets. In addition, for the six
    months ended June 30, 1998 and for the years 1994 through 1998, the results
    have been restated to reflect the Domestic Coal Division as a discontinued
    operation. Discontinued

                                              (footnotes continued on next page)
                                       54
<PAGE>   62

    Operations included for the six months ended 1998 after-tax earnings of $21;
    after-tax earnings of $59 that reflects a loss on the sale of certain
    eastern and midwestern coal properties of $12 and favorable legal
    settlements of $5 for 1998; after-tax loss of $20 that reflects charges of
    $66 for write-downs for 1997; after-tax earnings of $62 for 1996; after-tax
    loss of $243 that reflects a charge of $334 for the write-down of certain
    coal assets and provisions for associated liabilities for 1995; and
    after-tax earnings of $62 that reflects a write-down of $8 for the Orchard
    Valley mine for 1994. Also in 1994 Discontinued Operations included income
    from the Oil and Gas business for the first quarter of 1994 of $7 after-tax
    and a $2 after-tax gain on the sale of Cyprus Amax-owned oil and gas assets.

(d) Total Capitalization includes Debt, Minority Interest and Stockholders'
    Equity.

(e) Net Long-Term Debt includes Long-term debt less Cash and Cash Equivalents.

                                       55
<PAGE>   63

                                  PHELPS DODGE

                       COMPARATIVE PER SHARE INFORMATION

     The following table presents historical per common share information for
Phelps Dodge and Cyprus Amax, and the pro forma and equivalent pro forma per
common share data giving effect to the combination of Phelps Dodge and Cyprus
Amax and Phelps Dodge, Cyprus Amax and Asarco, for the six months ended June 30,
1999 and the year ended December 31, 1998. The pro forma combined per share
information does not purport to represent what the combined financial position
or results of operations would actually have been if the combinations had
occurred at January 1, 1998, nor are they necessarily indicative of Phelps
Dodge's future consolidated results of operations or financial position. The
information tabled below should be read in conjunction with the historical
financial statements of the combining corporations and the "Selected Historical
Financial Data" of Phelps Dodge, Asarco and Cyprus Amax on pages 51 through 55,
and the "Unaudited Pro Forma Combined Financial Information" on page 58.

<TABLE>
<CAPTION>
                                                            SIX MONTHS
                                                               ENDED           YEAR ENDED
                                                           JUNE 30, 1999    DECEMBER 31, 1998
                                                           -------------    -----------------
<S>                                                        <C>              <C>
Per common share
  Historical:
     Phelps Dodge
       Book value(1).....................................     $40.91             $44.68
       Net income(loss)
          Basic..........................................      (0.98)              3.28
          Diluted........................................      (0.98)              3.26
       Cash dividends....................................       1.00               2.00
     Cyprus Amax
       Book value(1).....................................      20.17              21.32
       Net income(loss)
          Basic..........................................      (0.95)             (1.65)
          Diluted........................................      (0.95)             (1.65)
       Cash dividends....................................       0.25               0.80
  Pro forma:
     Combined Phelps Dodge and Cyprus Amax
       Book value(1).....................................      46.74              50.45
       Income(loss) from continuing operations--Basic and
          Diluted........................................      (1.62)              0.24
       Cash dividends(2).................................       1.00               2.00
     Cyprus Amax Equivalent(3)
       Book value(1).....................................      14.65              15.82
       Income(loss) from continuing operations--Basic and
          Diluted........................................      (0.51)              0.08
       Cash dividends....................................       0.31               0.63
     Combined Phelps Dodge, Asarco and Cyprus Amax
       Book value(1).....................................      49.95              53.72
       Income(loss) from continuing operations--Basic and
          Diluted........................................      (1.67)             (0.57)
       Cash dividends(2).................................       1.00               2.00
</TABLE>

                                                        (footnotes on next page)
                                       56
<PAGE>   64

<TABLE>
<CAPTION>
                                                            SIX MONTHS
                                                               ENDED           YEAR ENDED
                                                           JUNE 30, 1999    DECEMBER 31, 1998
                                                           -------------    -----------------
<S>                                                        <C>              <C>
     Asarco Equivalent(3)
       Book value(1).....................................      20.47              22.01
       Income(loss) from continuing operations--Basic and
          Diluted........................................      (0.68)             (0.23)
       Cash dividends....................................       0.41               0.82
     Cyprus Amax Equivalent(3)
       Book value(1).....................................      15.66              16.84
       Income(loss) from continuing operations--Basic and
          Diluted........................................      (0.52)             (0.18)
       Cash dividends....................................       0.31               0.63
</TABLE>

- ---------------
(1) Book value per share is determined as at June 30, 1999 and December 31,
    1998.

(2) Pro forma combined cash dividends per share of Phelps Dodge common stock
    reflect Phelps Dodge's historical dividend rate per share declared in the
    periods presented.

(3) Pro forma combined equivalent per share of Asarco and Cyprus Amax common
    stocks reflects the pro forma combined per share of Phelps Dodge's common
    stock amount multiplied by the exchange ratio of 0.4098 and 0.3135 of Phelps
    Dodge stock for each share of Asarco and Cyprus Amax respectively.

                                       57
<PAGE>   65

               UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION

     The Unaudited Pro Forma Combined Financial Information of Phelps Dodge
Corporation (Phelps Dodge) presented following is derived from the historical
consolidated financial statements of Phelps Dodge, ASARCO Incorporated (Asarco)
and Cyprus Amax Minerals Company (Cyprus Amax). The Unaudited Pro Forma Combined
Financial Information is presented under two separate scenarios (collectively
the "Transactions"): (i) the acquisition by Phelps Dodge of Cyprus Amax; and
(ii) the acquisition by Phelps Dodge of Asarco and Cyprus Amax. The acquisitions
of Asarco and Cyprus Amax are not dependent upon each other. Under each of the
scenarios, the Unaudited Pro Forma Combined Financial Information is prepared
using the purchase method of accounting, with Phelps Dodge treated as the
acquirer and as if the transactions had been completed as of January 1, 1998,
for statement of operations purposes and on June 30, 1999, for balance sheet
purposes.

     For a summary of the proposed business combinations, see "The Offer"
beginning on page 32 of this prospectus.

     The Unaudited Pro Forma Combined Financial Information is based upon the
historical financial statements of Phelps Dodge, Asarco and Cyprus Amax adjusted
to give effect to the proposed business combinations. The pro forma assumptions
and adjustments for each transaction scenario are described in the accompanying
notes presented on the following pages. The assumptions and related pro forma
adjustments have been developed from information available to Phelps Dodge from
the December 31, 1998, Form 10-K filings and June 30, 1999, Form 10-Q filings of
Asarco and Cyprus Amax and the Form 8-K filing dated June 30, 1999, of Cyprus
Amax. Such pro forma adjustments have been included only to the extent known and
reasonably available to Phelps Dodge.

     Phelps Dodge also has reviewed the Form S-4 Registration Statement of
Asarco Cyprus Incorporated filed on August 20, 1999, in connection with the
proposed merger of Asarco and Cyprus Amax. Their filing included unaudited pro
forma combined financial information for Asarco and Cyprus Amax as if the merger
had occurred at specific assumed dates. Certain pro forma adjustments that
Phelps Dodge noted in reviewing this unaudited pro forma combined financial
information have not been incorporated in the accompanying Unaudited Pro Forma
Combined Financial Information because information necessary to make or assess
such adjustments is not available to Phelps Dodge.

     As a consequence of the nature of the Transactions, there may be, and
likely will be, actions and other events or changes initiated by Asarco and/or
Cyprus Amax that would significantly change purchase prices and purchase price
allocations. Also, Phelps Dodge has not had access to additional proprietary and
confidential corporate financial and other information of Asarco and Cyprus Amax
and has not had an opportunity to undertake any due diligence procedures. Such
information and procedures may provide Phelps Dodge with additional information
that could materially affect the purchase price paid for the acquisition of
Asarco or Cyprus Amax, the purchase price allocation and, accordingly, the
assumptions and pro forma adjustments. Identified factors which may have a
significant impact on the basis and results of the combinations are described in
Note 2 of the accompanying notes to the Unaudited Pro Forma Combined Balance
Sheet and Combined Statements of Operations for each scenario.

     Furthermore, the ultimate determination of the purchase price paid for the
acquisition of Cyprus Amax and Asarco may change significantly from the current
estimate. For the purpose of this Unaudited Pro Forma Combined Financial
Information, the purchase price has been estimated based upon the market price
of $58.6875 for each Phelps Dodge common share, that being the last quoted price
at the moment Asarco and Cyprus Amax trading was halted on August 20, 1999. The
final purchase price will be based largely upon the average market price of
Phelps Dodge common stock at the earlier of the dates the combinations are
announced or consummated between Phelps Dodge, Asarco and Cyprus Amax. As a
result of these uncertainties, the final determination and allocation of
purchase price may differ from the amounts assumed in this Unaudited Pro Forma
Combined Financial Information and those differences may be material.

     The Unaudited Pro Forma Combined Financial Information is provided for
illustrative purposes only and does not purport to represent what the actual
consolidated results of operations or the consolidated financial

                                       58
<PAGE>   66

positions of Phelps Dodge would have been had the acquisitions of Asarco and/or
Cyprus Amax occurred on the respective dates assumed, nor is it necessarily
indicative of future consolidated operating results or financial position.

     The Unaudited Pro Forma Combined Financial Information does not include the
realization of cost savings from operating efficiencies, synergies or other
restructurings resulting from the Transactions and does not contemplate the
liabilities that may be incurred in any related restructurings. Phelps Dodge
estimated consolidated annual cash cost savings of at least $200 million as a
result of synergies, reduced overhead costs and other actions resulting from the
combination of all three companies. Phelps Dodge believes that the Transactions
and the resulting activities would yield substantial cash cost savings of at
least $75 million beyond those that can be realized by Asarco Cyprus
Incorporated which were estimated to be $125 million in the Form S-4
Registration Statement of Asarco Cyprus Incorporated filed on August 20, 1999.
There is no assurance that these cost savings can or will be realized.

     This Unaudited Pro Forma Combined Financial Information should be read in
conjunction with the separate historical consolidated financial statements and
accompanying notes of Phelps Dodge, Asarco and Cyprus Amax that are incorporated
by reference in this Registration Statement. You should not rely on the
Unaudited Pro Forma Combined Financial Information as an indication of the
consolidated results of operations or financial position that would have been
achieved if the business combinations had taken place earlier or of the
consolidated results of operations or financial position of Phelps Dodge after
the completion of such transactions.

                                       59
<PAGE>   67

                            PHELPS DODGE CORPORATION

                   PRO FORMA COMBINED STATEMENT OF OPERATIONS
                 PHELPS DODGE, ASARCO AND CYPRUS AMAX COMBINED
                     FOR THE SIX MONTHS ENDED JUNE 30, 1999
                                  (UNAUDITED)
              (AMOUNTS IN MILLIONS, EXCEPT PER SHARE INFORMATION)

<TABLE>
<CAPTION>
                                               HISTORICAL
                                   -----------------------------------    PRO FORMA      PRO FORMA
                                   PHELPS DODGE   ASARCO   CYPRUS AMAX   ADJUSTMENTS     COMBINED
                                   ------------   ------   -----------   -----------     ---------
<S>                                <C>            <C>      <C>           <C>             <C>
Sales and other operating
  revenues.......................     $1,354        966        561             --          2,881
                                      ------      -----        ---         ------          -----
Operating costs and expenses
  Cost of products sold..........      1,073        855        428             --          2,356
  Depreciation, depletion and
     amortization................        144         73        104            (41)(H)        280
  Selling and general
     administrative expense......         60         72         34             --            166
  Exploration and research
     expense.....................         21         11          8             --             40
  Non-recurring charges and
     provision for asset
     dispositions*...............         83          4         --             --             87
                                      ------      -----        ---         ------          -----
                                       1,381      1,015        574            (41)         2,929
                                      ------      -----        ---         ------          -----
Operating income (loss)..........        (27)       (49)       (13)            41            (48)
  Interest expense...............        (48)       (38)       (69)            (9)(D)
                                                                               (4)(A)
                                                                               (3)(J)       (171)
  Capitalized interest...........         --         --          2              4(A)           6
  Miscellaneous income and
     expense, net................         (7)        10        (11)            (1)(I)
                                                                                6(A)          (3)
                                      ------      -----        ---         ------          -----
Income (loss) before taxes,
  minority interests and equity
  in net earnings of affiliated
  companies......................        (82)       (77)       (91)            34           (216)
  Provision for taxes on
     income......................         19         25         14             (1)(A)
                                                                              (10)(E)         47
  Minority interests in
     consolidated subsidiaries...          1         (4)        --              1(I)          (2)
  Equity in net earnings (losses)
     of affiliated companies.....          5         --         --             (5)(A)         --
                                      ------      -----        ---         ------          -----
Income (loss) from continuing
  operations.....................        (57)       (56)       (77)            19           (171)
  Preferred stock dividends......         --         --         (9)             9(D)          --
                                      ------      -----        ---         ------          -----
Income (loss) from continuing
  operations applicable to common
  shares.........................     $  (57)       (56)       (86)            28           (171)
                                      ======      =====        ===         ======          =====
Net earnings (loss) per share
  Basic..........................     $(0.98)                                              (1.67)
  Diluted........................     $(0.98)                                              (1.67)
Weighted average shares
  outstanding
  Basic..........................       57.8                                               102.5
  Diluted........................       57.8                                               102.5
</TABLE>

- ------------
* See historical financial statements incorporated by reference in this
  prospectus for a description of non-recurring charges and provision for asset
  dispositions.

                                       60
<PAGE>   68

                            PHELPS DODGE CORPORATION

                   PRO FORMA COMBINED STATEMENT OF OPERATIONS
                 PHELPS DODGE, ASARCO AND CYPRUS AMAX COMBINED
                          YEAR ENDED DECEMBER 31, 1998
                                  (UNAUDITED)
              (AMOUNTS IN MILLIONS, EXCEPT PER SHARE INFORMATION)

<TABLE>
<CAPTION>
                                                 HISTORICAL
                                     -----------------------------------    PRO FORMA     PRO FORMA
                                     PHELPS DODGE   ASARCO   CYPRUS AMAX   ADJUSTMENTS    COMBINED
                                     ------------   ------   -----------   -----------    ---------
<S>                                  <C>            <C>      <C>           <C>            <C>
Sales and other operating
  revenues.........................     $3,064      2,233       1,660           (218)(A)    6,739
                                        ------      -----       -----        -------       ------
Operating costs and expenses
  Cost of products sold............      2,361      1,963       1,087           (200)(A)    5,211
  Depreciation, depletion and
    amortization...................        293        145         254             (7)(A)
                                                                                 (80)(H)      605
  Selling and general
    administrative expense.........        123        144         105             --          372
  Exploration and research
    expense........................         55         27          45             --          127
  Non-recurring charges and
    provision for asset
    dispositions*..................       (191)        72         118             --           (1)
                                        ------      -----       -----        -------       ------
                                         2,641      2,351       1,609           (287)       6,314
                                        ------      -----       -----        -------       ------
Operating income (loss)............        423       (118)         51             69          425
  Interest expense.................        (97)       (68)       (157)           (19)(D)
                                                                                 (13)(A)
                                                                                  (5)(J)     (359)
  Capitalized interest.............          2         --           2             13(A)        17
  Miscellaneous income and expense,
    net............................          9         29          17             (6)(I)
                                                                                  (4)(A)       45
                                        ------      -----       -----        -------       ------
Income (loss) before taxes,
  minority interests and equity in
  net earnings of affiliated
  companies........................        337       (157)        (87)            35          128
  Provision for taxes on income....       (134)        53         (11)           (16)(E)     (108)
  Minority interests in
    consolidated subsidiaries......         (8)       (27)          1              8(I)       (26)
  Equity in net earnings (losses)
    of affiliated companies........         (4)        --         (53)             4(A)       (53)
                                        ------      -----       -----        -------       ------
Income (loss) from continuing
  operations.......................        191       (131)       (150)            31          (59)
  Preferred stock dividends........         --         --         (19)            19(D)        --
                                        ------      -----       -----        -------       ------
Income (loss) from continuing
  operations applicable to common
  shares...........................     $  191       (131)       (169)            50       $  (59)
                                        ======      =====       =====        =======       ======
Net earnings (loss) per share
  Basic............................     $ 3.28                                              (0.57)
  Diluted..........................     $ 3.26                                              (0.57)
Weighted average shares outstanding
  Basic............................       58.2                                              102.9
  Diluted..........................       58.5                                              102.9
</TABLE>

- ------------
*  See historical financial statements incorporated by reference in this
   prospectus for a description of non-recurring charges and provision for asset
   dispositions.

                                       61
<PAGE>   69

                            PHELPS DODGE CORPORATION

                        PRO FORMA COMBINED BALANCE SHEET
                 PHELPS DODGE, ASARCO AND CYPRUS AMAX COMBINED
                                 JUNE 30, 1999
                                  (UNAUDITED)
                             (AMOUNTS IN MILLIONS)

<TABLE>
<CAPTION>
                                                HISTORICAL
                                    -----------------------------------    PRO FORMA     PRO FORMA
                                    PHELPS DODGE   ASARCO   CYPRUS AMAX   ADJUSTMENTS    COMBINED
                                    ------------   ------   -----------   -----------    ---------
<S>                                 <C>            <C>      <C>           <C>            <C>
ASSETS
  Cash and cash equivalents.......     $  144        125       1,275           (30)(B)
                                                                                (5)(D)     1,509
  Accounts receivable, net........        396        404          37            --           837
  Inventories.....................        263        305         239          (127)(A)
                                                                                84(C)        764
  Supplies........................        104         --          55           127(A)        286
  Prepaid expenses and other
    assets........................         15        135          74             5(C)
                                                                               (33)(A)       196
  Deferred income taxes...........         45         --          32            33(A)        110
                                       ------      -----       -----        ------        ------
    Current assets................        967        969       1,712            54         3,702
  Investments and long-term
    accounts receivable...........         95        190         328            29(C)
                                                                               (13)(I)
                                                                                 9(A)        638
  Property, plant and equipment,
    net...........................      3,501      2,592       2,546        (1,037)(C)     7,602
  Other assets and deferred
    charges.......................        339        226         160            (9)(A)
                                                                                 5(D)        721
                                       ------      -----       -----        ------        ------
         Total Assets.............     $4,902      3,977       4,746          (962)       12,663
                                       ======      =====       =====        ======        ======
LIABILITIES
  Short-term debt.................     $  214         16         249            --           479
  Current portion of long-term
    debt..........................         62         31          79            --           172
  Accounts payable and accrued
    expenses......................        456        496         324            --         1,276
  Dividends payable...............         29         --           9            --            38
  Accrued income taxes............         11         90          81            --           182
                                       ------      -----       -----        ------        ------
    Current liabilities...........        772        633         742            --         2,147
  Long-term debt..................        801      1,017       1,499           244(D)
                                                                               (95)(C)     3,466
  Deferred income taxes...........        493         28          14          (253)(E)       282
  Other liabilities and deferred
    credits.......................        376        306         412            52(C)      1,146
                                       ------      -----       -----        ------        ------
                                        2,442      1,984       2,667           (52)        7,041
                                       ------      -----       -----        ------        ------
Minority interests in consolidated
  subsidiaries....................         86        534          20          (147)(I)       493
                                       ------      -----       -----        ------        ------
Common shareholders' equity
  Common shares...................        362        525           1          (526)(G)
                                                                               279(F)        641
  Treasury shares.................         --         --         (86)           86(A)         --
  Preferred shares................         --         --           5            (5)(D)        --
  Capital in excess of par
    value.........................          5         --       2,912           (86)(A)
                                                                            (2,826)(G)
                                                                             2,342(F)      2,347
  Retained earnings...............      2,198        949        (768)          134(I)
                                                                              (181)(G)     2,332
  Accumulated other comprehensive
    income (loss).................       (183)       (15)         (5)           20(G)       (183)
  Other...........................         (8)        --          --            --            (8)
                                       ------      -----       -----        ------        ------
         Total Shareholders'
           Equity.................      2,374      1,459       2,059          (763)        5,129
                                       ------      -----       -----        ------        ------
         Total Liabilities and
           Shareholders' Equity...     $4,902      3,977       4,746          (962)       12,663
                                       ======      =====       =====        ======        ======
</TABLE>

                                       62
<PAGE>   70

              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                         COMBINED FINANCIAL INFORMATION

1.  BASIS OF PRESENTATION

     The Unaudited Pro Forma Combined Financial Information has been derived
from historical consolidated financial statements of Phelps Dodge, Asarco and
Cyprus Amax incorporated by reference into this prospectus. See Phelps Dodge
"Unaudited Pro Forma Combined Financial Information" on page 58 of this
prospectus.

     The assumptions and related pro forma adjustments described below have been
developed from public historical information available to Phelps Dodge. Pro
forma adjustments have been included only to the extent known and reasonably
available to Phelps Dodge. Additional information may exist that could
materially affect the assumptions and related pro forma adjustments. Such
information is not available to Phelps Dodge because it is within the particular
and singular knowledge of Asarco and Cyprus Amax.

2.  THE OFFER

     Phelps Dodge is proposing a three-way business combination of Phelps Dodge,
Asarco and Cyprus Amax through separate offerings to exchange all the issued and
outstanding Asarco and Cyprus Amax common shares for Phelps Dodge common shares.
See "The Offer" on page 32 of this prospectus.

     Phelps Dodge proposes to exchange all the issued and outstanding Asarco and
Cyprus Amax common shares for Phelps Dodge common shares at an exchange ratio of
0.4098 Phelps Dodge common share for each Asarco common share and an exchange
ratio of 0.3135 Phelps Dodge common share for each Cyprus Amax common share.

     The transactions would be accounted for under the purchase method. The
purchase price for the business combinations is estimated as follows (dollars in
millions and shares in thousands except per share data):

<TABLE>
<CAPTION>
                                                           ASARCO    CYPRUS AMAX    COMBINED
                                                           ------    -----------    --------
<S>                                                        <C>       <C>            <C>
Common shares outstanding (as reported in June 30, 1999,
  Form 10-Qs)............................................  39,783      90,454
Exchange offer ratio of Phelps Dodge common shares for
  each common share......................................  0.4098      0.3135
Phelps Dodge common shares to be issued..................  16,303      28,357         44,660
Market price of each Phelps Dodge common share on August
  20, 1999, prior to trading halt........................                           $58.6875
                                                                                    ========
Fair value of Phelps Dodge common shares issued,
  comprising par value of $279 ($6.25 per share) and
  capital in excess of par of $2,342.....................                           $  2,621
Redemption of Cyprus Amax Series A Preferred Stock (Note
  3D)....................................................                                244
Estimated transaction costs..............................                                 30
                                                                                    --------
Purchase price...........................................                           $  2,895
                                                                                    ========
</TABLE>

     The final purchase price could change materially from the purchase price
estimated above as a result of changes in the market price of common shares of
Phelps Dodge and/or the relative market price of Asarco and Cyprus Amax common
shares. There are arrangements in place at Asarco and Cyprus Amax that could
impact the purchase price including employment agreements, change of control
agreements, severance agreements, restricted stock awards, stock appreciation
rights, and certain pension and other employee benefit plans. In addition,
actions may be taken by the management of Asarco and Cyprus Amax, in a defensive
posture or for other reasons, that could impact the purchase price including
amending existing agreements or

                                       63
<PAGE>   71
              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                 COMBINED FINANCIAL INFORMATION -- (CONTINUED)

issuing stock options and other similar bonus awards. The potential impact of
these factors cannot be estimated but could be material.

     The estimated purchase price does not give effect to outstanding stock
options which could impact the number of Phelps Dodge shares issued and/or the
purchase price either by their exercise or their conversion to outstanding stock
options of Phelps Dodge. Such effects prior to completion of the business
combination cannot be reasonably estimated from available public information. As
reported in their December 31, 1998, Form 10-Ks, Asarco and Cyprus Amax had
1,721,249 and 6,346,801 stock options outstanding, respectively. Cyprus Amax had
2,024,009 outstanding stock options with weighted average exercise prices less
than the per share equivalent value of Cyprus Amax common stock as determined by
the terms of the exchange offer. Asarco's stock options had an average exercise
price of $26.12, more than the per share equivalent value of Asarco's common
stock as determined by the exchange offer. If Cyprus Amax's 2,024,009 stock
options and all of Asarco's outstanding stock options were exercised prior to
consummation of the business combinations, the estimated purchase price would be
increased by approximately $78 million which would be substantially offset by
cash and cash equivalents received as proceeds from such exercises. Although it
is Phelps Dodge's desire that all outstanding Asarco and Cyprus Amax stock
options be converted to Phelps Dodge stock options at the respective offering
exchange ratio, it is not assured whether such conversions can be achieved in
whole or in part nor, consequently, the potential effect on the purchase price.

     The estimated purchase price does not include any effect of Cyprus Amax's
outstanding preferred share purchase rights or Asarco's Shareholder Rights Plan.
As described in its December 31, 1998, Form 10-K, Cyprus Amax issued in February
1999 one preferred purchase right for each share of common stock which confers
certain rights to the holder including certain rights in the event of an
acquisition of 15% or more of Cyprus Amax's common stock. As described in
Asarco's December 31, 1998, Form 10-K, Asarco adopted a new Shareholder Rights
Plan in January 1998 that provides certain common stock purchase rights if a
person or group becomes the beneficial owner of 15% or more of Asarco's common
stock, with certain exceptions.

     The final determination of the purchase price may differ from the amount
assumed in the Unaudited Pro Forma Combined Financial Information and that
difference may be material.

3.  PRO FORMA ASSUMPTIONS AND ADJUSTMENTS

     The following assumptions and related pro forma adjustments give effect to
the proposed business combinations of Phelps Dodge, Asarco and Cyprus Amax as if
such combinations occurred on January 1, 1998, in the Unaudited Pro Forma
Combined Statements of Operations for the six-month interim period ended June
30, 1999, and for the year ended December 31, 1998, respectively, and on June
30, 1999, for the Unaudited Pro Forma Combined Balance Sheet.

     The Unaudited Pro Forma Combined Financial Information is provided for
illustrative purposes only and does not purport to represent what the actual
consolidated results of operations or the consolidated financial position of
Phelps Dodge would have been had the business combinations with Asarco and
Cyprus Amax occurred on the respective dates assumed, nor is it necessarily
indicative of future consolidated operating results or financial position.

     Future cash cost savings, which Phelps Dodge estimated will be at least
$200 million annually, are not recognized in this Unaudited Pro Forma Combined
Financial Information. Non-recurring items related to 1998 and the six-month
interim period ended June 30, 1999, are included (see "Selected Historical
Financial Data" at pages 51 through 55 for a summary of non-recurring items and
special charges) and

          (A) Reclassifications have been made to the Asarco and Cyprus Amax
     historical consolidated financial information to conform to Phelps Dodge's
     presentation. The historical financial information of Cyprus Amax excludes
     the results of operations and assets of its discontinued Coal segment as
     reported

                                       64
<PAGE>   72
              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                 COMBINED FINANCIAL INFORMATION -- (CONTINUED)

     for 1998 operations in Cyprus Amax's Form 8-K dated June 30, 1999, and as
     reported as of and for the six months ended June 30, 1999, in its Form 10-Q
     filing for such period. Cyprus Amax's historical financial information for
     the year ended December 31, 1998, also has been adjusted to exclude the
     identifiable results of recurring operations of its Lithium segment which
     was sold in October 1998.

<TABLE>
<CAPTION>
                                    BALANCE SHEET     SIX MONTHS      YEAR ENDED
                                     AT JUNE 30,    ENDED JUNE 30,   DECEMBER 31,
         (IN $ MILLIONS):               1999             1999            1998
- ----------------------------------  -------------   --------------   ------------
<S>                                 <C>             <C>              <C>
Asarco reclassification
  adjustments:
  Inventories.....................      (127)
  Supplies........................       127
  Deferred income taxes (current
     asset).......................        33
  Prepaid expenses and other
     assets.......................       (33)
  Miscellaneous income and
     expense, net.................                        (2)              (4)
  Equity in net earnings of
     affiliated companies.........                         2                4
  Interest expense................                         4               13
  Capitalized interest............                        (4)             (13)
Cyprus Amax reclassification
  adjustments:
  Investments and notes
     receivable...................         9
  Other assets and deferred
     charges......................        (9)
  Treasury shares.................        86
  Capital in excess of par
     value........................       (86)
  Miscellaneous income and
     expense, net.................                         8
  Provision for taxes on income...                        (1)
  Equity in net earnings (losses)
     of affiliated companies......                        (7)
Elimination of recurring results
  from the disposed Cyprus Amax
  Lithium segment:
  Sales and other operating
     revenues.....................                                       (218)
  Cost of products sold
     (derived)....................                                       (200)
  Depreciation, depletion and
     amortization expense.........                                         (7)
</TABLE>

          (B) Phelps Dodge estimates it will incur approximately $30 million of
     transaction costs, consisting primarily of investment bankers, attorneys
     and accountant fees, and financial printing and other charges. These
     estimates are preliminary and therefore are subject to change.

          (C) If the business combinations are consummated, they will be
     accounted for using the purchase method of accounting in accordance with
     generally accepted accounting principles. Accordingly, the assets and
     liabilities of Asarco and Cyprus Amax would be recorded at their estimated
     fair values.

          Phelps Dodge has not had access to information that is within the
     peculiar knowledge of Asarco and Cyprus Amax and has not performed its due
     diligence necessary to determine the fair value of their assets

                                       65
<PAGE>   73
              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                 COMBINED FINANCIAL INFORMATION -- (CONTINUED)

     or liabilities or to identify unknown liabilities or obligations. Pro forma
     adjustments to allocate the purchase price have been recorded in the
     Unaudited Pro Forma Combined Financial Information on the basis of fair
     values reported for certain assets and liabilities in public information of
     Asarco and Cyprus Amax. Because fair value information for the remaining
     assets and liabilities and any possible identifiable intangible assets are
     not reasonably available to Phelps Dodge, the excess of the historical net
     book values of Asarco's and Cyprus Amax's assets acquired over the
     estimated purchase price has been allocated as a reduction of their
     combined net property, plant and equipment.

          Additionally, Phelps Dodge believes that cost savings will be realized
     upon the consolidation and integration of the three companies. Phelps Dodge
     has not developed formal plans for combining the three operations.
     Accordingly, additional liabilities may be incurred in connection with the
     business combinations and any ultimate restructuring. These additional
     liabilities and costs have not been contemplated in the Unaudited Pro Forma
     Combined Financial Information because information necessary to reasonably
     estimate such costs and to formulate detailed restructuring plans is not
     available to Phelps Dodge. Accordingly, the allocation of the purchase
     price cannot be estimated with a reasonable degree of accuracy and may
     differ materially from the amounts assumed in the Unaudited Pro Forma
     Combined Financial Information.

     The pro forma purchase price allocation adjustments are estimated as
follows (in millions):

<TABLE>
<S>                                                           <C>
Reduction of debt to fair value (as reported in Cyprus
  Amax's June 30, 1999, Form 10-Q and the Form S-4
  Registration Statement of Asarco Cyprus Incorporated filed
  August 20, 1999)..........................................  $   95
Restricted investment in Grupo Mexico (as reported in
  Asarco's December 31, 1998, Form 10-K)....................  $   29
Increase in LIFO based inventory to replacement cost (as
  reported in Asarco's June 30, 1999, Form 10-Q and in
  Cyprus Amax's December 31, 1998, Form 10-K)...............  $   84
Excess projected benefit obligation over the fair value of
  pension plan assets (as reported in Cyprus Amax's December
  31, 1998, Form 10-K, comprising a $5 million reduction of
  prepaid expenses and other assets and a $52 million
  increase in other liabilities and deferred credits).......  $   57
Excess fair value of pension plan assets over the projected
  benefit obligation (as reported in Asarco's December 31,
  1998, Form 10-K)..........................................  $   10
Reduction in deferred tax liabilities (Note E)..............  $  253
Reduction in net property plant and equipment (derived).....  $1,037
</TABLE>

          (D) The pro forma adjustments reflect the redemption of all 4,664,000
     outstanding shares of Cyprus Amax's Series A Preferred Stock which are
     redeemable at Cyprus Amax's option at $52.40 per share and the issuance by
     Phelps Dodge of $244 million of ten-year debt to finance the redemption.
     Interest is estimated to be fixed at 7.75% resulting in annual interest
     expense of $19 million. The interest rate estimate was based upon ten-year
     treasury bill rates at August 17, 1999, plus Phelps Dodge's indicative rate
     basis points. A change in the interest rate on the debt by 1/8 percent
     would impact annual interest expense by approximately $300,000. Debt issue
     costs are estimated to be approximately $5 million with annual amortization
     of approximately $500,000.

          (E) The estimated income tax effect of the pro forma adjustments have
     been recorded based upon the estimated effective tax rates of approximately
     32% for Asarco and 15% for Cyprus Amax which rates have been derived from
     public quarterly and annual filings of Asarco and Cyprus Amax. The business
     combinations are expected to be tax-free transactions with Asarco's and
     Cyprus Amax's historical tax bases surviving for income tax reporting
     purposes.

                                       66
<PAGE>   74
              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                 COMBINED FINANCIAL INFORMATION -- (CONTINUED)

          Provisions for pro forma income tax expense have been recorded for pro
     forma adjustments to the Pro Forma Combined Statements of Operations
     resulting from pro forma purchase price allocation adjustments and other
     items.

          Cyprus Amax has reported $176 million of U.S. net operating loss
     carryforwards through 1998, expiring from 1999 to 2012, which along with
     other deferred tax assets are subject to an existing valuation allowance.
     Asarco has reported $573.7 million of net loss carryforwards, which expire
     if unused from 2008 through 2018. The net operating loss carryforwards may
     be subject to annual limitations after the acquisitions because of the
     change in ownership rules. The annual limits will be calculated as the
     long-term tax exempt rate (currently 5.18%) times the separate fair market
     values of Cyprus Amax and Asarco, with Asarco's value potentially
     determined without SPCC. Once all facts are known, the annual limits may
     necessitate an increase in the consolidated valuation allowance for
     deferred tax assets.

          Pro forma income tax expense and deferred tax allocations recorded
     upon consummation of the business combinations could vary significantly
     from the pro forma estimates because information regarding Asarco's and
     Cyprus Amax's income tax reporting is not available to Phelps Dodge.

           (F) This pro forma adjustment reflects the issue of 44,660,000 shares
     of Phelps Dodge common stock in connection with the exchange offers for all
     the outstanding common shares of Asarco and Cyprus Amax. The common stock
     of Phelps Dodge represents common shares of $279 million at $6.25 per share
     par value and capital in excess of par of $2,342 million. No common shares
     have been included for the potential share issues in connection with the
     outstanding stock options of Asarco and Cyprus Amax.

           (G) These pro forma adjustments eliminate the historical
     shareholders' equity accounts of Asarco and Cyprus Amax.

           (H) This pro forma adjustment records the estimated reduction in
     depreciation, depletion and amortization expense related to the pro forma
     reduction in property, plant and equipment recorded in connection with the
     business combination purchase price allocation. Because neither fair value
     nor book value information regarding the composition of Asarco's or Cyprus
     Amax's property, plant and equipment is available to Phelps Dodge, actual
     adjustments to depreciation, depletion and amortization expense could
     differ substantially from these estimates.

           (I) Phelps Dodge holds a 14.0% equity interest in Southern Peru
     Copper Corporation (SPCC) which is accounted for as a cost basis investment
     with a book value of $13.2 million at June 30, 1999. Asarco reports a 54.3%
     equity interest in SPCC which it consolidated in both its June 30, 1999,
     Form 10-Q and December 31, 1998, Form 10-K. As a result of Phelps Dodge's
     increased ownership in SPCC that would arise through the acquisition of
     Asarco, Phelps Dodge would qualify for use of the consolidation method of
     reporting for its investment in SPCC. Accordingly, a pro forma adjustment
     is recorded to consolidate Phelps Dodge's interest in SPCC including the
     elimination of Phelps Dodge's cost basis investment in SPCC and its
     recognition of dividend income from SPCC, the reduction of minority
     interests in consolidated subsidiaries representing Phelps Dodge's 14.0%
     interest, and the retroactive restatement of Phelps Dodge's retained
     earnings.

           (J) This pro forma adjustment recognizes imputed interest expense
     resulting from the fair value adjustment of Asarco's long-term debt as
     reported in the Form S-4 Registration Statement of Asarco Cyprus
     Incorporated filed August 20, 1999. A pro forma adjustment to recognize
     imputed interest resulting from the $42 million fair value adjustment of
     Cyprus Amax's debt has not been provided because information necessary to
     calculate such adjustment is not reasonably available to Phelps Dodge.

                                       67
<PAGE>   75
              COMBINATION OF PHELPS DODGE, ASARCO AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                 COMBINED FINANCIAL INFORMATION -- (CONTINUED)

           (K) Pro forma weighted average common stock and common stock
     equivalents outstanding are estimated as follows (in millions):

<TABLE>
<CAPTION>
                                             SIX MONTHS          YEAR ENDED
                                           ENDED JUNE 30,       DECEMBER 31,
                                                1999                1998
                                          ----------------    ----------------
                                          BASIC    DILUTED    BASIC    DILUTED
                                          -----    -------    -----    -------
<S>                                       <C>      <C>        <C>      <C>
Average number of Phelps Dodge common
  shares outstanding....................  57.8       57.8     58.2       58.5
Phelps Dodge common shares to be issued
  in connection with the business
  combination (Note 2)..................  44.7       44.7     44.7       44.7
                                          -----     -----     -----     -----
                                          102.5     102.5     102.9     103.2
                                          =====     =====     =====     =====
</TABLE>

          The average number of common shares outstanding does not give effect
     to Asarco's and Cyprus Amax's outstanding stock options or other common
     stock equivalents, which cannot be estimated because information is not
     available to Phelps Dodge. Based upon public information reported and the
     current exchange offer ratios, Phelps Dodge estimates that the incremental
     number of Phelps Dodge shares issueable upon the exercise of Cyprus Amax
     and Asarco stock options is approximately 3 million.

                                       68
<PAGE>   76

                            PHELPS DODGE CORPORATION

                   PRO FORMA COMBINED STATEMENT OF OPERATIONS
                     PHELPS DODGE AND CYPRUS AMAX COMBINED
                     FOR THE SIX MONTHS ENDED JUNE 30, 1999
                                  (UNAUDITED)
              (AMOUNTS IN MILLIONS, EXCEPT PER SHARE INFORMATION)

<TABLE>
<CAPTION>
                                               HISTORICAL
                                       --------------------------    PRO FORMA    PRO FORMA
                                       PHELPS DODGE   CYPRUS AMAX   ADJUSTMENTS   COMBINED
                                       ------------   -----------   -----------   ---------
<S>                                    <C>            <C>           <C>           <C>
Sales and other operating revenues...     $1,354          561            --         1,915
                                          ------          ---          ----         -----
Operating costs and expenses
  Cost of products sold..............      1,073          428            --         1,501
  Depreciation, depletion
     and amortization................        144          104            (4)(H)       244
  Selling and general administrative
     expense.........................         60           34            --            94
  Exploration and research expense...         21            8            --            29
  Non-recurring charges and provision
     for asset dispositions*.........         83           --            --            83
                                          ------          ---          ----         -----
                                           1,381          574            (4)        1,951
                                          ------          ---          ----         -----
Operating income (loss)..............        (27)         (13)            4           (36)
  Interest expense...................        (48)         (69)           (9)(D)      (126)
  Capitalized interest...............         --            2            --             2
  Miscellaneous income and
     expense, net....................         (7)         (11)            8(A)        (10)
                                          ------          ---          ----         -----
Income (loss) before taxes, minority
  interests and equity in net
  earnings of affiliated companies...        (82)         (91)            3          (170)
  Provision for taxes on income......         19           14            (1)(E)
                                                                         (1)(A)        31

  Minority interests in consolidated
     subsidiaries....................          1           --            --             1
  Equity in net earnings (losses) of
     affiliated companies............          5           --            (7)(A)        (2)
                                          ------          ---          ----         -----
Income (loss) from continuing
  operations.........................        (57)         (77)           (6)         (140)
  Preferred stock dividends..........         --           (9)            9(D)         --
                                          ------          ---          ----         -----
Income (loss) from continuing
  operations applicable to common
  shares.............................     $  (57)         (86)            3          (140)
                                          ======          ===          ====         =====
Net earnings (loss) per share
  Basic..............................     $(0.98)                                   (1.62)
  Diluted............................     $(0.98)                                   (1.62)
Weighted average shares outstanding
  Basic..............................       57.8                                     86.2
  Diluted............................       57.8                                     86.2
</TABLE>

- ------------
* See historical financial statements incorporated by reference in this
  prospectus for a description of non-recurring charges and provision for asset
  dispositions.

                                       69
<PAGE>   77

                            PHELPS DODGE CORPORATION

                   PRO FORMA COMBINED STATEMENT OF OPERATIONS
                     PHELPS DODGE AND CYPRUS AMAX COMBINED
                      FOR THE YEAR ENDED DECEMBER 31, 1998
                                  (UNAUDITED)
              (AMOUNTS IN MILLIONS, EXCEPT PER SHARE INFORMATION)

<TABLE>
<CAPTION>
                                            HISTORICAL
                                    ---------------------------     PRO FORMA     PRO FORMA
                                    PHELPS DODGE    CYPRUS AMAX    ADJUSTMENTS    COMBINED
                                    ------------    -----------    -----------    ---------
<S>                                 <C>             <C>            <C>            <C>
Sales and other operating
  revenues........................     $3,064          1,660          (218)(A)      4,506
                                       ------          -----          ----          -----
Operating costs and expenses
Cost of products sold.............      2,361          1,087          (200)(A)      3,248
  Depreciation, depletion and
     amortization.................        293            254            (7)(A)
                                                                        (6)(H)        534
  Selling and general
     administrative expense.......        123            105            --            228
  Exploration and research
     expense......................         55             45            --            100
  Non-recurring charges and
     provision for asset
     dispositions*................       (191)           118            --            (73)
                                       ------          -----          ----          -----
                                        2,641          1,609          (213)         4,037
                                       ------          -----          ----          -----
Operating income (loss)...........        423             51            (5)           469
  Interest expense................        (97)          (157)          (19)(D)       (273)
  Capitalized interest............          2              2            --              4
  Miscellaneous income and
     expense, net.................          9             17            --             26
                                       ------          -----          ----          -----
Income (loss) before taxes,
  minority interests and equity in
  net earnings of affiliated
  companies.......................        337            (87)          (24)           226
  Provision for taxes on income...       (134)           (11)            4(E)        (141)
  Minority interests in
     consolidated subsidiaries....         (8)             1            --             (7)
  Equity in net earnings (losses)
     of affiliated companies......         (4)           (53)           --            (57)
                                       ------          -----          ----          -----
Income (loss) from continuing
  operations......................        191           (150)          (20)            21
  Preferred stock dividends.......         --            (19)           19(D)          --
                                       ------          -----          ----          -----
Income (loss) from continuing
  operations applicable to common
  shares..........................     $  191           (169)           (1)            21
                                       ======          =====          ====          =====
Net earnings (loss) per share
  Basic...........................     $ 3.28                                        0.24
  Diluted.........................     $ 3.26                                        0.24
Weighted average shares
  outstanding
  Basic...........................       58.2                                        86.6
  Diluted.........................       58.5                                        86.9
</TABLE>

- ------------
* See historical financial statements incorporated by reference in this
  prospectus for a description of non-recurring charges and provision for asset
  dispositions.

                                       70
<PAGE>   78

                            PHELPS DODGE CORPORATION

                        PRO FORMA COMBINED BALANCE SHEET
                     PHELPS DODGE AND CYPRUS AMAX COMBINED
                                 JUNE 30, 1999
                                  (UNAUDITED)
                             (AMOUNTS IN MILLIONS)

<TABLE>
<CAPTION>
                                                   HISTORICAL
                                           --------------------------    PRO FORMA    PRO FORMA
                                           PHELPS DODGE   CYPRUS AMAX   ADJUSTMENTS   COMBINED
                                           ------------   -----------   -----------   ---------
<S>                                        <C>            <C>           <C>           <C>
ASSETS
  Cash and cash equivalents..............     $  144         1,275           (20)(B)
                                                                             (45)(C)
                                                                              (5)(D)    1,349
  Accounts receivable, net...............        396            37            --          433
  Inventories............................        263           239             4(C)       506
  Supplies...............................        104            55            --          159
  Prepaid expenses.......................         15            74            (5)(C)       84
  Deferred income taxes..................         45            32            --           77
                                              ------         -----        ------        -----
    Current assets.......................        967         1,712          (71)        2,608
  Investments and long-term accounts
    receivable...........................         95           328             9(A)       432
  Property, plant and equipment, net.....      3,501         2,546           (90)(C)    5,957
  Other assets and deferred charges......        339           160            (9)(A)
                                                                               5(D)       495
                                              ------         -----        ------        -----
         Total Assets....................     $4,902         4,746          (156)       9,492
                                              ======         =====        ======        =====
LIABILITIES
  Short-term debt........................     $  214           249            --          463
  Current portion of long-term debt......         62            79            --          141
  Accounts payable and accrued
    expenses.............................        456           324            --          780
  Dividends payable......................         29             9            --           38
  Accrued income taxes...................         11            81            --           92
                                              ------         -----        ------        -----
    Current liabilities..................        772           742            --        1,514
  Long-term debt.........................        801         1,499           244(D)
                                                                             (42)(C)    2,502
  Deferred income taxes..................        493            14           (15)(E)      492
  Other liabilities and deferred
    credits..............................        376           412            52(C)       840
                                              ------         -----        ------        -----
                                               2,442         2,667           239        5,348
                                              ------         -----        ------        -----
Minority interests in consolidated
  subsidiaries...........................         86            20            --          106
                                              ------         -----        ------        -----
Common shareholders' equity
  Common shares..........................        362             1            (1)(G)
                                                                             177(F)       539
  Treasury shares........................         --           (86)           86(A)        --
  Preferred shares.......................         --             5            (5)(D)       --
  Capital in excess of par value.........          5         2,912           (86)(A)
                                                                          (2,826)(G)
                                                                           1,487(F)     1,492
  Retained earnings......................      2,198          (768)          768(G)     2,198
  Accumulated other comprehensive income
    (loss)...............................       (183)           (5)            5(G)      (183)
  Other..................................         (8)           --            --           (8)
                                              ------         -----        ------        -----
         Total Shareholders' Equity......      2,374         2,059          (395)       4,038
                                              ------         -----        ------        -----
         Total Liabilities and
           Shareholders' Equity..........     $4,902         4,746          (156)       9,492
                                              ======         =====        ======        =====
</TABLE>

                                       71
<PAGE>   79

                  COMBINATION OF PHELPS DODGE AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                         COMBINED FINANCIAL INFORMATION

1.  BASIS OF PRESENTATION

     The Unaudited Pro Forma Combined Financial Information has been derived
from historical consolidated financial statements of Phelps Dodge and Cyprus
Amax incorporated by reference into this prospectus. See Phelps Dodge "Unaudited
Pro Forma Combined Financial Information" on page 58 of this prospectus.

     The assumptions and related pro forma adjustments described below have been
developed from public historical information available to Phelps Dodge. Pro
forma adjustments have been included only to the extent known and reasonably
available to Phelps Dodge. Additional information may exist that could
materially affect the assumptions and related pro forma adjustments. Such
information is not available to Phelps Dodge because it is within the particular
and singular knowledge of Cyprus Amax.

2.  THE OFFER

     Phelps Dodge is proposing a business combination of Phelps Dodge and Cyprus
Amax through a separate offering to exchange all the issued and outstanding
Cyprus Amax common shares for Phelps Dodge common shares. See "The Offer" on
page 32 of this prospectus.

     Phelps Dodge proposes to exchange all the issued and outstanding Cyprus
Amax common shares for Phelps Dodge common shares at an exchange ratio of 0.3135
Phelps Dodge common share for each Cyprus Amax common share.

     The transaction would be accounted for under the purchase method. The
purchase price for the business combinations is estimated as follows (dollars in
millions and shares in thousands except per share data):

<TABLE>
<CAPTION>
                                                               CYPRUS
                                                                AMAX
                                                              --------
<S>                                                           <C>
Common shares outstanding (as reported in June 30, 1999,
  Form 10-Q)................................................    90,454
Exchange offer ratio of Phelps Dodge common shares for each
  common share..............................................    0.3135
Phelps Dodge common shares to be issued.....................    28,357
Market price of each Phelps Dodge common share on August 20,
  1999, prior to trading halt...............................  $58.6875
                                                              ========
Fair value of Phelps Dodge common shares issued, comprising
  par value of $177 ($6.25 per share) and capital in excess
  of par of $1,487..........................................  $  1,664
Redemption of Cyprus Amax Series A Preferred Stock (Note
  3D).......................................................       244
Estimated transaction costs.................................        20
                                                              --------
Purchase price..............................................  $  1,928
                                                              ========
</TABLE>

     The final purchase price could change materially from the purchase price
estimated above as a result of changes in the market price of common shares of
Phelps Dodge and/or the relative market price of Cyprus Amax common shares.
There are arrangements in place at Cyprus Amax that could impact the purchase
price including employment agreements, change of control severance agreements,
stock appreciation rights, and certain pension and other employee benefit plans.
In addition, actions may be taken by the management of Cyprus Amax, in a
defensive posture or for other reasons, that could impact the purchase price
including amending existing agreements or issuing stock options and other
similar bonus awards. The potential impact of these factors cannot be estimated
but could be material.

     The estimated purchase price does not give effect to outstanding stock
options which could impact the number of Phelps Dodge shares issued and/or the
purchase price either by their exercise or their conversion to

                                       72
<PAGE>   80
                  COMBINATION OF PHELPS DODGE AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                  COMBINED FINANCIAL INFORMATION--(CONTINUED)

outstanding stock options of Phelps Dodge. Such effects prior to completion of
the business combination cannot be reasonably estimated from available public
information. As reported in its December 31, 1998, Form 10-K, Cyprus Amax had
6,346,801 stock options outstanding of which 2,024,009 had weighted average
exercise prices less than the per share equivalent value of Cyprus Amax common
stock as determined by the terms of the exchange offer. If Cyprus Amax's
2,024,009 stock options were exercised prior to consummation of the business
combination, the estimated purchase price would be increased by approximately
$37 million which would be substantially offset by cash and cash equivalents
received as proceeds from such exercises. Although it is Phelps Dodge's desire
that all outstanding Cyprus Amax stock options be converted to Phelps Dodge
stock options at the respective offering exchange ratio, it is not assured
whether such conversions can be achieved in whole or in part nor, consequently,
the potential effect on the purchase price.

     The estimated purchase price does not include any effect of Cyprus Amax's
outstanding preferred share purchase rights. As described in its December 31,
1998, Form 10-K, Cyprus Amax issued in February 1999 one preferred purchase
right for each share of common stock which confers certain rights to the holder
including certain rights in the event of an acquisition of 15% or more of Cyprus
Amax's common stock.

     The final determination of the purchase price may differ from the amount
assumed in the Unaudited Pro Forma Combined Financial Information and that
difference may be material.

3.  PRO FORMA ASSUMPTIONS AND ADJUSTMENTS

     The following assumptions and related pro forma adjustments give effect to
the proposed business combination of Phelps Dodge and Cyprus Amax as if such
combination occurred on January 1, 1998, in the Unaudited Pro Forma Combined
Statements of Operations for the six-month interim period ended June 30, 1999,
and for the year ended December 31, 1998, respectively, and on June 30, 1999,
for the Unaudited Pro Forma Combined Balance Sheet.

     The Unaudited Pro Forma Combined Financial Information is provided for
illustrative purposes only and does not purport to represent what the actual
consolidated results of operations or the consolidated financial position of
Phelps Dodge would have been had the business combination with Cyprus Amax
occurred on the respective dates assumed, nor is it necessarily indicative of
future consolidated operating results or financial position.

     Future cash cost savings are not recognized in this Unaudited Pro Forma
Combined Financial Information. Non-recurring items related to 1998 and the
six-month interim period ended June 30, 1999 are included (see "Selected
Historical Financial Data" at pages 51 through 55 for a summary of non-recurring
items and special charges).

          (A) Reclassifications have been made to the Cyprus Amax historical
     consolidated financial information to conform to Phelps Dodge's
     presentation. The historical financial information of Cyprus Amax excludes
     the results of operations and assets of its discontinued Coal segment as
     reported for 1998 operations in Cyprus Amax's Form 8-K dated June 30, 1999,
     and as reported as of and for the six months ended June 30, 1999, in its
     Form 10-Q filing for such period. Cyprus Amax's historical financial
     information for the year ended December 31, 1998, also has been adjusted to
     exclude the identifiable results of recurring operations of its Lithium
     segment which was sold in October 1998.

                                       73
<PAGE>   81
                  COMBINATION OF PHELPS DODGE AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                  COMBINED FINANCIAL INFORMATION--(CONTINUED)

<TABLE>
<CAPTION>
                                BALANCE SHEET     SIX MONTHS       YEAR ENDED
                                 AT JUNE 30,         ENDED        DECEMBER 31,
                                    1999         JUNE 30, 1999        1998
                                -------------    -------------    ------------
                                               (IN $ MILLIONS)
<S>                             <C>              <C>              <C>
Reclassification adjustments:
  Investments and notes
     receivable...............         9
  Other assets and deferred
     charges..................        (9)
  Treasury shares.............        86
  Capital in excess of par
     value....................       (86)
  Miscellaneous income and
     expense, net.............                         8
  Provision for taxes on
     income...................                        (1)
  Equity in net earnings
     (losses) of affiliated
     companies................                        (7)
Elimination of recurring
  results from sold Lithium
  segment:
  Sales and other operating
     revenues.................                                        (218)
  Cost of products sold
     (derived)................                                        (200)
  Depreciation, depletion and
     amortization expense.....                                          (7)
</TABLE>

          (B) Phelps Dodge estimates it will incur approximately $20 million of
     transaction costs, consisting primarily of investment bankers, attorneys
     and accountant fees, and financial printing and other charges. These
     estimates are preliminary and therefore are subject to change.

          (C) If the business combination is consummated, it will be accounted
     for using the purchase method of accounting in accordance with generally
     accepted accounting principles. Accordingly, the assets and liabilities of
     Cyprus Amax would be recorded at their estimated fair values.

          Phelps Dodge has not had access to information that is within the
     peculiar knowledge of Cyprus Amax and has not performed its due diligence
     necessary to determine the fair value of its assets or liabilities or to
     identify unknown liabilities or obligations. Pro forma adjustments to
     allocate the purchase price have been recorded in the Unaudited Pro Forma
     Combined Financial Information on the basis of fair values reported for
     certain assets and liabilities in public information of Cyprus Amax.
     Because fair value information for the remaining assets and liabilities and
     any possible identifiable intangible assets are not reasonably available to
     Phelps Dodge, the excess of the historical net book values of Cyprus Amax's
     assets acquired over the estimated purchase price has been allocated as a
     reduction of its combined net property, plant and equipment.

          Additionally, Phelps Dodge believes that cost savings will be realized
     upon the consolidation and integration of Cyprus Amax. Phelps Dodge has not
     developed formal plans for combining the operations. Accordingly,
     additional liabilities may be incurred in connection with the business
     combination and any ultimate restructuring. These additional liabilities
     and costs have not been contemplated in the Unaudited Pro Forma Combined
     Financial Information because information necessary to reasonably estimate
     such costs and to formulate detailed restructuring plans is not available
     to Phelps Dodge. Accordingly, the allocation of the purchase price cannot
     be estimated with a reasonable degree of accuracy and may differ materially
     from the amounts assumed in the Unaudited Pro Forma Combined Financial
     Information.

                                       74
<PAGE>   82
                  COMBINATION OF PHELPS DODGE AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                  COMBINED FINANCIAL INFORMATION--(CONTINUED)

          The merger agreement by and between Asarco and Cyprus Amax has a $45
     million termination fee under certain circumstances. If such fee is
     required to be paid upon consummation of Phelps Dodge's proposed
     acquisition of Cyprus Amax, cash and cash equivalents of Cyprus Amax would
     be decreased by the fee payment which in turn would impact the purchase
     price allocation. The Unaudited Pro Forma Combined Financial Information
     has been adjusted to give effect to payment of the termination fee.

          The pro forma purchase price allocation adjustments are estimated as
     follows (in millions):

<TABLE>
<S>                                                           <C>
Reduction of debt to fair value (as reported in Cyprus
  Amax's June 30, 1999, Form 10-Q)..........................  $42
Increase in LIFO based inventory to replacement cost (as
  reported in Cyprus Amax's December 31, 1998, Form 10-K)...  $ 4
Excess projected benefit obligation over the fair value of
  pension plan assets (as reported in Cyprus Amax's December
  31, 1998, Form 10-K, comprising a $5 million reduction of
  prepaid expenses and other assets and a $52 million
  increase in other liabilities and deferred credits).......  $57
Reduction in deferred tax liabilities (Note E)..............  $15
Reduction in net property plant and equipment (derived).....  $90
</TABLE>

          (D) The pro forma adjustments reflect the redemption of all 4,664,000
     outstanding shares of Cyprus Amax's Series A Preferred Stock which are
     redeemable at Cyprus Amax's option at $52.40 per share and the issuance by
     Phelps Dodge of $244 million of ten-year debt to finance the redemption.
     Interest is estimated to be fixed at 7.75% resulting in annual interest
     expense of $19 million. The interest rate estimate was based upon ten-year
     treasury bill rates at August 17, 1999, plus Phelps Dodge's indicative rate
     basis points. A change in the interest rate on the debt by 1/8 percent
     would impact annual interest expense by approximately $300,000. Debt issue
     costs associated with the debt are estimated to be approximately $5 million
     with annual amortization of approximately $500,000.

          (E) The estimated income tax effect of the pro forma adjustments has
     been recorded based upon the estimated effective tax rate of approximately
     15% for Cyprus Amax which rate has been derived from public quarterly and
     annual filings. The business combination is expected to be a tax-free
     transaction with Cyprus Amax's historical tax bases surviving for income
     tax reporting purposes.

          A provision for pro forma income tax expense has been recorded for pro
     forma adjustments to the Pro Forma Combined Statements of Operations
     resulting from pro forma purchase price allocation adjustments and other
     items.

          Cyprus Amax has reported $176 million of U.S. net operating loss
     carryforwards through 1998, expiring from 1999 to 2012, which along with
     other deferred tax assets are subject to an existing valuation allowance.
     The net operating loss carryforwards may be subject to annual limitations
     after the acquisition because of the change in ownership rules. The annual
     limits will be calculated as the long-term tax exempt rate (currently
     5.18%) times the fair market value of Cyprus Amax. Once all facts are
     known, the annual limits may necessitate an increase in the consolidated
     valuation allowance for deferred tax assets.

          Pro forma income tax expense and deferred tax allocations recorded
     upon consummation of the business combination could vary significantly from
     the pro forma estimates because information regarding Cyprus Amax's income
     tax reporting is not available to Phelps Dodge.

          (F) This pro forma adjustment reflects the issue of 28,357,000 shares
     of Phelps Dodge common stock in connection with the exchange offers for all
     the outstanding common shares of Cyprus Amax. The common stock of Phelps
     Dodge represents common shares of $177 million at $6.25 per share par value

                                       75
<PAGE>   83
                  COMBINATION OF PHELPS DODGE AND CYPRUS AMAX

                        NOTES TO THE UNAUDITED PRO FORMA
                  COMBINED FINANCIAL INFORMATION--(CONTINUED)

     and capital in excess of par of $1,487 million. No common shares have been
     included for the potential shares issues in connection with the outstanding
     stock options of Cyprus Amax.

          (G) These pro forma adjustments eliminate the historical shareholders'
     equity accounts of Cyprus Amax.

          (H) This pro forma adjustment records the estimated reduction in
     depreciation, depletion and amortization expense related to the pro forma
     reduction in property, plant and equipment recorded in connection with the
     business combination purchase price allocation. Because neither fair value
     nor book value information regarding the composition of Cyprus Amax's
     property, plant and equipment is available to Phelps Dodge, actual
     adjustments to depreciation, depletion and amortization expense could
     differ substantially from these estimates.

          (I) A pro forma adjustment to recognize imputed interest resulting
     from the $42 million fair value adjustment of Cyprus Amax's debt has not
     been provided because information necessary to calculate such adjustment is
     not reasonably available to Phelps Dodge.

          (J) Pro forma weighted average common stock and common stock
     equivalents outstanding are estimated as follows (in millions):

<TABLE>
<CAPTION>
                                         SIX MONTHS          YEAR ENDED
                                       ENDED JUNE 30,       DECEMBER 31,
                                            1999                1998
                                      ----------------    ----------------
                                      BASIC    DILUTED    BASIC    DILUTED
                                      -----    -------    -----    -------
<S>                                   <C>      <C>        <C>      <C>
Average number of Phelps Dodge
  common shares outstanding.........  57.8      57.8      58.2      58.5
Phelps Dodge common shares to be
  issued in connection with the
  business combination (Note 2).....  28.4      28.4      28.4      28.4
                                      ----      ----      ----      ----
                                      86.2      86.2      86.6      86.9
                                      ====      ====      ====      ====
</TABLE>

     The average number of common shares outstanding does not give effect to
Cyprus Amax's outstanding stock options or other common stock equivalents, which
cannot be estimated because information is not available to Phelps Dodge. Based
upon public information reported and the current exchange offer ratio, Phelps
Dodge estimates that the incremental number of Phelps Dodge shares issueable
upon the exercise of Cyprus Amax stock options is approximately 3 million.

                                       76
<PAGE>   84

                   DESCRIPTION OF PHELPS DODGE CAPITAL STOCK

     The following description of the terms of the capital stock of Phelps Dodge
is not meant to be complete and is qualified by reference to Phelps Dodge's
Restated Certificate of Incorporation (the Phelps Dodge charter), which is
incorporated herein by reference. See "Where You Can Find Additional
Information."

AUTHORIZED CAPITAL STOCK

     Under the Phelps Dodge charter, Phelps Dodge's authorized capital stock
consists of 200,000,000 shares of Phelps Dodge common stock, par value $6.25 per
share, and 6,000,000 shares of Phelps Dodge preferred stock, par value $1.00 per
share.

PHELPS DODGE COMMON STOCK

     Phelps Dodge Common Stock Outstanding.  The outstanding shares of Phelps
Dodge common stock are, and the shares of Phelps Dodge common stock issued
pursuant to the exchange offers will be, duly authorized, validly issued, fully
paid and nonassessable.

     Voting Rights.  Each holder of Phelps Dodge common stock is entitled to one
vote for each share of Phelps Dodge common stock held of record on the
applicable record date on all matters submitted to a vote of shareholders.

     Dividend Rights; Rights upon Liquidation.  The holders of Phelps Dodge
common stock are entitled to receive, from funds legally available for the
payment thereof, dividends when and as declared by resolution of the Phelps
Dodge Board of Directors, subject to any preferential dividend rights granted to
the holders of any outstanding Phelps Dodge preferred stock. In the event of
liquidation, each share of Phelps Dodge common stock is entitled to share pro
rata in any distribution of Phelps Dodge's assets after payment or providing for
the payment of liabilities and the liquidation preference of any outstanding
Phelps Dodge preferred stock.

     Preemptive Rights.  Holders of Phelps Dodge common stock have no preemptive
rights to purchase, subscribe for or otherwise acquire any unissued or treasury
shares or other securities.

PHELPS DODGE PREFERRED STOCK

     Phelps Dodge Preferred Stock Outstanding.  As of the date of this
prospectus, no shares of Phelps Dodge preferred stock were issued and
outstanding.

     Authorized Preferred Stock.  Under Phelps Dodge's charter, the Phelps Dodge
Board of Directors has the authority, without shareholder approval, to create
one or more classes or series within a class of preferred stock, to issue shares
of preferred stock in such class or series up to the maximum number of shares of
the relevant class or series of preferred stock authorized, and to determine the
preferences, rights, privileges and restrictions of any such class or series,
including the dividend rights, voting rights, the rights and terms of
redemption, the rights and terms of conversion, liquidation preferences, the
number of shares constituting any such class or series and the designation of
such class or series.

     The Phelps Dodge Board of Directors has designated a series of preferred
stock as Junior Participating Cumulative Preferred Shares, and has issued rights
to purchase those shares which are exercisable only upon the occurrence of
certain events described below under "Comparison of Rights of Holders of Phelps
Dodge Shares and Cyprus Amax Shares -- Comparison of Charter and By-law
Provisions -- Capitalization."

TRANSFER AND DIVIDEND PAYING AGENT AND REGISTRAR


     ChaseMellon Shareholder Services, L.L.C. is the transfer and dividend
paying agent and registrar for the Phelps Dodge common stock.


                                       77
<PAGE>   85

                       COMPARISON OF RIGHTS OF HOLDERS OF
                   PHELPS DODGE SHARES AND CYPRUS AMAX SHARES

     Upon completion of our proposed business combination, the shareholders of
Cyprus Amax will become shareholders of Phelps Dodge, rather than shareholders
of Asarco Amax. As Phelps Dodge shareholders, the rights of former Cyprus Amax
shareholders will be governed by Phelps Dodge's charter and by-laws, which
differ in certain material respects from Cyprus Amax's charter and by-laws. In
addition, New York is the jurisdiction of incorporation of Phelps Dodge, while
Delaware is the jurisdiction of incorporation of Cyprus Amax. As Phelps Dodge
shareholders, the rights of former Cyprus Amax shareholders will therefore be
governed by the New York Business Corporation Law (NYBCL) instead of the
Delaware General Corporation Law (DGCL).

     The following is a comparison of:

     - the current rights of Cyprus Amax shareholders under the DGCL and the
       Cyprus Amax charter and by-laws; and

     - the rights Cyprus Amax shareholders would have as Phelps Dodge
       shareholders under the NYBCL and the Phelps Dodge charter and by-laws
       upon the consummation of a business combination between Phelps Dodge and
       Cyprus Amax.

     The comparison summarizes the material differences but is not intended to
list all differences and is qualified by reference to New York law, Delaware
law, the Phelps Dodge charter and by-laws and the Cyprus Amax charter and
by-laws. The summary of the Cyprus Amax charter and by-laws is derived from the
disclosure in the Form S-4 filed by Asarco Cyprus Incorporated on August 20,
1999.

COMPARISON OF CHARTER AND BY-LAW PROVISIONS

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
BOARD OF DIRECTORS
Classified Board               Divided into three classes,      Divided into three classes,
                               as nearly equal in number as     as nearly equal in number as
                               possible, with each class        possible, with each class
                               serving a staggered              serving a staggered
                               three-year term.                 three-year term.
Removal of Directors           Under Cyprus Amax's charter      A director may be removed by
                               and by-laws, a director may      the stockholders only for
                               be removed only for cause,       cause.
                               and only by the affirmative
                               vote of holders of 75% of the
                               outstanding voting stock. The
                               DGCL generally provides that
                               directors may be removed,
                               with or without cause, by
                               stockholder majority vote. An
                               exception applies to
                               corporations with classified
                               boards like Cyprus Amax.
                               Unless the charter provides
                               otherwise, stockholders of
                               such a corporation may remove
                               directors only for cause.
Filling of Board Vacancies     With some exceptions,            Vacancies on the board of
                               vacancies on the board may be    directors may be filled only
                               filled by majority vote of       by vote of the directors.
                               the remaining directors then
                               in office.
</TABLE>

                                       78
<PAGE>   86

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
Size of Board                  Board must consist of not        Board must consist of not
                               less than three directors, as    less than 9 nor more than 12
                               fixed from time to time by       directors, as fixed from time
                               resolution of the board. The     to time by resolution of the
                               current number of directors      board. The current number of
                               is 10.                           directors is 11.
STOCKHOLDER MEETINGS
Annual Meeting                 Held on date fixed by board.     Held on the first Wednesday
                                                                in May, or on another date
                                                                fixed by the board from time
                                                                to time.
Calling a Special Meeting      Only the Chairman of the         Only the board of directors
                               Board, the President, the        or the Chairman of the Board
                               board of directors or the        may call a special meeting.
                               holders of a majority of the
                               voting stock may call a
                               special meeting.
Quorum Requirements            The presence, in person or by    Generally, the presence, in
                               proxy, of the holders of         person or by proxy, of the
                               33 1/3% of the outstanding       holders of a majority of the
                               voting stock constitutes a       shares entitled to vote at
                               quorum at the meeting.           the meeting constitutes a
                                                                quorum for that meeting.
Certain Voting Requirements    Stockholder action approving     Phelps Dodge's charter and
                               a merger or consolidation or     by- laws contain no
                               a sale of all or                 comparable supermajority
                               substantially all of Cyprus      voting requirements. Under
                               Amax's assets requires the       the NYBCL, the consummation
                               affirmative vote by the          by Phelps Dodge of a merger,
                               holders of the majority of       consolidation or disposition
                               outstanding voting stock;        of substantially all of its
                               stockholder action on other      assets requires the approval
                               matters, except for elections    of two- thirds of all the
                               of directors, certain            shares of Phelps Dodge
                               amendments of organizational     entitled to vote on the
                               documents and certain            proposal including, in
                               transactions with the            certain situations, the
                               beneficial owner of more than    affirmative vote by the
                               10% of any class of capital      holders of a majority of all
                               stock of Cyprus Amax,            outstanding shares of each
                               requires affirmative vote of     class or series of shares.
                               the majority of votes cast at    Abstentions have the effect
                               a meeting. Abstentions have      of a vote against a proposed
                               the effect of a vote against     matter only if the
                               a proposed matter only if the    affirmative vote required is
                               affirmative vote required is     that of the majority of the
                               that of the majority of the      total votes represented by
                               total votes represented by       the outstanding voting stock.
                               the outstanding voting stock.
                               Cyprus Amax's charter
                               requires the vote of 75% of
                               the outstanding shares of
                               Cyprus Amax's voting stock,
                               voting together as a single
                               class, for the
</TABLE>

                                       79
<PAGE>   87

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
                               approval of business
                               combinations specified in the
                               charter, including certain
                               transactions involving
                               beneficial owners of 10% or
                               more of Cyprus Amax's
                               outstanding voting stock.
                               Business combinations include
                               any merger or consolidation
                               of Cyprus Amax with any
                               interested stockholder, any
                               sale, lease or other
                               disposition of Cyprus Amax
                               assets having a fair market
                               value of $50 million or more
                               to an interested stockholder,
                               the issuance or transfer of
                               Cyprus Amax securities to an
                               interested stockholder for
                               consideration having a fair
                               market value of $50 million
                               or more, the adoption of any
                               plan or proposal by or on
                               behalf of an interested
                               stockholder for the
                               liquidation or dissolution of
                               Cyprus Amax in which the
                               interested stockholder
                               receives anything other than
                               cash, or any transaction
                               which has the effect of
                               increasing the proportionate
                               share of any class of Cyprus
                               Amax's stock owned by the
                               interested stockholder. The
                               charter's supermajority
                               requirements do not apply if
                               a majority of Cyprus Amax's
                               disinterested directors
                               approve the transaction and
                               certain other conditions are
                               met.
                               Separately, Cyprus Amax's
                               charter precludes Cyprus
                               Amax, among other things,
                               from repurchasing its stock,
                               securities convertible into
                               its stock, or similar
                               securities from an interested
                               stockholder who has
                               beneficially owned such
                               securities for less than two
                               years before the repurchase,
                               without the affirmative vote
                               of a majority of Cyprus
                               Amax's voting stock
                               (excluding voting stock owned
                               by the interested
                               stockholder),
</TABLE>

                                       80
<PAGE>   88

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
                               voting as a single class,
                               subject to some exceptions.
Stockholder Action by Written  Stockholder action must be       Stockholder action must be
  Consent                      taken at an annual or special    taken at an annual or special
                               meeting and not by written       meeting and not by written
                               consent.                         consent, except that the
                                                                NYBCL permits stockholder
                                                                action by unanimous written
                                                                consent.
Advance Notice for             To bring a matter (including     Generally, to bring a matter
  Stockholder Nominations and  the nomination of directors)     (including the nomination of
  Other Business               before an annual meeting, a      directors) before an annual
                               stockholder generally must       meeting, a stockholder must
                               give notice of a proposed        give notice not less than 60
                               matter not less than 90 days     days nor more than 90 days
                               prior to the anniversary of      prior to the meeting, but if
                               the previous year's meeting,     the meeting is scheduled for
                               but if less than 70 days         a day other than the first
                               notice of the annual meeting     Wednesday in May and less
                               is given to stockholders, a      than 70 days' notice is given
                               stockholder must give notice     or prior public announcement
                               of a proposed matter by the      is made to stockholders, a
                               tenth day following the date     stockholder must give notice
                               at which notice of the annual    by the tenth day following
                               meeting was mailed. Cyprus       the date at which notice of
                               Amax's by-laws contain           the annual meeting was mailed
                               requirements as to the form      or announcement thereof made.
                               and content of the notice.       If the number of directors to
                                                                be elected at the election
                                                                meeting is increased or there
                                                                is a vacancy to be filled at
                                                                the election meeting in a
                                                                class of directors whose
                                                                terms do not expire at the
                                                                election meeting and there is
                                                                no public announcement at
                                                                least 70 days prior to the
                                                                election meeting naming all
                                                                of the nominees for director
                                                                or specifying the size of the
                                                                increased board of directors
                                                                or the number of directors to
                                                                be elected, a nominating
                                                                stockholder's notice is
                                                                timely if given by the tenth
                                                                day following the date on
                                                                which the public announcement
                                                                is first made, but only with
                                                                respect to nominees for any
                                                                positions created by the
                                                                increase or vacancy. Phelps
                                                                Dodge's by-laws contain
                                                                requirements as to the form
                                                                and content of the
                                                                stockholder's notice.
</TABLE>

                                       81
<PAGE>   89

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
AMENDMENTS TO ORGANIZATIONAL
  DOCUMENTS
Certificate of Incorporation   Generally may be amended by      Under the NYBCL, subject to
                               board resolutions and the        limited exceptions,
                               affirmative vote by the          amendments to Phelps Dodge's
                               holders of a majority of the     charter must be approved by
                               outstanding voting stock,        vote of a majority of all
                               except that amendments to        outstanding shares entitled
                               provisions relating to the       to vote on the proposed
                               directors, stockholder           amendment, except that
                               nominations and action,          charter provisions requiring
                               by-law amendments, and           a greater or class vote may
                               certain transactions with        only be amended by such vote.
                               beneficial owners of 10% or      In addition, an amendment
                               more of the outstanding          that negatively affects in
                               common stock require the         certain ways holders of
                               affirmative vote of the          shares of a class or series
                               holders of 75% of the            requires authorization by a
                               outstanding voting stock.        majority of the votes of all
                                                                outstanding shares of the
                                                                class or series.
By-laws                        Generally may be amended by      Phelps Dodge's by-laws permit
                               the affirmative vote of the      the amendment of the by-laws
                               holders of a majority of the     by a vote of a majority of
                               voting stock at the relevant     all the directors at any
                               meeting, or by the               regular or special meeting of
                               affirmative vote of a            the board, except that
                               majority of the board.           provisions relating to the
                               Amendments to certain            repurchase of stock by Phelps
                               provisions of Cyprus Amax's      Dodge may only be amended by
                               charter governing the            majority vote of the
                               by-laws, including those         stockholders. Generally,
                               relating to stockholder          under the NYBCL, the by-laws
                               meetings and action, and the     may also be amended by a
                               number, election and removal     majority of the votes cast by
                               of directors, require the        the shares entitled to vote
                               affirmative vote of the          in the election of any
                               holders of 75% of the            directors.
                               outstanding voting stock.
CAPITALIZATION
Authorized Stock               Common stock: 150 million        Common stock: 200 million
                               shares; preferred stock: 20      shares; preferred stock: 6
                               million shares.                  million shares.
Preferred Stock                The board is authorized to       The board is authorized to
                               issue preferred stock from       issue preferred stock from
                               time to time in one or more      time to time in one or more
                               series, with terms to be         series, with terms to be
                               fixed by the board.              fixed by the board.
Rights Plans                   Cyprus Amax has a rights         Phelps Dodge has a rights
                               agreement, dated as of           agreement, dated as of
                               February 28, 1999. The rights    February 5, 1998. The rights
                               agreement triggers upon the      agreement triggers upon the
                               acquisition by a third party     acquisition by a third party
                               of 15% of Cyprus Amax's          of 20% of Phelps Dodge's
</TABLE>

                                       82
<PAGE>   90

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
                               outstanding common stock. The    outstanding common stock. The
                               board may redeem rights at       board may redeem rights at
                               any time prior to the time       any time prior to the time
                               such an acquisition takes        such an acquisition takes
                               place.                           place.
Share Repurchases              Cyprus Amax may generally        The NYBCL prohibits Phelps
                               repurchase its own shares,       Dodge from repurchasing more
                               although there are specific      than 10% of its stock for
                               restrictions on such             more than market value from a
                               repurchases when the seller      stockholder who has held the
                               is a beneficial owner of 10%     stock for less than two
                               or more of the voting power      years, unless the repurchase
                               of the outstanding voting        is approved by the board and
                               stock.                           by majority vote of the
                                                                outstanding voting stock.
                                                                Phelps Dodge's by-laws
                                                                provide that Phelps Dodge may
                                                                repurchase its stock only in
                                                                the regular course of
                                                                legitimate business or for
                                                                the purpose of retiring the
                                                                stock.
EXCULPATION AND                Cyprus Amax's charter            Phelps Dodge's charter
  INDEMNIFICATION OF           provides that no director        provides that the personal
  DIRECTORS, OFFICERS AND      will be personally liable for    liability of Phelps Dodge's
  EMPLOYEES                    damages for breach of            directors for any breach of
                               fiduciary duty, except in        duty in such capacity is
                               cases where the director's       eliminated to the fullest
                               acts or omissions breached       extent permitted by the
                               his duty of loyalty to the       NYBCL. The NYBCL permits
                               corporation or its               Phelps Dodge to eliminate or
                               stockholders, were not in        limit the personal liability
                               good faith or involved           of directors to Phelps Dodge
                               intentional misconduct or a      or its shareholders for
                               knowing violation of law, or     damages for any breach of
                               provided an improper personal    duty in such capacity except
                               benefit to the director.         liability (i) of a director
                                                                (a) whose acts or omissions
                               The Cyprus Amax by-laws          were in bad faith, involved
                               provide that Cyprus Amax will    intentional misconduct or a
                               indemnify any director or        knowing violation of law, (b)
                               officer to the fullest extent    who personally gained a
                               permitted by law if such         financial profit or other
                               director or officer is           advantage to which he or she
                               involved in litigation by        was not legally entitled or
                               reason of the fact that he is    (c) whose acts violated
                               (or was) a director or           certain provisions of New
                               officer, and provide in          York law or (ii) for acts or
                               addition that Cyprus Amax may    omissions prior to the
                               indemnify any person, other      adoption in 1988 of Phelps
                               than a director or officer,      Dodge's charter amendment.
                               if such person is involved in
                               litigation by reason of the      Phelps Dodge's by-laws
                               fact that he is (or was) an      provide that Phelps Dodge
                               employee.                        will indemnify any person
                                                                involved in litigation by
                                                                reason of the fact that he is
                                                                or was a director or officer
                                                                of Phelps Dodge, unless
</TABLE>

                                       83
<PAGE>   91

<TABLE>
<CAPTION>
                                        CYPRUS AMAX                     PHELPS DODGE
                               -----------------------------    -----------------------------
<S>                            <C>                              <C>
                                                                the director's or officer's
                                                                acts were committed in bad
                                                                faith or were the result of
                                                                his active and deliberate
                                                                dishonesty and were material
                                                                to the proceeding or the
                                                                director or officer
                                                                personally gained in fact a
                                                                financial profit or other
                                                                advantage to which he was not
                                                                legally entitled. Further,
                                                                Phelps Dodge's directors and
                                                                officers are covered by
                                                                insurance policies maintained
                                                                against certain liabilities,
                                                                including liabilities arising
                                                                under the Securities Act of
                                                                1933.
</TABLE>

COMPARISON OF CERTAIN STATUTORY PROVISIONS

  APPRAISAL RIGHTS

     CYPRUS AMAX STOCKHOLDER RIGHTS

     Under Delaware law, appraisal rights, or rights of a stockholder to receive
the fair value of his stock in connection with a merger or consolidation, may be
available in connection with a merger or consolidation in certain specific
situations. Appraisal rights are not available to a corporation's stockholders
under Delaware law where the corporation is to be the surviving corporation and
no vote of its stockholders is required to approve the merger.

     In addition, unless otherwise provided in the certificate of incorporation,
no appraisal rights are available under Delaware law to holders of shares of any
class of stock which is either (1) listed on a national securities exchange or
designated as a national market system security on an interdealer quotation
system by NASD or (2) held of record by more than 2,000 stockholders, unless
such stockholders are required by the terms of the merger to accept anything
other than:

     - shares of stock of the surviving corporation;

     - shares of stock of another corporation which, as of the effective date of
       the merger or consolidation, are the kind described in clauses (1) and
       (2) above;

     - cash instead of fractional shares of such stock; or

     - any combination of the consideration described in the three bullet items
       above.

     In addition, appraisal rights are not available under Delaware law in the
event of the sale of all or substantially all of a corporation's assets or the
adoption of an amendment to its certificate of incorporation, unless such rights
are granted in the corporate charter. The Cyprus Amax charter does not grant
such rights.

     PHELPS DODGE STOCKHOLDER RIGHTS

     Under New York law, appraisal rights are generally available in connection
with a merger or consolidation, except that no appraisal rights are available:

     - to the stockholder of a parent corporation merging with its subsidiary
       where the parent owns at least 90% of the subsidiary's outstanding stock
       and certain additional requirements are met;

     - to the stockholder of the surviving corporation in a merger (other than a
       merger described in the previous bullet item) unless the merger adversely
       affects rights of the shares held by the stockholder in a certain way; or

                                       84
<PAGE>   92

     - to a shareholder of shares of any class or series of stock listed on a
       national securities exchange or designated as a national market system
       security on an interdealer quotation system by the National Association
       of Securities Dealers.

Under the statutory provisions described above, since shares of Phelps Dodge
common stock are listed on the New York Stock Exchange, Phelps Dodge common
stockholders are not entitled to appraisal rights in connection with a merger or
consolidation.

     Appraisal rights are also available under the NYBCL in connection with the
sale, lease, exchange or other disposition of all or substantially all of a
corporation's assets other than a transaction wholly for cash where shareholder
approval is conditioned upon the corporation's dissolution and the distribution
of all of the corporation's net assets within one year after the transaction.

     Further, appraisal rights are available in connection with a share exchange
between two corporation as authorized by the NYBCL, except with respect to
shares of a subject corporation that are not acquired in the exchange or that
are listed on a national securities exchange or designated as a national market
system security on an interdealer quotation system by the National Association
of Securities Dealers.

     In addition, appraisal rights are available to a shareholder of a
subsidiary corporation that merges with its parent corporation, or is acquired
by it in a share exchange, where the parent owns at least 90% of the
subsidiary's outstanding stock and certain additional requirements are met.

     Appraisal rights are also available to a shareholder who is not entitled to
vote with respect to a plan of merger or consolidation and whose shares will be
canceled or exchanged in the merger or consolidation for cash or other
consideration other than shares of the surviving or consolidated corporation or
another corporation.

  CERTAIN BUSINESS COMBINATIONS

     CYPRUS AMAX STOCKHOLDER RIGHTS

     Delaware law restricts the ability of certain persons to acquire control of
a Delaware corporation.

     Under the DGGL, if a person acquires 15% or more of the stock of a Delaware
corporation without the approval of the board of directors of that corporation,
thereby becoming an interested stockholder, that person generally may not engage
in certain transactions with the corporation for a period of three years unless
one of the following three exceptions applies:

     - the board of directors approved the acquisition of stock or the
       transaction prior to the time that the person became an interested
       stockholder;

     - upon consummation of the transaction in which the person became an
       interested stockholder, the interested stockholder became an 85% owner of
       the voting stock of the corporation in the transaction, excluding voting
       stock owned by directors who are also officers and certain employee stock
       plans; or

     - the transaction is approved by the board of directors and by the
       affirmative vote of 66 2/3% of the outstanding voting stock which is not
       owned by the interested stockholder.

     The Cyprus Amax charter provides that certain transactions with the
beneficial owner of 10% of the voting power of the outstanding voting stock,
including a merger, significant dispositions of assets, certain issuances or
transfers of securities, certain plans of liquidation and dissolution, and
certain reclassifications of securities, generally require the affirmative vote
of 75% of the voting power of the outstanding shares of stock entitled to vote
in the election of directors, unless Cyprus Amax's disinterested directors
approve the transaction and certain other conditions are met.

     PHELPS DODGE STOCKHOLDER RIGHTS

     New York law restricts the ability of certain persons to acquire control of
a Delaware corporation.

                                       85
<PAGE>   93

     In general, a New York corporation may not engage in a business combination
with an interested stockholder for a period of five years following the
interested stockholder's becoming such. Such a business combination would be
permitted where it is approved by the board of directors prior to the interested
stockholder's becoming such, or within 30 days thereafter, if a good faith
proposal regarding a business combination is made in writing.

     Covered business combinations include certain mergers and consolidations,
dispositions of assets or stock, plans for liquidation or dissolution,
reclassifications of securities, recapitalizations and similar transactions. An
interested stockholder is generally a stockholder owning at least 20% of a
corporation's outstanding voting stock.

     In addition, New York corporations may not engage at any time with any
interested stockholder in a business combination other than:

     - a business combination approved by the board of directors prior to the
       stock acquisition, or where the acquisition of the stock had been
       approved by the board of directors prior to the stock acquisition,

     - a business combination approved by the affirmative vote of the holders of
       a majority of the outstanding voting stock not beneficially owned by the
       interested stockholder at a meeting for that purpose no earlier than five
       years after the stock acquisition, or

     - a business combination in which the interested stockholder pays a formula
       price designed to ensure that all other stockholders receive at least the
       highest price per share paid by the interested stockholder and that meets
       certain other requirements.

     Phelps Dodge is governed by the NYBCL, as described above. Phelps Dodge's
charter does not contain a provision regarding transactions with interested
stockholders.

                                       86
<PAGE>   94

                       ASARCO AND CYPRUS AMAX INFORMATION

     While we have included in this prospectus information concerning Asarco and
Cyprus Amax that is known to us based on publicly available information
(primarily filings by Asarco and Cyprus Amax with the SEC), we are not
affiliated with Asarco or Cyprus Amax and neither Asarco nor Cyprus Amax has
permitted us to have access to their books and records. Therefore, non-public
information concerning Asarco or Cyprus Amax was not available to us for the
purpose of preparing this prospectus. Although we have no knowledge that would
indicate that statements relating to Asarco or Cyprus Amax contained or
incorporated by reference in this prospectus are inaccurate or incomplete, we
were not involved in the preparation of those statements and cannot verify them.

     Pursuant to rule 409 under the Securities Act of 1933 and rule 12b-21 under
the Securities Exchange Act of 1934, we are requesting that Asarco and Cyprus
Amax provide us with information required for complete disclosure regarding the
businesses, operations, financial condition and management of Asarco and Cyprus
Amax. We will amend or supplement this prospectus to provide any and all
information we receive from Asarco or Cyprus Amax, if we receive the information
before our offer expires and we consider it to be material, reliable and
appropriate. In addition, pursuant to rule 439 under the Securities Act, we are
requesting that PricewaterhouseCoopers LLP, the independent accountants of both
Asarco and Cyprus Amax, provide us with the consents required for us to
incorporate by reference into this prospectus the PricewaterhouseCoopers audit
reports included in Asarco's and Cyprus Amax's Annual Reports on Form 10-K for
the year ended December 31, 1998. If we receive those consents, we will promptly
file them as exhibits to our registration statement.

                          FORWARD-LOOKING INFORMATION

     The U.S. securities laws provide a "safe harbor" for certain
forward-looking statements. This prospectus contains forward-looking statements,
including statements concerning the business, future financial position, results
of operations, business strategy, estimated cost savings and other benefits of
our proposed business combination, plans as to dividends and plans and
objectives of management for future operations of Phelps Dodge, Asarco and
Cyprus Amax. Forward-looking statements can be found, among other places, under
"The Proposed Combination," "Reasons for the Proposed Combination," "Background
of the Offer" and "Unaudited Pro Forma Combined Financial Information."
Generally, the words "will," "may," "should," "continue," "believes," "expects,"
"anticipates" or similar expressions identify forward-looking statements.
Forward-looking statements involve risks and uncertainties that could cause
actual results to differ materially from those projected.

     Statements regarding the expected benefits of our proposed business
combination with Asarco and Cyprus Amax, the expected commencement dates of
operations, projected quantities of future production, capital costs, production
rates and other operating and financial data are based on expectations that
Phelps Dodge believes are reasonable, but we can give no assurance that such
expectations will prove to have been correct. Factors that could cause actual
results to differ materially include, among others:

     - risks and uncertainties relating to the timing of completion of the
       proposed Phelps Dodge/Asarco/ Cyprus Amax business combination;

     - the possibility that we will be unable to realize the expected cost
       savings and other benefits from the combination,

     - difficulties related to the integration of the businesses of Phelps
       Dodge, Asarco and Cyprus Amax,

     - the possibility that Phelps Dodge will not be able to combine with both
       Asarco and Cyprus Amax,

     - general U.S. and international economic, financial market and political
       conditions,

     - political and economic risks associated with operations outside the U.S.,

     - the cyclical and volatile price of copper and other metals,

                                       87
<PAGE>   95

     - unanticipated ground, water, weather or operating conditions or force
       majeure events,

     - unanticipated ore grade and geological problems or metallurgical and
       other processing problems,

     - delays in the receipt of or failure to receive necessary government
       permits,

     - changes in laws or regulations or the interpretation and enforcement
       thereof,

     - labor relations and accidents, and

     - environmental risks.

These and other risk factors are discussed in more detail in this prospectus.
See "Risk Factors" beginning on page 6. Many such factors are beyond our ability
to control or predict. Readers are cautioned not to put undue reliance on
forward-looking statements. We disclaim any intent or obligation to update these
forward-looking statements, whether as a result of new information, future
events or otherwise.

                                 LEGAL MATTERS

     The validity of the Phelps Dodge common shares offered hereby will be
passed upon for Phelps Dodge by Debevoise & Plimpton, 875 Third Avenue, New
York, New York.

                                    EXPERTS

     The audited consolidated financial statements of Phelps Dodge incorporated
by reference in this Prospectus have been audited by PricewaterhouseCoopers LLP,
independent public accountants, and are incorporated by reference herein in
reliance upon the authority of said firm as experts in auditing and accounting.

                                       88
<PAGE>   96

                                                                      SCHEDULE A

          DIRECTORS AND EXECUTIVE OFFICERS OF PHELPS DODGE CORPORATION

     The name, business address, present principal occupation or employment and
five-year employment history of each of the directors and executive officers of
Phelps Dodge Corporation are set forth below. Unless otherwise indicated, each
occupation set forth opposite an individual's name refers to employment with
Phelps Dodge and each individual has held such occupation for at least the last
five years. Each director and executive officer listed below is a citizen of the
United States.

<TABLE>
<CAPTION>
                                                           POSITION WITH PHELPS DODGE; PRINCIPAL
                                                             OCCUPATION OR EMPLOYMENT; 5-YEAR
          NAME AND BUSINESS ADDRESS                                 EMPLOYMENT HISTORY
- ---------------------------------------------       ---------------------------------------------------
<S>                                                 <C>
Archie W. Dunham                                    Mr. Dunham has been a Phelps Dodge director since
Conoco, Inc.                                        1998. He has been Chairman of the Board of Conoco,
600 North Dairy Hartford Road                       Inc. (integrated energy company) since 1999 and
Houston, TX 77079-1175                              President and Chief Executive Officer since January
                                                    1996. He was an Executive Vice President of E.I.
                                                    duPont de Nemours and Company (chemical materials
                                                    and energy company), Conoco's former parent, from
                                                    1995 to October 1998. He was a Senior Vice
                                                    President -- DuPont Polymers and DuPont Chemicals
                                                    and Pigments from 1987 to 1992, and an Executive
                                                    Vice President -- Exploration Production of Conoco
                                                    from 1992 to 1995. Mr. Dunham is a director of
                                                    Conoco Inc. and Louisiana Pacific Corporation. Age
                                                    60.

William A. Franke                                   Mr. Franke has been a Phelps Dodge director since
Franke & Company, Inc.                              1980. He has been Chairman and Chief Executive
2525 E. Camelback Road                              Officer of America West Holdings Corporation since
Suite 800                                           February 1997 and Chairman of the Board of its
Phoenix, AZ 85016                                   principal subsidiary, America West Airlines, Inc.
                                                    (airline carrier), since 1992. He was the
                                                    subsidiary's Chief Executive Officer from December
                                                    1993 until February 1997, and its President from
                                                    May 1996 until February 1997. He has been President
                                                    of Franke & Company, Inc., Phoenix, Arizona, an
                                                    investment firm, since 1987. He is a director of
                                                    America West Holdings Corporation, America West
                                                    Airlines, Inc., Central Newspapers, Inc., Beringer
                                                    Wine Estates, Mtel Latin America, Inc., AerFi Group
                                                    Plc, and the Air Transport Association of America.
                                                    Age 62.

Southwood J. Morcott                                Mr. Morcott has been a Phelps Dodge director since
Dana Corporation                                    1991. He has been Chairman of the Board of Dana
4500 Dort St.                                       Corporation (manufacturer and distributor of
Toledo, OH 43615                                    automotive and vehicular parts) since 1990. From
                                                    1987 to 1995, he served as Chairman of Hayes-Dana
                                                    Inc. He was Chief Executive Officer of Dana
                                                    Corporation from 1989 until February 1999, and
                                                    Chief Operating Officer from 1986 until January
                                                    1997. He was President of Dana Corporation from
                                                    1986 to 1995. Mr. Morcott is a director of Dana
                                                    Corporation, CSX Corporation and Johnson Controls,
                                                    Inc. Age 61.
</TABLE>

                                       A-1
<PAGE>   97

<TABLE>
<CAPTION>
                                                           POSITION WITH PHELPS DODGE; PRINCIPAL
                                                             OCCUPATION OR EMPLOYMENT; 5-YEAR
          NAME AND BUSINESS ADDRESS                                 EMPLOYMENT HISTORY
- ---------------------------------------------       ---------------------------------------------------
<S>                                                 <C>
J. Steven Whisler                                   Mr. Whisler has been a Phelps Dodge director since
Phelps Dodge Corporation                            1995 and has been Phelps Dodge's President and
2600 North Central Avenue                           Chief Operating Officer since December 1997, and
Phoenix, AZ 85004-3104                              President of Phelps Dodge Mining Company, a
                                                    division of Phelps Dodge, from 1991 to October
                                                    1998. He was a Senior Vice President of Phelps
                                                    Dodge from 1988 to December 1997 and Vice President
                                                    of Phelps Dodge from 1987 until 1988. He was
                                                    General Counsel of Phelps Dodge from 1987 until
                                                    1991. He is a director of Burlington Northern Santa
                                                    Fe Corporation and Southern Peru Copper
                                                    Corporation. Age 44.

Robert N. Burt                                      Mr. Burt has been a Phelps Dodge director since
FMC Corporation                                     1993. He has been Chairman of the Board and Chief
200 East Randolph Drive                             Executive Officer of FMC Corporation (chemicals and
Chicago, IL 60601                                   machinery for industry, agriculture and government)
                                                    since 1991. He is a director of FMC Corporation and
                                                    Warner-Lambert Company. Age 61.

Robert D. Krebs                                     Mr. Krebs has been a Phelps Dodge director since
Burlington Northern Santa Fe Corporation            1987. He has been Chairman and Chief Executive
2650 Lou Menk Drive                                 Officer of Burlington Northern Santa Fe Corporation
Fort Worth, TX 76131-2830                           (transportation) since June 1, 1999. From April
                                                    1997 to May 31, 1999, he was Chairman, President
                                                    and Chief Executive Officer of Burlington Northern
                                                    Santa Fe Corporation. From September 1995 to April
                                                    1997, he was President and Chief Executive Officer
                                                    of Burlington Northern Santa Fe Corporation. From
                                                    June 1988 to January 1998, he was Chairman,
                                                    President and CEO of Santa Fe Pacific Corporation.
                                                    He is a director of Burlington Northern Santa Fe
                                                    Corporation. Age 57.

Douglas C. Yearley                                  Mr. Yearley has been a Phelps Dodge director since
Phelps Dodge Corporation                            1986 and has been Phelps Dodge's Chairman of the
2600 North Central Avenue                           Board and Chief Executive Officer since 1989. He
Phoenix, AZ 85004-3014                              was President of Phelps Dodge from 1991 until
                                                    December 1997. He was President of Phelps Dodge
                                                    Industries, a division of Phelps Dodge, from 1988
                                                    until 1990, Executive Vice President of Phelps
                                                    Dodge from 1987 until 1989 and Senior Vice
                                                    President of Phelps Dodge from 1982 through 1986.
                                                    He is a director of J. P. Morgan & Co.,
                                                    Incorporated and its principal banking subsidiary,
                                                    Morgan Guaranty Trust Company of New York, Lockheed
                                                    Martin Corporation, USX Corporation and Southern
                                                    Peru Copper Corporation. Age 63.
</TABLE>

                                       A-2
<PAGE>   98


<TABLE>
<CAPTION>
                                                           POSITION WITH PHELPS DODGE; PRINCIPAL
                                                             OCCUPATION OR EMPLOYMENT; 5-YEAR
          NAME AND BUSINESS ADDRESS                                 EMPLOYMENT HISTORY
- ---------------------------------------------       ---------------------------------------------------
<S>                                                 <C>
Paul Hazen                                          Mr. Hazen has been a Phelps Dodge director since
Wells Fargo Bank                                    1988. He has been Chairman of Wells Fargo & Co.
420 Montgomery Street                               since November 1998. He was Chairman and Chief
San Francisco, CA 94104                             Executive Officer of Wells Fargo & Co., San
                                                    Francisco (bank holding company) and of Wells Fargo
                                                    Bank, N.A. (national banking association) from
                                                    January 1995 until November 1998. He was President
                                                    of Wells Fargo & Co. and of Wells Fargo Bank, N.A.
                                                    from 1984 to 1994. He is a director of Wells Fargo
                                                    & Co., Safeway, Inc., Shanghai Commercial Bank
                                                    Ltd., Vodaphone AirTouch Plc and E.piphany, Inc.
                                                    Age 57.

Manuel J. Iraola                                    Mr. Iraola has been a Phelps Dodge director since
Phelps Dodge Corporation                            1997 and has been President of Phelps Dodge
2600 North Central Avenue                           Industries, a division of Phelps Dodge, since 1995,
Phoenix, AZ 85004-3014                              and a Senior Vice President of Phelps Dodge since
                                                    1995. From 1992 until 1995 he was President of
                                                    Phelps Dodge International Corporation. Age 51.

Marie L. Knowles                                    Mrs. Knowles has been a Phelps Dodge director since
ARCO                                                1994. She has been Executive Vice President and
333 South Hope Street                               Chief Financial Officer of Atlantic Richfield
Los Angeles, CA 90071                               Company (diversified energy company) since 1996.
                                                    From 1993 until 1996 she was Senior Vice President
                                                    of Atlantic Richfield Company, and President of
                                                    ARCO Transportation Company, a former subsidiary of
                                                    Atlantic Richfield Company. From 1990 to 1993 she
                                                    was Vice President and Controller of Atlantic
                                                    Richfield Company. Mrs. Knowles is a director of
                                                    Vastar Resources, Inc., URS Corporation and America
                                                    West Holdings Corporation. Age 52.

Gordon R. Parker                                    Mr. Parker has been a Phelps Dodge director since
10101 East Dry Creek Road                           1995. He was Chairman of Newmont Mining Corporation
Englewood, CO 80112                                 from 1986 until his retirement in 1994. He was
                                                    Chief Executive Officer from 1985 until 1993. Mr.
                                                    Parker is a director of Caterpillar, Inc., Gold
                                                    Fields of South Africa, Gold Fields Limited and The
                                                    Williams Companies, Inc. Age 63.

Ramiro G. Peru                                      Mr. Peru has been Chief Financial Officer of Phelps
Phelps Dodge Corporation                            Dodge since May 1999 and has been a Senior Vice
2600 North Central Avenue                           President since 1997. He previously was appointed
Phoenix, AZ 85004-3014                              Vice President of Phelps Dodge Mining Company in
                                                    1993 and Vice President and Treasurer of Phelps
                                                    Dodge in 1995.
</TABLE>


                                       A-3
<PAGE>   99

<TABLE>
<CAPTION>
                                                           POSITION WITH PHELPS DODGE; PRINCIPAL
                                                             OCCUPATION OR EMPLOYMENT; 5-YEAR
          NAME AND BUSINESS ADDRESS                                 EMPLOYMENT HISTORY
- ---------------------------------------------       ---------------------------------------------------
<S>                                                 <C>
Timothy R. Snider                                   Mr. Snider has been a Senior Vice President of
Phelps Dodge Corporation                            Phelps Dodge since 1998. He is also President of
2600 North Central Avenue                           Phelps Dodge Mining Company. Before becoming Senior
Phoenix, AZ 85004-3014                              Vice President, he was a Vice President of Phelps
                                                    Dodge, a position he held since 1997. He was Vice
                                                    President, Arizona operations, of Phelps Dodge
                                                    Mining Company. He previously served as President
                                                    of Phelps Dodge Morenci, Inc.

S. David Colton                                     Mr. Colton has been Vice President and General
Phelps Dodge Corporation                            Counsel of Phelps Dodge since April 1998. Before
2600 North Central Avenue                           that, he was Vice President and Counsel for Phelps
Phoenix, AZ 85004-3014                              Dodge Exploration, a position he held since 1995.
                                                    Prior to that time, he was Senior Exploration
                                                    Counsel for the exploration and development group
                                                    of Phelps Dodge Mining Company.
</TABLE>

              DIRECTORS AND EXECUTIVE OFFICERS OF CAV CORPORATION

     The present directors and executive officers of CAV Corporation are set
forth below, along with their respective positions with CAV. Each of these
individuals is an executive officer of Phelps Dodge Corporation. Further
information concerning each of them is set forth above.

<TABLE>
<S>                                                 <C>
Douglas C. Yearley                                  Director and Chairman
J. Steven Whisler                                   Director and President
Ramiro G. Peru                                      Director, Vice President and Treasurer
S. David Colton                                     Director, Vice President and Secretary
</TABLE>

                                       A-4
<PAGE>   100

                                                                      SCHEDULE B

                    ADDITIONAL INFORMATION REGARDING PHELPS
             DODGE CORPORATION'S EXPLORATION AND MINING PROPERTIES

PD MINING -- EXPLORATION & DEVELOPMENT

     Our exploration group's primary objectives are to increase copper reserves
through discoveries, acquisitions and joint ventures and, where appropriate, to
diversify into other metals, minerals and geographic areas. This group operates
in more than 30 countries and maintains offices in Australia, Austria, Brazil,
Canada, Chile, Eritrea, India, Indonesia, Madagascar, Mexico, Peru, the
Philippines, South Africa, the United States and Zambia.

     The 1998 exploration program continued to place emphasis on the search for
and delineation of large scale copper, gold and other base metal deposits. We
expended $42.0 million on worldwide exploration during 1998, compared with $74.1
million in 1997 and $70.7 million in 1996. Approximately 26 percent of the 1998
expenditures occurred in the United States with 19 percent being spent at our
mine sites. This compares with 33 percent in 1997 (23 percent at mine sites) and
47 percent in 1996 (33 percent at mine sites). The balance of exploration
expenditures was spent principally in Australasia, Brazil, Canada, Chile,
Mexico, Peru and Madagascar.

     During 1998, exploration efforts continued at our existing copper
operations. In New Mexico, additional mine-for-leach reserves were delineated in
the Tyrone area.

     On May 7, 1997, we announced plans to resume production at our Ajo copper
mine in southern Arizona where mining operations have been suspended since 1984.
Environmental permitting is continuing while the project is on hold pending an
improvement in market conditions.

     Environmental permitting is in progress to advance the development of our
Dos Pobres and San Juan deposits in the Safford District in eastern Arizona. The
Dos Pobres deposit contains a total of 286 million tons of leach material with a
grade of 0.39 percent copper. The San Juan deposit contains 272 million tons of
leach material with a grade of 0.28 percent copper. Additionally, the Dos Pobres
deposit contains 330 million tons of concentrator material with a grade of 0.65
percent copper.

     Internationally, our explorations group completed a feasibility study on
the Ambatovy nickel/cobalt deposit in central Madagascar. Detailed drilling in
the district, which is located 80 kilometers east of the capital city of
Antananarivo, defined mineralized material of 210 million tons at 1.1 percent
nickel and 0.1 percent cobalt. Acid consumption by the ore is low, and the ore
is amenable to high pressure acid leach extraction for nickel and cobalt. The
feasibility study indicated there was a need for the price of nickel to increase
to make the project economical.

     We completed a pre-feasibility study on our 70 percent-owned Piedras Verdes
property in Sonora, Mexico, in 1998. Results indicated leachable mineralized
material of 310 million tons at 0.37 percent copper. Metallurgical testwork is
continuing.

     In 1998, we formed a Brazilian joint venture company with Companhia Vale do
Rio Doce (CVRD) under the name Mineracao Serra do Sossego S.A. (Sossego). The
venture agreement required us to spend approximately $4.5 million on exploration
and related activities in order to earn a 50 percent share in the venture.
Having completed our earn-in, the mineral rights and all initial investments
were transferred into the new company in December 1998. The deposit contains an
estimated 200 million tons at 1.2 percent copper with 0.31 grams of gold per
ton. Sossego is starting the necessary work to develop a pre-feasibility study
to further define the mineralized material and determine the viability of the
project.

                                       B-1
<PAGE>   101

ORE RESERVES

     Ore reserves at each of our active copper operations and at Safford, Ajo,
Ojos del Salado and Cobre have been estimated as follows:
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                   ESTIMATED AT DECEMBER 31, 1998                   ESTIMATED AT DECEMBER 31, 1997
                           ----------------------------------------------   -----------------------------------------------
                               MILLING            LEACHING                      MILLING            LEACHING
                               RESERVES           RESERVES        PHELPS        RESERVES           RESERVES         PHELPS
                           ----------------   ----------------    DODGE     ----------------   -----------------    DODGE
                           MILLION     %      MILLION     %      INTEREST   MILLION     %      MILLION      %      INTEREST
                            TONS     COPPER    TONS     COPPER     (%)       TONS     COPPER     TONS     COPPER     (%)
                           -------   ------   -------   ------   --------   -------   ------   --------   ------   --------
<S>                        <C>       <C>      <C>       <C>      <C>        <C>       <C>      <C>        <C>      <C>
Morenci..................   475.8     0.63    2,076.9    0.22      85.0      543.3     0.68    1,628.1     0.26      85.0
Chino....................   350.3     0.62      483.0    0.30      66.7      368.9     0.62      520.8     0.30      66.7
Tyrone...................       -        -      466.3    0.32     100.0          -        -      455.0     0.34     100.0
Cobre....................   133.6     0.73       98.0    0.35     100.0        N/A      N/A        N/A      N/A         -
Candelaria*..............   456.1     0.85          -       -      80.0      475.8     0.88          -        -      80.0
Safford**................   330.0     0.65      558.2    0.34     100.0      330.0     0.65      285.0     0.39     100.0
Ajo......................   150.0     0.56          -       -     100.0      150.0     0.56          -        -     100.0
Ojos del Salado*.........    18.7     1.32          -       -     100.0       19.7     1.32          -        -     100.0
</TABLE>

- ---------------

 *  The Candelaria and Ojos del Salado deposits also contained, respectively,
    0.006 ounces and 0.008 ounces of gold per ton in 1998 and 1997.

**  Safford deposit includes Dos Pobres and San Juan reserves in 1998 and Dos
    Pobres reserves in 1997.
- --------------------------------------------------------------------------------

     Our estimated share of aggregate ore reserves at the above named properties
at December 31 is as follows:
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                              1998   1997   1996   1995   1994
                                                              ----   ----   ----   ----   ----
<S>                                                           <C>    <C>    <C>    <C>    <C>
Milling reserves (billion tons).............................  1.6    1.6    1.3    1.2     1.0
Leaching reserves (billion tons)............................  3.2    2.5    2.2    1.8     1.7
Commercially recoverable copper (million tons)..............  14.5   13.7   12.1   12.3   10.6
</TABLE>

- --------------------------------------------------------------------------------

     Ore reserves are those estimated quantities of ore that may be profitably
mined and processed for extraction of their constituent values. Estimates of our
reserves are based upon our engineering evaluations of assay values derived from
samplings of drill holes and other openings. In our opinion, the sites for such
samplings are spaced sufficiently close and the geologic characteristics of the
deposits are sufficiently well defined to render the estimates reliable. Stated
tonnages and grades of ore do not reflect waste dilution in mining or losses in
processing. Leaching reserves include copper estimated to be recoverable from
leach reserves remaining to be mined at Morenci, Chino, Tyrone, Cobre and
Safford. Commercially recoverable copper includes copper estimated to be
recoverable from milling and leaching reserves and from existing stockpiles of
leach material at Morenci, Chino, Tyrone, Cobre and Safford after taking into
consideration waste dilution and losses in processing.

                                       B-2
<PAGE>   102

     Ore reserves at each of our other mining operations and investments at
year-end 1998 are estimated as follows:
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                                ORE                              PHELPS
                                                              RESERVES                 %         DODGE
                                                              MILLION       %       CALCIUM     INTEREST
                                                                TONS      COPPER    FLUORIDE      (%)
                                                              --------    ------    --------    --------
<S>                                                           <C>         <C>       <C>         <C>
Southern Peru Copper Corporation*...........................  1.695.9      0.67       --          13.9
Phelps Dodge Mining Limited.................................     27.9      --        16.45       100.0
</TABLE>

- ---------------
* Southern Peru Copper Corporation deposits also contain approximately 790
  million tons of leach material at a grade of 0.22 percent copper.
- --------------------------------------------------------------------------------

     We hold various other properties containing mineral deposits that we
believe could be brought into production should market conditions warrant.
Permitting and significant capital expenditures would be required before
operations could commence at these properties. The deposits are estimated to
contain the following mineralized material as of December 31, 1998:
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                        SULFIDE MATERIAL        LEACH MATERIAL          PHELPS
                                                        ----------------   -------------------------    DODGE
                                                        MILLION     %      MILLION     %        %      INTEREST
                                            LOCATION     TONS     COPPER    TONS     COPPER   NICKEL     (%)
                                           ----------   -------   ------   -------   ------   ------   --------
<S>                                        <C>          <C>       <C>      <C>       <C>      <C>      <C>
American Mountain........................   Arizona      --        --         140     0.25     --        85.0
Cochise..................................   Arizona      --        --         210     0.40     --       100.0
Copper Basin.............................   Arizona        70      0.53      --       --       --       100.0
Garfield.................................   Arizona      --        --       1,000     0.27     --        85.0
Lone Star................................   Arizona      --        --       1,600     0.38     --       100.0
Sanchez..................................   Arizona      --        --         230     0.29     --       100.0
Western Copper...........................   Arizona       530      0.55       500     0.31     --        85.0
Piedras Verdes...........................    Mexico      --        --         310     0.37     --        70.0
Southern Peru Copper Corporation.........     Peru        370      0.62      --       --       --        13.9
Ambatovy*................................  Madagascar    --        --         210     --       1.10     100.0
</TABLE>

- ---------------
 * Ambatovy deposit also contains 0.10 percent cobalt.

** Mineralized deposit or mineralized material is a mineralized body which has
   been delineated by appropriately spaced drilling and/or underground sampling
   to support a sufficient tonnage and average grade of metal(s). Such a deposit
   does not qualify as a reserve, until comprehensive evaluation based upon unit
   cost, grade, recoveries, and other material factors conclude legal and
   economic feasibility.
- --------------------------------------------------------------------------------

                                       B-3
<PAGE>   103

     The letter of transmittal, certificates for Cyprus Amax shares and any
other required documents should be sent or delivered by each Cyprus Amax
shareholder or his or her broker, dealer, commercial bank, trust company or
other nominee to the Exchange Agent at one of its addresses set forth below.

                      The Exchange Agent for the Offer is:

                        CHASEMELLON SHAREHOLDER SERVICES

<TABLE>
<S>                             <C>                             <C>
           By Mail:                        By Hand:                 By Overnight Delivery:
   Reorganization Department       Reorganization Department       Reorganization Department
          PO Box 3301             120 Broadway, 13 (th) Floor         85 Challenger Road
  South Hackensack, NJ 07606          New York, NY 10271                Mail Stop-Reorg
                                                                   Ridgefield Park, NJ 07660
                                         By Facsimile:
                                  (for eligible institutions
                                             only)
                                      Fax: (201) 296-4293
</TABLE>

                      Confirm Facsimile by Telephone ONLY:
                                 (201) 296-4860

     Any questions or requests for assistance or additional copies of the
prospectus, the letter of transmittal and the notice of guaranteed delivery may
be directed to the Information Agent or the Dealer Manager at their respective
telephone numbers and locations listed below. You may also contact your local
broker, commercial bank, trust company or nominee for assistance concerning the
offer.

                    The Information Agent for the Offer is:
                           INNISFREE M&A INCORPORATED
                        501 Madison Avenue, 20(th) Floor
                               New York, NY 10022
                         CALL TOLL-FREE: 1-877-750-5838
                 Banks and Brokers Call Collect: (212) 750-5833

                      The Dealer Manager for the Offer is:
                           MORGAN STANLEY DEAN WITTER
                                 1585 Broadway
                               New York, NY 10036
                                 (212) 761-4000

<PAGE>   1

                             LETTER OF TRANSMITTAL

               TO EXCHANGE EACH OUTSTANDING SHARE OF COMMON STOCK
           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)
                                       OF

                          CYPRUS AMAX MINERALS COMPANY
                                      FOR

                         0.3135 SHARES OF COMMON STOCK
                                       OF

                            PHELPS DODGE CORPORATION

         THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT,

     NEW YORK CITY TIME, ON OCTOBER 1, 1999, UNLESS THE OFFER IS EXTENDED.


                      THE EXCHANGE AGENT FOR THE OFFER IS:


                    CHASEMELLON SHAREHOLDER SERVICES, L.L.C.



<TABLE>
<S>                                <C>                                <C>
             By Mail:                           By Hand:                    By Overnight Delivery:
                                                                          Reorganization Department
    Reorganization Department          Reorganization Department              85 Challenger Road
           PO Box 3301                 120 Broadway, 13(th) Floor              Mail Stop-Reorg
    South Hackensack, NJ 07606             New York, NY 10271             Ridgefield Park, NJ 07660
                                       By Facsimile Transmission:
                                    (for Eligible Institutions only)
                                          Fax: (201) 296-4293
                                         Confirm by Telephone:
                                             (201) 296-4860
</TABLE>


     DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET
FORTH ABOVE OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION OTHER
THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. YOU MUST SIGN THIS
LETTER OF TRANSMITTAL WHERE INDICATED BELOW AND COMPLETE THE SUBSTITUTE FORM W-9
PROVIDED BELOW.

     THE INSTRUCTIONS ACCOMPANYING THIS LETTER OF TRANSMITTAL SHOULD BE READ
CAREFULLY BEFORE THIS LETTER OF TRANSMITTAL IS COMPLETED.

     This Letter of Transmittal is to be completed by shareholders if
certificates for Cyprus Amax Shares (including the Cyprus Amax Rights) (as each
is defined herein) are to be forwarded herewith or, unless an Agent's Message is
utilized, if delivery of Cyprus Amax Shares are to be made by book-entry
transfer to the account maintained by the Exchange Agent at The Depository Trust
Company (the "Book-Entry Transfer Facility"), pursuant to the procedures set
forth under "The Offer -- Procedure for Tendering" in the Prospectus.
SHAREHOLDERS WILL BE REQUIRED TO TENDER ONE CYPRUS AMAX RIGHT FOR EACH CYPRUS
AMAX SHARE TENDERED IN ORDER TO EFFECT A VALID TENDER OF CYPRUS AMAX SHARES,
UNLESS THE RIGHTS PLAN CONDITION (AS DEFINED IN THE PROSPECTUS) HAS BEEN
SATISFIED OR WAIVED. UNLESS THE CYPRUS AMAX DISTRIBUTION DATE (AS DEFINED IN THE
PROSPECTUS) OCCURS, A TENDER OF CYPRUS AMAX SHARES WILL CONSTITUTE A TENDER OF
THE ASSOCIATED CYPRUS AMAX RIGHTS. Shareholders who tender Cyprus Amax Shares by
book-entry transfer are referred to herein as "Book-Entry Shareholders" and
other shareholders are referred to herein as "Certificate Shareholders."
Shareholders whose certificates are not immediately available or who cannot
deliver their certificates and all other documents required hereby to the
Exchange Agent on or prior to the Expiration Date (as defined in the
Prospectus), or who cannot comply with the book-entry transfer procedures on a
timely basis, may nevertheless tender their Cyprus Amax Shares according to the
guaranteed delivery procedures set forth under "The Offer -- Procedure for
Tendering" in the Prospectus. See Instruction 2. DELIVERY OF DOCUMENTS TO A
BOOK-ENTRY TRANSFER FACILITY DOES NOT CONSTITUTE DELIVERY TO THE EXCHANGE AGENT
FOR THIS OFFER (AS DEFINED HEREIN).
<PAGE>   2

[ ] CHECK HERE IF CYPRUS AMAX SHARES ARE BEING TENDERED PURSUANT TO A NOTICE OF
    GUARANTEED DELIVERY PREVIOUSLY SENT TO THE EXCHANGE AGENT AND COMPLETE THE
    FOLLOWING:

   Name(s) of Registered Holder(s)
   -----------------------------------------------------------------------------

   Date of Execution of Notice of Guaranteed Delivery
   ---------------------------------------------------------------------

   Name of Institution which Guaranteed Delivery
   --------------------------------------------------------------------------

[ ] CHECK HERE IF CYPRUS AMAX SHARES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER
    MADE TO THE ACCOUNT MAINTAINED BY THE EXCHANGE ACT WITH A BOOK-ENTRY
    TRANSFER FACILITY AND COMPLETE THE FOLLOWING:

   DTC Account Number
   -----------------------------------------------------------------------------

   Transaction Code Number
   -----------------------------------------------------------------------------


<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------------------------
                                       DESCRIPTION OF CYPRUS AMAX SHARES TENDERED
- ------------------------------------------------------------------------------------------------------------------------
      NAME(S) AND ADDRESS(ES) OF REGISTERED HOLDER(S)
             (PLEASE FILL IN EXACTLY AS NAME(S)                              CYPRUS AMAX SHARES TENDERED
                APPEAR(S) ON CERTIFICATE(S)                             (ATTACH ADDITIONAL LIST IF NECESSARY)
- ------------------------------------------------------------------------------------------------------------------------
                                                                                       SHARES            CYPRUS AMAX
                                                                 CERTIFICATE        EVIDENCED BY           SHARES
                                                                 NUMBER(S)*        CERTIFICATE(S)*       TENDERED**
<S>                                                          <C>                 <C>                 <C>
                                                             ------------------------------------------------------
                                                             ------------------------------------------------------
                                                             ------------------------------------------------------
                                                             ------------------------------------------------------
                                                             ------------------------------------------------------
                                                             Total Cyprus
                                                             Amax Shares
- ------------------------------------------------------------------------------------------------------------------------
  * Need not be completed by shareholders delivering by book-entry transfer.
 ** Unless otherwise indicated, it will be assumed that all Cyprus Amax Shares evidenced by a certificate(s) delivered
    to the Exchange Agent are being tendered. See Instruction 4.
- ------------------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>   3

                    NOTE: SIGNATURES MUST BE PROVIDED BELOW
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

Ladies and Gentlemen:


     The undersigned hereby delivers to CAV Corporation, a Delaware corporation,
and a wholly owned subsidiary of Phelps Dodge Corporation, a New York
corporation ("Phelps Dodge"), the above-described shares of common stock, no par
value (each, an "Cyprus Amax Share" and, collectively, the "Cyprus Amax
Shares"), of Cyprus Amax Minerals Company, a Delaware corporation ("Cyprus
Amax"), including the associated preferred share purchase rights (each, an
"Cyprus Amax Right" and, collectively, the "Cyprus Amax Rights") issued pursuant
to the Rights Agreement, dated as of February 28, 1999, as amended, between
Cyprus Amax and The Bank of New York, as Rights Agent, pursuant to Phelps
Dodge's offer to exchange 0.3135 shares of common stock, par value $6.25 per
share, of Phelps Dodge (the "Phelps Dodge Common Shares") for each outstanding
Cyprus Amax Share, upon the terms and subject to the conditions set forth in the
Prospectus dated September 2, 1999 (the "Prospectus"), receipt of which is
hereby acknowledged, and in this Letter of Transmittal (which together with the
Prospectus constitute the "Offer"). Unless the context otherwise requires and
unless and until the Cyprus Amax Rights are redeemed, all references to Cyprus
Amax Shares shall include the associated Cyprus Amax Rights.



     Upon the terms and subject to the conditions of the Offer, subject to, and
effective upon, acceptance of the Cyprus Amax Shares tendered herewith in
accordance with the terms of the Offer, the undersigned hereby sells, assigns
and transfers to, or upon the order of, Phelps Dodge, all right, title and
interest in and to all of the Cyprus Amax Shares that are being tendered hereby
and any and all Cyprus Amax Shares and other securities issued or issuable in
respect thereof on or after September 2, 1999 (collectively, "Distributions"),
and appoints the Exchange Agent the true and lawful agent and attorney-in-fact
of the undersigned with respect to such Cyprus Amax Shares (and any
Distributions), (such power of attorney being deemed to be an irrevocable power
coupled with an interest), to (a) deliver such Cyprus Amax Share Certificates
(as defined herein) (and any Distributions) or transfer ownership of such Cyprus
Amax Shares (and any Distributions) on the account books maintained by a
Book-Entry Transfer Facility, together in either such case with all accompanying
evidences of transfer and authenticity, to or upon the order of Phelps Dodge,
(b) present such Cyprus Amax Shares (and any Distributions) for transfer on the
books of Cyprus Amax and (c) receive all benefits and otherwise exercise all
rights of beneficial ownership of such Cyprus Amax Shares (and any
Distributions), all in accordance with the terms and the conditions of the
Offer.


     THE UNDERSIGNED UNDERSTANDS THAT STOCKHOLDERS WILL BE REQUIRED TO TENDER
ONE CYPRUS AMAX RIGHT FOR EACH CYPRUS AMAX SHARE TENDERED IN ORDER TO EFFECT A
VALID TENDER OF CYPRUS AMAX SHARES, UNLESS THE RIGHTS PLAN CONDITION (AS DEFINED
IN THE PROSPECTUS) HAS BEEN SATISFIED OR WAIVED. UNLESS THE CYPRUS AMAX
DISTRIBUTION DATE (AS DEFINED IN THE PROSPECTUS) OCCURS, A TENDER OF CYPRUS AMAX
SHARES WILL CONSTITUTE A TENDER OF THE ASSOCIATED CYPRUS AMAX RIGHTS. SEE
INSTRUCTION 10.


     The undersigned hereby irrevocably appoints the designees of Phelps Dodge,
and each of them, the attorneys-in-fact and proxies of the undersigned, each
with full power of substitution, to vote in such manner as each such attorney
and proxy or any substitute thereof shall deem proper in the sole discretion of
such attorney-in-fact and proxy or such substitute, and otherwise act (including
pursuant to written consent) with respect to all of the Cyprus Amax Shares
tendered hereby (and any Distributions) which have been accepted by Phelps Dodge
prior to the time of such vote or action, which the undersigned is entitled to
vote at any meeting of shareholders (whether annual or special and whether or
not an adjourned meeting), of Cyprus Amax or otherwise. This proxy and power of
attorney is coupled with an interest in the Cyprus Amax Shares and is
irrevocable and is granted in consideration of, and is effective upon, the
acceptance of such Cyprus Amax Shares (and any Distributions) by Phelps Dodge in
accordance with the terms of the Offer. Such acceptance for exchange shall
revoke any other proxy granted by the undersigned at any time with respect to
such Cyprus Amax Shares (and any Distributions) and no subsequent proxies will
be given (or, if given, will not be deemed effective) with respect thereto by
the undersigned. The undersigned understands that, in order for Cyprus Amax
Shares to be deemed validly tendered immediately upon Phelps Dodge's acceptance
of such Cyprus Amax Shares (and any Distributions) for exchange, Phelps Dodge or
its designee must be able to exercise full voting rights with respect to such
Cyprus Amax Shares (and any Distributions).

<PAGE>   4

     The undersigned hereby represents and warrants that the undersigned has
full power and authority to tender, sell, assign and transfer the Cyprus Amax
Shares (and any Distributions) tendered hereby and that when the same are
accepted for exchange by Phelps Dodge, Phelps Dodge will acquire good,
marketable and unencumbered title thereto, free and clear of all liens,
restrictions, charges and encumbrances, and the same will not be subject to any
adverse claim. The undersigned will, upon request, execute and deliver any
additional documents deemed by the Exchange Agent or Phelps Dodge to be
necessary or desirable to complete the sale, assignment and transfer of the
Cyprus Amax Shares (and any Distributions) tendered hereby. In addition, the
undersigned shall promptly remit and transfer to the Exchange Agent for the
account of Phelps Dodge any and all Distributions in respect of the Cyprus Amax
Shares tendered hereby, accompanied by appropriate documentation of transfer.

     All authority herein conferred or agreed to be conferred shall not be
affected by and shall survive the death or incapacity of the undersigned, and
any obligation of the undersigned hereunder shall be binding upon the heirs,
personal representatives, successor and assigns of the undersigned. Subject to
the withdrawal rights set forth under "The Offer -- Withdrawal Rights" in the
Prospectus, the tender of Cyprus Amax Shares hereby made is irrevocable.

     The undersigned understands that tenders of Cyprus Amax Shares pursuant to
any one of the procedures described under "The Offer -- Procedure for Tendering"
in the Prospectus and in the instructions hereto and acceptance of such Cyprus
Amax Shares will constitute a binding agreement between the undersigned and
Phelps Dodge upon the terms and subject to the conditions set forth in the
Offer.


     Unless otherwise indicated herein under "Special Issuance Instructions,"
please issue the shares of Phelps Dodge Common Shares and/or return any
certificates for Cyprus Amax Shares not tendered or not accepted for exchange in
the name(s) of the registered holder(s) appearing under "Description of Cyprus
Amax Shares Tendered." Similarly, unless otherwise indicated under "Special
Delivery Instructions," please mail the Phelps Dodge Common Shares and cash in
lieu of fractional Phelps Dodge Common Shares and/or return any certificates for
Cyprus Amax Shares not tendered or not accepted for exchange (and accompanying
documents, as appropriate) to the address(es) of the registered holder(s)
appearing under "Description of Cyprus Amax Shares Tendered." In the event that
both the Special Delivery Instructions and the Special Issuance Instructions are
completed, please issue the Phelps Dodge Common Shares and/or issue any
certificates for Cyprus Amax Shares not so tendered or accepted in the name of,
and deliver said certificates and/or return such certificates to, the person or
persons so indicated. The undersigned recognizes that Phelps Dodge has no
obligation to transfer any Cyprus Amax Shares from the name of the registered
holder thereof if Phelps Dodge does not accept any of the Cyprus Amax Shares so
tendered.

<PAGE>   5

          ------------------------------------------------------------

                         SPECIAL ISSUANCE INSTRUCTIONS
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)


        To be completed ONLY if certificate(s) for Cyprus Amax Shares not
   tendered or not accepted and/or the Phelps Dodge Common Shares are to be
   issued in the name of someone other than the undersigned.



   Issue Phelps Dodge Common Shares and/or or certificate(s) to:


   Name
   ----------------------------------------------------
                                (PLEASE TYPE OR PRINT)

   Address
   --------------------------------------------------

          ------------------------------------------------------------
                               (INCLUDE ZIP CODE)

          ------------------------------------------------------------
                  (TAX IDENTIFICATION OR SOCIAL SECURITY NO.)
                   (SEE SUBSTITUTE FORM W-9 ON REVERSE SIDE)

          ------------------------------------------------------------
          ------------------------------------------------------------

                         SPECIAL DELIVERY INSTRUCTIONS
                         (SEE INSTRUCTIONS 1, 6 AND 7)


        To be completed ONLY if certificate(s) for Cyprus Amax Shares not
   tendered or not accepted and/or the Phelps Dodge Common Shares are to be
   sent to someone other than the undersigned, or to the undersigned at an
   address other than that shown above.



   Mail Phelps Dodge Common Shares and/or certificate(s) to:


   Name
   ----------------------------------------------------
                                (PLEASE TYPE OR PRINT)

   Address
   --------------------------------------------------

          ------------------------------------------------------------
                               (INCLUDE ZIP CODE)

          ------------------------------------------------------------
                  (TAX IDENTIFICATION OR SOCIAL SECURITY NO.)
                   (SEE SUBSTITUTE FORM W-9 ON REVERSE SIDE)

          ------------------------------------------------------------
<PAGE>   6

                                   IMPORTANT
                             SHAREHOLDERS SIGN HERE
             (PLEASE COMPLETE SUBSTITUTE FORM W-9 ON REVERSE SIDE)

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
                         SIGNATURE(S) OF STOCKHOLDER(S)

Dated:
- --------------------------- , 1999

(Must be signed by registered holder(s) exactly as name(s) appear(s) on stock
certificate(s) or on a security position listing or by person(s) authorized to
become registered holder(s) by certificate(s) and documents transmitted
herewith. If signature is by trustees, executors, administrators, guardians,
attorneys-in-fact, officers of corporations or others acting in a fiduciary or
representative capacity, please set forth full title and see Instruction 5.)

Name(s):------------------------------------------------------------------------
                                 (PLEASE PRINT)

Capacity (Full Title)
                ----------------------------------------------------------------

Address:
       -------------------------------------------------------------------------

- --------------------------------------------------------------------------------
                               (INCLUDE ZIP CODE)
Area Code and Telephone Number:
                           -----------------------------------------------------


Tax Identification or Social Security No.:

- ---------------------------------------------------------------------------
<PAGE>   7

                           GUARANTEE OF SIGNATURE(S)
                           SEE INSTRUCTIONS 1 AND 5)
                     FOR USE BY ELIGIBLE INSTITUTIONS ONLY,
                    PLACE MEDALLION GUARANTEE IN SPACE BELOW
Authorized Signature:
                ----------------------------------------------------------------

Name: --------------------------------------------------------------------------
                             (PLEASE TYPE OR PRINT)

Address:
       -------------------------------------------------------------------------
                               (INCLUDE ZIP CODE)

Name of Firm:
           ---------------------------------------------------------------------

Area Code and Telephone Number:
                           -----------------------------------------------------

Dated:
- --------------------------- , 1999
<PAGE>   8

                                  INSTRUCTIONS
             FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER

     1.  GUARANTEE OF SIGNATURES.  Except as otherwise provided below, all
signatures on this Letter of Transmittal must be guaranteed by a financial
institution (including most banks, savings and loan associations and brokerage
houses) which is a participant in the Securities Transfer Agents Medallion
Program, the New York Stock Exchange Medallion Signature Program or the Stock
Exchange Medallion Program (an "Eligible Institution"). Signatures on this
Letter of Transmittal need not be guaranteed (i) if this Letter of Transmittal
is signed by the registered holder(s) of the Cyprus Amax Shares (which term, for
purposes of this document, shall include any participant in the Book-Entry
Transfer Facility whose name appears on a security position listing as the owner
of Cyprus Amax Shares) tendered herewith and such holder(s) have not completed
the instruction entitled "Special Issuance Instructions" on this Letter of
Transmittal or (ii) if such Cyprus Amax Shares are tendered for the account of
an Eligible Institution. See Instruction 5.

     2.  DELIVERY OF LETTER OF TRANSMITTAL AND CERTIFICATES OR BOOK-ENTRY
CONFIRMATIONS.  This Letter of Transmittal is to be used either if certificates
are to be forwarded herewith or, unless an Agent's Message is utilized, if
tenders are to be made pursuant to the procedures for tender by book-entry
transfer set forth in "The Offer -- Procedure for Tendering" in the Prospectus.
Certificates for all physically tendered Cyprus Amax Shares ("Cyprus Amax Share
Certificates"), or confirmation of any book-entry transfer into the Exchange
Agent's account at the Book-Entry Transfer Facility ("Book-Entry Confirmation")
of Cyprus Amax Shares tendered by book-entry transfer, as well as this Letter of
Transmittal or facsimile thereof, properly completed and duly executed with any
required signature guarantees, and any other documents required by this Letter
of Transmittal, must be received by the Exchange Agent at one of its addresses
set forth herein on or prior to the Expiration Date (as defined in the
Prospectus).

     Shareholders whose certificates are not immediately available or who cannot
deliver their certificates and all other required documents to the Exchange
Agent on or prior to the Expiration Date or who cannot complete the procedures
for book-entry transfer on a timely basis may nevertheless tender their Cyprus
Amax Shares by properly completing and duly executing a Notice of Guaranteed
Delivery pursuant to the guaranteed delivery procedures set forth under "The
Offer -- Procedure for Tendering" in the Prospectus. Pursuant to such
procedures: (i) such tender must be made by or through an Eligible Institution;
(ii) a properly completed and duly executed Notice of Guaranteed Delivery
substantially in the form made available by Phelps Dodge must be received by the
Exchange Agent on or prior to the Expiration Date; and (iii) the Cyprus Amax
Share Certificates for all tendered Cyprus Amax Shares (or a confirmation of a
book-entry transfer of such securities into the Exchange Agent's account at the
Book-Entry Transfer Facility of Cyprus Amax Shares tendered by book-entry
transfer), in proper form for transfer, together with a properly completed and
duly executed Letter of Transmittal (or facsimile thereof) with any required
signature guarantees (or, in the case of a book-entry delivery, an Agent's
Message) and all other documents required by this Letter of Transmittal, must be
received by the Exchange Agent within three New York Stock Exchange, Inc.
trading days after the date of execution of such Notice of Guaranteed Delivery.

     IF CYPRUS AMAX SHARE CERTIFICATES ARE FORWARDED SEPARATELY TO THE EXCHANGE
AGENT, A PROPERLY COMPLETED AND DULY EXECUTED LETTER OF TRANSMITTAL MUST
ACCOMPANY EACH SUCH DELIVERY.

     THE METHOD OF DELIVERY OF CYPRUS AMAX SHARE CERTIFICATES AND ALL OTHER
REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH THE BOOK-ENTRY TRANSFER FACILITY,
IS AT THE OPTION AND RISK OF THE TENDERING SHAREHOLDER, AND DELIVERY WILL BE
DEEMED MADE ONLY WHEN ACTUALLY RECEIVED BY THE EXCHANGE AGENT. IF DELIVERY IS BY
MAIL, REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS
RECOMMENDED. IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY
DELIVERY.

     No alternative, condition or contingent tenders will be accepted and no
fractional Cyprus Amax Shares will be accepted. All tendering shareholders, by
execution of this Letter of Transmittal (or facsimile thereof), waive any right
to receive any notice of the acceptance of their Cyprus Amax Shares for
exchange.

     3.  INADEQUATE SPACE.  If the space provided herein is inadequate, the
certificate numbers and/or the number of Cyprus Amax Shares should be listed on
a separate schedule attached hereto.
<PAGE>   9

     4.  PARTIAL TENDERS (NOT APPLICABLE TO STOCKHOLDERS WHO TENDER BY
BOOK-ENTRY TRANSFER).  If fewer than all the Cyprus Amax Shares evidenced by any
certificate submitted are to be tendered, fill in the number of Cyprus Amax
Shares which are to be tendered in the box entitled "Number of Cyprus Amax
Shares Tendered." In such cases, new certificate(s) for the remainder of the
Cyprus Amax Shares that were evidenced by your old certificate(s) will be sent
to you, unless otherwise provided in the appropriate box on this Letter of
Transmittal, as soon as practicable after the Expiration Date. All Cyprus Amax
Shares represented by certificates delivered to the Exchange Agent will be
deemed to have been tendered unless otherwise indicated.

     5.  SIGNATURES ON LETTER OF TRANSMITTAL; STOCK POWERS AND ENDORSEMENTS.  If
this Letter of Transmittal is signed by the registered holder(s) of the Cyprus
Amax Shares tendered hereby, the signature(s) must correspond with the name(s)
as written on the face of the certificates without alteration, enlargement or
any change whatsoever.

     If any of the Cyprus Amax Shares tendered hereby are owned of record by two
or more joint owners, all such owners must sign this Letter of Transmittal.

     If any of the tendered Cyprus Amax Shares are registered in different names
on several certificates, it will be necessary to complete, sign and submit as
many separate Letters of Transmittal as there are different registrations of
certificates.

     If this Letter of Transmittal or any certificates or stock powers are
signed by trustees, executors, administrators, attorneys-in-fact, officers of
corporations or others acting in a fiduciary or representative capacity, such
persons should so indicate when signing, and proper evidence satisfactory to
Phelps Dodge of their authority so to act must be submitted.

     If this Letter of Transmittal is signed by the registered holder(s) of the
Cyprus Amax Shares listed and transmitted hereby, no endorsements of
certificates or separate stock powers are required unless Phelps Dodge Common
Share or certificates for Cyprus Amax Shares not tendered or accepted are to be
issued in the name of a person other than the registered holder(s). Signatures
on such certificates or stock powers must be guaranteed by an Eligible
Institution.

     If this Letter of Transmittal is signed by a person other than the
registered holder of the certificate(s) listed, the certificate(s) must be
endorsed or accompanied by appropriate stock powers, in either case signed
exactly as the name or names of the registered holder or holders appear on the
certificate(s). Signatures on such certificates or stock powers must be
guaranteed by an Eligible Institution.

     6.  STOCK TRANSFER TAXES.  Phelps Dodge will pay or cause to be paid any
stock transfer taxes with respect to the transfer and sale of Cyprus Amax Shares
to it or its order pursuant to the Offer. If, however, delivery of the
consideration in respect of the Offer is to be made to, or (in the circumstances
permitted hereby) if certificates for Cyprus Amax Shares not tendered or
accepted are to be registered in the name of, any person other than the
registered holder, or if tendered certificates are registered in the name of any
person other than the person(s) signing this Letter of Transmittal, the
tendering holder must provide satisfactory evidence of the payment of any
applicable transfer taxes (whether imposed on the registered holder or such
person) payable on account of the transfer to such person prior to the delivery
of the consideration pursuant to the Offer. Except as provided in this
Instruction 6, it will not be necessary for transfer tax stamps to be affixed to
the certificates listed in this Letter of Transmittal.


     7.  SPECIAL ISSUANCE AND DELIVERY INSTRUCTIONS.  If certificates for Phelps
Dodge Common Shares and/or certificates for Cyprus Amax Shares not tendered or
not accepted for exchange are to be issued in the name of a person other than
the person(s) signing this Letter of Transmittal or if certificates for Phelps
Dodge Common Shares and cash in lieu of fractional Phelps Dodge Common Shares
and/or certificates for Cyprus Amax Shares not tendered or not accepted for
exchange are to be mailed to someone other than the person(s) signing this
Letter of Transmittal or to an address other than that shown above, the
appropriate boxes on this Letter of Transmittal should be completed.
Shareholders tendering Cyprus Amax Shares by book-entry transfer may request
that Cyprus Amax Shares not accepted pursuant to the Offer be credited to such
account maintained at a Book-Entry Transfer Facility as such stockholder may
designate hereon. If no such instructions are given, such Cyprus Amax Shares not
accepted will be returned by crediting the account at the Book-Entry Transfer
Facility designated herein.

<PAGE>   10

     8.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Questions or requests
for assistance may be directed to, or additional copies of the Prospectus, this
Letter of Transmittal, the Notice of Guaranteed Delivery and other tender offer
materials may be obtained from, the Information Agent or the Dealer Manager at
their respective addresses set forth below or from your broker, dealer,
commercial bank or trust company.

     9.  SUBSTITUTE FORM W-9.  Each tendering shareholder is required to provide
the Exchange Agent with a correct Taxpayer Identification Number ("TIN"),
generally the stockholder's social security or federal employer identification
number, on Substitute Form W-9 below. In addition, payments of cash in lieu of
fractional shares of Phelps Dodge Common Shares that are made to such
shareholder with respect to Cyprus Amax Shares accepted pursuant to the Offer
may be subject to backup withholding of 31%. The box in Part 3 of the form may
be checked if the tendering shareholder has not been issued a TIN and has
applied for a number or intends to apply for a number in the near future. If the
box in Part 3 is checked and the Exchange Agent is not provided with a TIN
within 60 days, the Exchange Agent must withhold 31% of all payments of cash
thereafter until a TIN is provided to the Exchange Agent. In addition, the
Exchange Agent may backup withhold during the 60 day period under certain
circumstances. The shareholder is required to give the Exchange Agent the social
security number or employer identification number of the record owner of the
Cyprus Amax Shares or of the last transferee appearing on the stock powers
attached to, or endorsed on, the Cyprus Amax Shares. If the Cyprus Amax Shares
are in more than one name or are not in the name of the actual owner, consult
the enclosed Guidelines for Certification of Taxpayer Identification Number on
Substitute Form W-9 for additional guidance on which number to report.

     10.  TENDER OF CYPRUS AMAX RIGHTS AFTER CYPRUS AMAX'S DISTRIBUTION
DATE.  If the Cyprus Amax Distribution Date occurs and separate certificates
representing the Cyprus Amax Rights are distributed by Cyprus Amax or the Rights
Agent to holders of Cyprus Amax Shares prior to the time a holder's Cyprus Amax
Shares are tendered pursuant to the Offer, certificates representing a number of
Cyprus Amax Rights equal to the number of Cyprus Amax Shares tendered must be
delivered to the Exchange Agent, or, if available, a Book-Entry Confirmation
received by the Exchange Agent with respect thereto, in order for such Cyprus
Amax Shares to be validly tendered. If the Cyprus Amax Distribution Date occurs
and separate certificates representing the Cyprus Amax Rights are not
distributed prior to the time Cyprus Amax Shares are tendered pursuant to the
Offer, Cyprus Amax Rights may be tendered prior to a stockholder receiving the
certificates for Cyprus Amax Rights by use of the guaranteed delivery procedures
described under "The Offer -- Procedure for Tendering" in the Prospectus. If
Cyprus Amax Rights certificates are distributed but are not available to a
shareholder prior to the time Cyprus Amax Shares are tendered pursuant to the
Offer, a tender of Cyprus Amax Shares constitutes an agreement by the tendering
shareholder to deliver to the Exchange Agent pursuant to such guaranteed
delivery procedures, prior to the expiration of the period to be specified in
the Notice of Guaranteed Delivery and the related Letter of Transmittal for
delivery of Cyprus Amax Rights certificates or a Book-Entry Confirmation for
Cyprus Amax Rights (the "Cyprus Amax Rights Delivery Period"), Cyprus Amax
Rights certificates representing a number of Cyprus Amax Rights equal to the
number of Cyprus Amax Shares tendered. Phelps Dodge reserves the right to
require that it receive such Cyprus Amax Rights certificates (or a Book-Entry
Confirmation with respect to such Cyprus Amax Rights) prior to accepting Cyprus
Amax Shares for exchange.

     Nevertheless, Phelps Dodge will be entitled to accept for exchange Cyprus
Amax Shares tendered by a stockholder prior to receipt of the Cyprus Amax Rights
certificates required to be tendered with such Cyprus Amax Shares or a Book-
Entry Confirmation with respect to such Cyprus Amax Rights and either (i)
subject to complying with applicable rules and regulations of the Securities and
Exchange Commission, withhold payment for such Cyprus Amax Shares pending
receipt of the Cyprus Amax Rights certificates or a Book-Entry Confirmation for
such Cyprus Amax Rights or (ii) exchange Cyprus Amax Shares accepted for
exchange pending receipt of the Cyprus Amax Rights certificates or a Book-Entry
Confirmation for such Cyprus Amax Rights in reliance upon the guaranteed
delivery procedures. In addition, after expiration of the Cyprus Amax Rights
Delivery Period, Phelps Dodge may instead elect to reject as invalid a tender of
Cyprus Amax Shares with respect to which Cyprus Amax Rights certificates or a
Book-Entry Confirmation for an equal number of Cyprus Amax Rights have not been
received by the Exchange Agent. Any determination by Phelps Dodge to make
payment for Cyprus Amax Shares in reliance upon such guaranteed delivery
procedure or, after expiration of the Cyprus Amax Rights Delivery Period, to
reject a tender as invalid, shall be made, subject to applicable law, in the
sole and absolute discretion of Phelps Dodge.
<PAGE>   11


     11.  LOST OR DESTROYED CERTIFICATES.  If any Cyprus Amax Share
certificate(s) representing Cyprus Amax Shares has been lost or destroyed, the
holders should promptly notify Cyprus Amax's Transfer Agent. The holders will
then be instructed as to the procedure to be followed in order to replace the
Cyprus Amax Share certificates. This Letter of Transmittal and related documents
cannot be processed until the procedures for replacing lost or destroyed Cyprus
Amax Share certificates have been followed.


     IMPORTANT:  THIS LETTER OF TRANSMITTAL OR A FACSIMILE COPY HEREOF (TOGETHER
WITH CYPRUS AMAX SHARE CERTIFICATES OR CONFIRMATION OF BOOK-ENTRY TRANSFER AND
ALL OTHER REQUIRED DOCUMENTS) OR THE NOTICE OF GUARANTEED DELIVERY MUST BE
RECEIVED BY THE EXCHANGE AGENT ON OR PRIOR TO THE EXPIRATION DATE.

                           IMPORTANT TAX INFORMATION

     Certain shareholders (including, among others, corporations and certain
foreign individuals) are not subject to backup withholding. In order for a
foreign individual to qualify as an exempt recipient, that stockholder must
submit a Form W-8 or successor form, signed under penalties of perjury,
attesting to that individual's exempt status. A Form W-8 can be obtained from
the Exchange Agent. See the enclosed Guidelines for Certificate of Taxpayer
Identification Number on Substitute Form W-9 for additional instructions.

     Backup withholding is not an additional tax. Rather, the tax liability of
person subject to backup withholding will be reduced by the amount of tax
withheld. If withholding results in an overpayment of taxes, a refund may be
obtained from the Internal Revenue Service.
<PAGE>   12

                 TO BE COMPLETED BY ALL TENDERING SHAREHOLDERS
                              (SEE INSTRUCTION 9)


- --------------------------------------------------------------------------------

<TABLE>
<S>                             <C>                                                         <C>

  PAYER'S NAME: CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
- ------------------------------------------------------------------------------------------------------------------------------


  SUBSTITUTE                      PART 1 -- PLEASE PROVIDE YOUR TIN IN THE BOX AT RIGHT         --------------------------
  FORMW-9                         AND CERTIFY BY SIGNING AND DATED BELOW.                       SOCIAL SECURITY NUMBER(S)
                                                                                                            OR
                                                                                              ------------------------------
                                                                                            EMPLOYER IDENTIFICATION NUMBER(S)
                                ----------------------------------------------------------------------------------------------
 DEPARTMENT OF
  THE TREASURY                    PART 2 -- CERTIFICATION -- UNDER PENALTIES OF PERJURY, I                PART 3
  INTERNAL REVENUE                CERTIFY THAT:
  SERVICE                                                                                           AWAITING TIN  [ ]
  PAYER'S REQUEST FOR TAXPAYER    (1) The number shown on this form is my correct Taxpayer
  IDENTIFICATION                      Identification Number (or I am waiting for a number
  NUMBER ("TIN")                      to be issued to me); and
                                  (2) I am not subject to backup withholding either
                                      because (i) I am exempt from backup withholding,
                                      (ii) I have not been notified by the Internal Reve-
                                      nue Service (the "IRS") that I am subject to backup
                                      withholding as a result of a failure to report all
                                      interest or dividends, or (iii) the IRS has noti-
                                      fied me that I am no longer subject to backup
                                      withholding.
- ------------------------------------------------------------------------------------------------------------------------------
   Certificate Instructions -- You must cross out item (2) in Part 2 if you have been notified by the IRS that you are
   currently subject to backup withholding because of under-reporting interest or dividends on your tax return. However, if
   after being notified by the IRS that you were subject to backup withholding you received another notification from the IRS
   stating that you are no longer subject to backup withholding, do not cross out item (2).

- ------------------------------------------------------------------------------------------------------------------------------
   SIGNATURE: --------------------------------------------------  DATE: --------------
   NAME (PLEASE PRINT): ------------------------------------------------------------
   ADDRESS: ------------------------------------------------------------------------
   CITY, STATE AND ZIP CODE: -------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------------
</TABLE>


NOTE:  FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN A PENALTY IMPOSED
       BY THE INTERNAL INCOME SERVICE AND IN BACKUP WITHHOLDING OF 31% OF ANY
       PAYMENTS MADE TO YOU PURSUANT TO THE OFFER. PLEASE REVIEW THE ENCLOSED
       GUIDELINES FOR CERTIFICATIONS OF TAXPAYER IDENTIFICATION NUMBER ON
       SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.

           YOU MUST COMPLETE THE FOLLOWING CERTIFICATE IF YOU CHECKED
                    THE BOX IN PART 3 OF SUBSTITUTE FORM W-9
<PAGE>   13

             CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER

     I certify under penalties of perjury that a Taxpayer Identification Number
has not been issued to me, and either (i) I have mailed or delivered an
application to receive a Taxpayer Identification Number to the appropriate
Internal Revenue Service Center or Social Security Administration Office or (ii)
I intend to mail or deliver an application in the near future. I understand that
if I do not provide a Taxpayer Identification Number within 60 days, 31% of all
reportable payments made to me thereafter will be withheld until I provide a
Taxpayer Identification Number.

<TABLE>
<S>                                                             <C>
- ------------------------------------------------------------    ---------------------------------
                         Signature                                            Date
Name (Please Print):
- ------------------------------------------------------------
</TABLE>

                    The Information Agent for this Offer is:

                           Innisfree M&A Incorporated
                         501 Madison Avenue, 20th Floor
                            New York, New York 10022

                        Bankers and Brokers Call Collect
                                 (212)-750-5833

                           All Others Call Toll Free
                                 1-877-750-5838

                      The Dealer Manager for the Offer is:


                       MORGAN STANLEY & CO. INCORPORATED

                                 1585 Broadway
                               New York, NY 10036
                                 (212) 761-4000

<PAGE>   1

                         NOTICE OF GUARANTEED DELIVERY

                                 FOR TENDER OF
                             SHARES OF COMMON STOCK

           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)


                                       OF

                          CYPRUS AMAX MINERALS COMPANY

                                       TO

                            PHELPS DODGE CORPORATION

                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)


     As set forth under "The Offer -- Procedure for Tendering" in the
Prospectus, dated September 2, 1999 (the "Prospectus"), this form or one
substantially equivalent hereto must be used to accept the Offer (as defined
herein) if certificates for shares of common stock, no par value (each, a
"Cyprus Amax Share" and, collectively, the "Cyprus Amax Shares"), of Cyprus Amax
Minerals Company, a Delaware corporation ("Cyprus Amax"), including the
associated preferred share purchase rights (each, an "Cyprus Amax Right" and,
collectively, the "Cyprus Amax Rights") issued pursuant to the Cyprus Amax
Rights Agreement, dated as of February 28, 1999, as amended, between Cyprus Amax
and The Bank of New York, as Rights Agent, are not immediately available, if the
certificates and all other required documents cannot be delivered to the
Exchange Agent prior to the Expiration Date (as defined in the Prospectus), or
if the procedure for book-entry transfer cannot be completed on a timely basis.
Such form may be delivered by hand or transmitted by telegram, facsimile
transmission or mail to the Exchange Agent, and must include a guarantee by an
Eligible Institution (as defined in the Prospectus). See "The Offer -- Procedure
for Tendering" in the Prospectus.


                      The Exchange Agent for the Offer is:


                    CHASEMELLON SHAREHOLDER SERVICES, L.L.C.



<TABLE>
<S>                             <C>                             <C>
           By Mail:                        By Hand:                 By Overnight Delivery:
   Reorganization Department       Reorganization Department       Reorganization Department
          PO Box 3301             120 Broadway, 13(th) Floor          85 Challenger Road
  South Hackensack, NJ 07606          New York, NY 10271                Mail Stop-Reorg
                                                                   Ridgefield Park, NJ 07660
</TABLE>



                           By Facsimile Transmission:



                        (for Eligible Institutions only)


                              Fax: (201) 296-4293



                             Confirm by Telephone:


                                 (201) 296-4860


     DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS
SET FORTH ABOVE OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION OTHER
THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.
<PAGE>   2

     This form is not to be used to guarantee signatures. If a signature on a
Letter of Transmittal is required to be guaranteed by an Eligible Institution
under the instructions thereto, such signature guarantee must appear in the
applicable space provided in the signature box on the Letter of Transmittal.

LADIES AND GENTLEMEN:


     The undersigned hereby tenders to CAV Corporation, a Delaware corporation,
and a wholly owned subsidiary of Phelps Dodge Corporation upon the terms and
subject to the conditions set forth in the Prospectus dated September 2, 1999
and in the related Letter of Transmittal (which together constitute the
"Offer"), receipt of which is hereby acknowledged, the number of Cyprus Amax
Shares shown below pursuant to the guaranteed delivery procedures set forth
under "The Offer -- Procedure for Tendering" in the Prospectus.


             ------------------------------------------------------

   Number of Cyprus Amax Shares:

   ------------------------------------------------------

   Account
   Number:
   --------------------------------------------

   Certificate No(s). (if available):

             ------------------------------------------------------

             ------------------------------------------------------

   If Cyprus Amax Share(s) will be tendered by book-entry transfer:

   ------------------------------------------------------

   Name of Tendering Institution:

   ------------------------------------------------------

   Account
   Number:
   --------------------------------------------

   at The Depository Trust Company

   Date:
   ------------------------------------------------
- ------------------------------------------------------
             ------------------------------------------------------

   Name(s) of Record Holder(s):

   ------------------------------------------------------

   ------------------------------------------------------

   Address(es):

   ------------------------------------------------------

   ------------------------------------------------------

   Area Code and Telephone Number(s):

   ------------------------------------------------------

   Signature(s):

   ------------------------------------------------------

   ------------------------------------------------------

   ------------------------------------------------------

   ------------------------------------------------------

   ------------------------------------------------------
- ------------------------------------------------------
<PAGE>   3

                     THE GUARANTEE BELOW MUST BE COMPLETED

                                   GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)

     The undersigned, a financial institution that is a participant in the
Securities Transfer Agents Medallion Program, the New York Stock Exchange
Medallion Signature Program or the Stock Exchange Medallion Program, guarantees
(a) that the above-named person(s) "own(s)" the Cyprus Amax Shares tendered
hereby within the meaning of Rule 14e-4 under the Securities Exchange Act of
1934, as amended, (b) represents that such tender complies with Rule 14e-4 and
(c) guarantees to deliver to the Exchange Agent, at one of its addresses set
forth above, certificates representing the Cyprus Amax Shares tendered hereby,
in proper form for transfer, or confirmation of book-entry transfer of such
Cyprus Amax Shares into the Exchange Agent's accounts at The Depository Trust
Company, in each case with delivery of a properly completed and duly executed
Letter of Transmittal (or a facsimile copy thereof), or an Agent's Message (as
defined in the Prospectus) in the case of book-entry transfer, and any other
documents required by the Letter of Transmittal, within three New York Stock
Exchange, Inc. trading days of the date hereof.

<TABLE>
<S>                                              <C>
Name of Firm:
  --------------------------------------
                                                 ---------------------------------------------
                                                 AUTHORIZED SIGNATURE
Address:                                         Title:
- ---------------------------------------------    ---------------------------------------------
                                                 Name:
- ---------------------------------------------    ---------------------------------------------
Zip Code                                                     Please Print or Type
Area Code and
Telephone Number:
  ---------------------------------              Dated: --------- , 1999
</TABLE>

    NOTE: DO NOT SEND CERTIFICATES FOR CYPRUS AMAX SHARES WITH THIS NOTICE.
            CYPRUS AMAX SHARE CERTIFICATES SHOULD BE SENT WITH YOUR
                             LETTER OF TRANSMITTAL.

<PAGE>   1


                       MORGAN STANLEY & CO. INCORPORATED


                                 1585 BROADWAY
                            NEW YORK, NEW YORK 10036

            OFFER TO EXCHANGE EACH OUTSTANDING SHARE OF COMMON STOCK
           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)

                                       OF

                          CYPRUS AMAX MINERALS COMPANY

                                      FOR

                         0.3135 SHARES OF COMMON STOCK

                                       OF

                            PHELPS DODGE CORPORATION

  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
 TIME, ON             , 1999, UNLESS THE OFFER IS EXTENDED. ASARCO SHARES THAT
  ARE TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE
                            EXPIRATION OF THE OFFER.


                                                               September 3, 1999


To Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees:


     We have been appointed by Phelps Dodge Corporation, a New York corporation
("Phelps Dodge"), to act as Dealer Manager in connection with Phelps Dodge's
offer to exchange 0.3135 shares of common stock, par value $6.25 per share, of
Phelps Dodge (the "Phelps Dodge Common Shares") for each outstanding share of
common stock, no par value (each, an "Cyprus Amax Share" and, collectively, the
"Cyprus Amax Shares"), of Cyprus Amax Minerals Company, a Delaware corporation
("Cyprus Amax"), including the associated preferred share purchase rights (each,
an "Cyprus Amax Right" and, collectively, the "Cyprus Amax Rights") issued
pursuant to the Cyprus Amax Rights Agreement, dated as of February 28, 1999, as
amended, between Cyprus Amax and The Bank of New York, as Rights Agent, upon the
terms and subject to the conditions set forth in the Prospectus, dated September
2, 1999 (the "Prospectus"), and in the related Letter of Transmittal (which
together constitute the "Offer"), enclosed herewith.


     THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, THE MINIMUM TENDER
CONDITION, THE RIGHTS PLAN CONDITION, THE FAIR PRICE CONDITION, THE PHELPS DODGE
STOCKHOLDER APPROVAL CONDITION, THE DGCL 203 CONDITION AND THE HSR CONDITION (IN
EACH CASE AS DEFINED IN THE PROSPECTUS). SEE "THE OFFER -- CONDITIONS OF THE
OFFER" IN THE PROSPECTUS.

     Phelps Dodge expressly reserves the right to (i) extend, amend or modify
the terms of the Offer in any manner and (ii) withdraw or terminate the Offer
and not accept for exchange any Cyprus Amax Shares if any of the conditions to
the Offer are not satisfied.

     Shareholders will be required to tender one Cyprus Amax Right for each
Cyprus Amax Share tendered, in order to effect a valid tender of Cyprus Amax
Shares, unless the Rights Plan Condition has been satisfied or waived. Unless
the Cyprus Amax Distribution Date (as defined in the Prospectus) occurs, a
tender of Cyprus Amax Shares will constitute a tender of the associated Cyprus
Amax Rights. See "The Offer -- Procedure for Tendering" in the Prospectus.
<PAGE>   2

     For your information and for forwarding to your clients for whom you hold
Cyprus Amax Shares registered in your name or in the name of your nominee(s), or
who hold Cyprus Amax Shares registered in their own names, we are enclosing the
following documents:


          1. Prospectus dated September 2, 1999;


          2. Letter of Transmittal (together with accompanying Substitute Form
     W-9) to be used by holders of Cyprus Amax Shares in accepting the Offer and
     tendering Cyprus Amax Shares;

          3. Notice of Guaranteed Delivery to be used to accept the Offer if
     certificates for Cyprus Amax Shares are not immediately available, if time
     will not permit all required documents to reach the Exchange Agent prior to
     the Expiration Date (as defined in the Prospectus) or if the procedure for
     book-entry transfer cannot be completed on a timely basis;


          4. A letter that may be sent to your clients for whose accounts you
     hold Cyprus Amax Shares registered in your name or in the name of your
     nominee(s), with space provided for obtaining such clients' instructions
     with regard to the Offer; and



          5. Guidelines of the Internal Revenue Service for Certification of
     Taxpayer Identification Number on Substitute Form W-9.



     Phelps Dodge will not pay any fees or commissions to any broker or dealer
or any other person (other than the fees of the Dealer Manager and the
Information Agent as described in the Prospectus) in connection with the
solicitation of tenders of Cyprus Amax Shares and Cyprus Amax Rights pursuant to
the Offer. Phelps Dodge will, however, upon request, reimburse you for customary
mailing and handling expenses incurred by you in forwarding the enclosed
materials to your clients. Phelps Dodge will pay or cause to be paid any stock
transfer taxes with respect to the transfer and sale of Cyprus Amax Shares to it
or its order pursuant to the Offer, except as otherwise provided in Instruction
6 of the Letter of Transmittal.



     YOUR PROMPT ACTION IS REQUESTED. WE URGE YOU TO CONTACT YOUR CLIENTS AS
PROMPTLY AS POSSIBLE. THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00
MIDNIGHT, NEW YORK CITY TIME, ON OCTOBER 1, 1999, UNLESS THE OFFER IS EXTENDED.


     In order to take advantage of the Offer, a duly executed and properly
completed Letter of Transmittal (or facsimile thereof), with any required
signature guarantees, or an Agent's Message (as defined in the Prospectus) in
connection with a book-entry transfer, and any other required documents, should
be sent to the Exchange Agent, and certificates evidencing the tendered Cyprus
Amax Shares should be delivered or such Cyprus Amax Shares should be tendered by
book-entry transfer, all in accordance with the instructions set forth in the
Letter of Transmittal and the Prospectus. If holders of Cyprus Amax Shares wish
to tender Cyprus Amax Shares, but it is impracticable for them to forward their
certificates or other required documents prior to the Expiration Date, a tender
may be effected by following the guaranteed delivery procedures specified under
"The Offer -- Procedure for Tendering" in the Prospectus.

     Any inquiries you may have with respect to the Offer should be addressed to
the Dealer Manager or the Information Agent at their respective addresses and
telephone numbers set forth on the back cover page of the Prospectus.

     Additional copies of the enclosed materials may be obtained from the
Information Agent, Innisfree M&A Incorporated by calling 1-877-750-5838 (Toll
Free).

                                          Very truly yours,

                                          Morgan Stanley & Co. Incorporated

                                        2
<PAGE>   3

     NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU
OR ANY OTHER PERSON AS AN AGENT OF PHELPS DODGE, THE DEALER MANAGER, THE
EXCHANGE AGENT OR THE INFORMATION AGENT, OR ANY AFFILIATE OF ANY OF THE
FOREGOING, OR AUTHORIZE YOU OR ANY OTHER PERSON TO GIVE ANY INFORMATION OR USE
ANY DOCUMENT OR MAKE ANY STATEMENT ON BEHALF OF ANY OF THEM IN CONNECTION WITH
THE OFFER OTHER THAN THE ENCLOSED DOCUMENTS AND THE STATEMENTS CONTAINED
THEREIN.

                                        3

<PAGE>   1

            OFFER TO EXCHANGE EACH OUTSTANDING SHARE OF COMMON STOCK
           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)

                                       OF

                          CYPRUS AMAX MINERALS COMPANY

                                      FOR

                         0.3135 SHARES OF COMMON STOCK

                                       OF

                            PHELPS DODGE CORPORATION


  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
TIME, ON OCTOBER 1, 1999, UNLESS THE OFFER IS EXTENDED. CYPRUS AMAX SHARES WHICH
  ARE TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE
                            EXPIRATION OF THE OFFER.


To Our Clients:


     Enclosed for your consideration are the Prospectus dated September 2, 1999
(the "Prospectus") and the related Letter of Transmittal (which together
constitute the "Offer") in connection with the Offer by Phelps Dodge
Corporation, a New York corporation ("Phelps Dodge"), to exchange 0.3135 shares
of common stock, par value $6.25 per share, of Phelps Dodge (the "Phelps Dodge
Common Shares") for each outstanding share of common stock, no par value (each,
a "Cyprus Amax Share" and, collectively, the "Cyprus Amax Shares") of Cyprus
Amax Minerals Company, a Delaware corporation ("Cyprus Amax"), including the
associated preferred share purchase rights (each an "Cyprus Amax Right") and,
collectively, the "Cyprus Amax Rights") issued pursuant to the Cyprus Amax
Rights Agreement, dated as of February 28, 1999, as amended, between Cyprus Amax
and The Bank of New York, as Rights Agent, upon the terms and subject to the
conditions set forth in the Offer.


     Shareholders whose certificates evidencing Cyprus Amax Shares ("Cyprus Amax
Share Certificates") are not immediately available or who cannot deliver their
Cyprus Amax Share Certificates and all other documents required by the Letter of
Transmittal to the Exchange Agent prior to the Expiration Date (as defined in
the Prospectus) or who cannot complete the procedure for delivery by book-entry
transfer to the Exchange Agent's account at a Book-Entry Transfer Facility (as
defined in "The Offer -- Exchange of Cyprus Amax Shares; Delivery of Phelps
Dodge Common Shares" in the Prospectus) on a timely basis and who wish to tender
their Cyprus Amax Shares must do so pursuant to the guaranteed delivery
procedure described in "The Offer -- Procedure for Tendering" in the Prospectus.
See Instruction 2 of the Letter of Transmittal. Delivery of documents to a
Book-Entry Transfer Facility in accordance with the Book-Entry Transfer
Facility's procedures does not constitute delivery to the Exchange Agent.

     THIS MATERIAL IS BEING FORWARDED TO YOU AS THE BENEFICIAL OWNER OF CYPRUS
AMAX SHARES HELD BY US FOR YOUR ACCOUNT BUT NOT REGISTERED IN YOUR NAME. WE ARE
THE HOLDER OF RECORD OF CYPRUS AMAX SHARES HELD BY US FOR YOUR ACCOUNT. A TENDER
OF SUCH CYPRUS AMAX SHARES CAN BE MADE ONLY BY US AS THE HOLDER OF RECORD AND
PURSUANT TO YOUR INSTRUCTIONS. THE LETTER OF TRANSMITTAL IS FURNISHED TO YOU FOR
YOUR INFORMATION ONLY AND CANNOT BE USED BY YOU TO TENDER CYPRUS AMAX SHARES
HELD BY US FOR YOUR ACCOUNT.

     Accordingly, we request instructions as to whether you wish to have us
tender on your behalf any or all of the Cyprus Amax Shares held by us for your
account, upon the terms and subject to the conditions set forth in the Offer.
<PAGE>   2

     Please note the following:


          1. Phelps Dodge is offering to acquire each outstanding Cyprus Amax
     Share in exchange for 0.3135 Phelps Dodge Common Shares.


          2. The Offer is being made for all of the outstanding Cyprus Amax
     Shares.


          3. The Offer and withdrawal rights will expire at 12:00 Midnight, New
     York City time, on October 1, 1999, unless the Offer is extended.


          4. The Offer is conditioned upon, among other things, the Minimum
     Tender Condition, the Rights Plan Condition, the Phelps Dodge Shareholder
     Approval Condition, the Fair Price Condition and the HSR Condition (in each
     case as defined in the Prospectus). See "The Offer -- Conditions of the
     Offer" in the Prospectus.

          5. Tendering shareholders will not be obligated to pay brokerage fees
     or commissions or, except as set forth in Instruction 6 of the Letter of
     Transmittal, stock transfer taxes on the transfer of Cyprus Amax Shares
     pursuant to the Offer.


     The Offer is made solely by the Prospectus dated September 2, 1999 and the
related Letter of Transmittal and any amendments or supplements thereto and is
being made to all holders of Cyprus Amax Shares. The Offer is not being made to,
nor will tenders be accepted from or on behalf of, holders of Cyprus Amax Shares
in any jurisdiction in which the making or acceptance thereof would not be in
compliance with the laws of such jurisdiction. However, Phelps Dodge may, in its
sole discretion, take such action as it may deem necessary to make the Offer in
any such jurisdiction and extend the Offer to holders of Cyprus Amax Shares in
such jurisdiction. In any jurisdiction where the securities, blue sky or other
laws require the Offer to be made by a licensed broker or dealer, the Offer
shall be deemed to be made on behalf of Phelps Dodge by Morgan Stanley & Co.
Incorporated, as Dealer Manager, or one or more registered brokers or dealers
licensed under the laws of such jurisdiction.


     If you wish to have us tender any or all of your Cyprus Amax Shares, please
so instruct us by completing, executing, detaching and returning to us the
instruction form contained in this letter. An envelope in which to return your
instructions to us is enclosed. If you authorize the tender of your Cyprus Amax
Shares, all such Cyprus Amax Shares will be tendered unless otherwise indicated
in such instruction form. PLEASE FORWARD YOUR INSTRUCTIONS TO US AS SOON AS
POSSIBLE TO ALLOW US AMPLE TIME TO TENDER CYPRUS AMAX SHARES ON YOUR BEHALF
PRIOR TO THE EXPIRATION OF THE OFFER.

                                        2
<PAGE>   3

            INSTRUCTIONS WITH RESPECT TO THE OFFER TO EXCHANGE EACH
                       OUTSTANDING SHARE OF COMMON STOCK
           (INCLUDING THE ASSOCIATED PREFERRED SHARE PURCHASE RIGHTS)

                                       OF

                            CYPRUS AMAX INCORPORATED

                                      FOR

                         0.3135 SHARES OF COMMON STOCK

                          OF PHELPS DODGE CORPORATION


     The undersigned acknowledge(s) receipt of your letter and the enclosed
Prospectus, dated September 2, 1999 (the "Prospectus"), and the related Letter
of Transmittal (which together constitute the "Offer") relating to the offer by
Phelps Dodge Corporation, a New York corporation ("Phelps Dodge"), to exchange
0.3135 shares of common stock, par value $6.25 per share, of Phelps Dodge for
each outstanding share of common stock, no par value (each, a "Cyprus Amax
Share" and, collectively, the "Cyprus Amax Shares"), of Cyprus Amax Minerals
Company, a Delaware corporation ("Cyprus Amax"), including the associated
preferred share purchase rights (each, an "Cyprus Amax Right" and, collectively,
the "Cyprus Amax Rights").



     You are instructed to tender to CAV Corporation, a Delaware corporation,
and a wholly owned subsidiary of Phelps Dodge the number of Cyprus Amax Shares
indicated below (or, if no number is indicated below, all Cyprus Amax Shares)
that are held by you for the account of the undersigned, upon the terms and
subject to the conditions set forth in the Offer.


Number of Cyprus Amax Shares to be Tendered:
- ------------------------------------------------------
Date:
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                                   SIGN HERE

Signature(s):
- --------------------------------------------------------------------------------
(Print Name(s)):
- --------------------------------------------------------------------------------
(Print Address(es)):
- --------------------------------------------------------------------------------
(Area Code and Telephone Number(s)):
- ---------------------------------------------------------------
(Taxpayer Identification or Social Security Number(s)):
- ----------------------------------------------


Unless otherwise indicated, it will be assumed that all of your Cyprus Amax
Shares held by us for your account are to be tendered.


                                        3

<PAGE>   1

            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9

GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE
PAYER -- Social Security numbers have nine digits separated by two hyphens:
i.e., 000-00-0000. Employer identification numbers have nine digits separated by
only one hyphen: i.e., 00-0000000. The table below will help determine the
number to give the payer.

<TABLE>
<C>  <S>                                 <C>
- ------------------------------------------------------------
                                         GIVE THE
              FOR THIS TYPE OF ACCOUNT:  SOCIAL SECURITY
                                         NUMBER OF --
- ------------------------------------------------------------

 1.  An individual's account             The individual
 2.  TWO or more individuals (Joint      The actual owner of
     account)                            the account or, if
                                         combined funds, any
                                         one of the
                                         individuals(1)
 3.  Husband and wife (joint account)    The actual owner of
                                         the account or, if
                                         joint funds, either
                                         person(1)
 4.  Custodian account of a minor        The minor(2)
     (Uniform Gift to Minors Act)
 5.  a. The usual revocable savings      The grantor-
        trust account (grantor is also   trustee(1)
        trustee)
     b. So-called trust account that is  The actual owner(1)
        not a legal or valid trust
        under state law
 6.  Sole proprietorship account         The Owner(4)
- ------------------------------------------------------------
- ------------------------------------------------------------
                                         GIVE THE EMPLOYER
              FOR THIS TYPE OF ACCOUNT:  IDENTIFICATION
                                         NUMBER OF--
- ------------------------------------------------------------

 7.  A valid trust, estate, or pension   Legal entity (Do
     trust                               not furnish the
                                         identifying number
                                         of the personal
                                         representative or
                                         trustee unless the
                                         legal entity itself
                                         is not designated
                                         in the account
                                         title.)(5)
 8.  Corporate                           The corporation
 9.  Partnership                         The partnership
10.  Association, club, religious,       The organization
     charitable, or educational, or
     other tax-exempt organization
11.  A broker or registered nominee      The broker or
                                         nominee
12.  Account with the Department of      The public entity
     Agriculture in the name of a
     public entity (such as a state or
     local government, school district,
     or prison) that receives
     agricultural program payments
- ------------------------------------------------------------
</TABLE>

(1) List first and circle the name of the person whose number you furnish.
(2) Circle the minor's name and furnish the minor's social security number.
(3) Show the name of the owner.
(4) List first and circle the name of the legal trust, estate, or pension trust.

NOTE: If no name is circled when there is more than one name, the number will be
      considered to be that of the first name listed.
<PAGE>   2

            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9

                                     PAGE 2

OBTAINING A NUMBER
If you don't have a taxpayer identification number or you don't know your
number, obtain Form SS-5, Application for a Social Security Number Card, Form
W-7, Application for IRS Individual Taxpayer Identification Number or Form SS-4,
Application for Employer Identification Number, at the local office of the
Social Security Administration or the Internal Revenue Service and apply for a
number.

PAYEE EXEMPT FROM BACKUP WITHHOLDING
Payees that may be exempt from backup withholding include the following:
  - A corporation.
  - A financial institution.

PAYEES THAT ARE EXEMPT FROM BACKUP WITHHOLDING INCLUDE THE FOLLOWING:
  - An organization exempt from tax under Section 501(a) or an individual
    retirement plan.
  -  --The United States or any agency or instrumentality thereof.
  - A state, the District of Columbia, a possession of the United States or any
    subdivision or instrumentality thereof.
  -  --A foreign government, a political subdivision of a foreign government or
    any agency or instrumentality thereof.
  - An international organization or any agency or instrumentality thereof.
  - A registered dealer in securities or commodities registered in the U.S., the
    District of Columbia, or a possession of the U.S.
  - A real estate investment trust.
  - A common trust fund operated by a bank under Section 584(a).
  - A trust exempt from tax under Section 664 or described in Section 4947.
  - An entity registered at all times under the Investment Company Act of 1940.
  -  --A foreign central bank of issue.

  Payments of dividends and patronage dividends not generally subject to backup
withholding include the following:
  - Payments to nonresident aliens subject to withholding under section 1441.
  - Payments to partnerships not engaged in a trade or business in the U.S. and
    which have at least one nonresident alien partner.
  - Payments of patronage dividends where the amount received is not paid in
    money.
  - Payments made by certain foreign organizations.

  Payments of interest not generally subject to backup withholding include the
following:
  - Payments of interest on obligations issued by individuals. NOTE: You may be
    subject to backup withholding if this interest is $600 or more and is paid
    in the course of the payer's trade or business and you have not provided
    your correct taxpayer identification number to the payer.
  - Payments of tax-exempt interest (including exempt interest dividends under
    section 852).
  - Payments described in section 6049(b)(5) to non-resident aliens.
  - Payments on tax-free covenant bonds under section 1451.
  - Payments made by certain foreign organizations.

JOINT FOREIGN PAYEES
Backup withholding applies unless:
    1. Every joint payee provides the statement regarding foreign status; or
    2. Anyone of the joint payees who has not established foreign status
supplies a TIN.

  If anyone of the joint payees who has not established foreign status supplies
a TIN, that number is the TIN that must be used for purposes of backup
withholding and information reporting.

  Exempt payees described above should file Form W-9 to avoid possible erroneous
backup withholding. FILE THIS FORM WITH THE PAYER, ENTER YOUR CORRECT TAXPAYER
IDENTIFICATION NUMBER IN PART I, WRITE "EXEMPT" IN PART II AND SIGN AND DATE THE
FORM.

  Certain payments other than interest, dividends and patronage dividends that
are not subject to information reporting are also not subject to backup
withholding. For details, see the regulations under sections 6041, 6041(a), 6045
and 6050A.

PRIVACY ACT NOTICE.--Section 6109 of the Internal Revenue Code requires most
recipients of dividend, interest or other payments to give taxpayer
identification numbers to payers who must report the payments to the IRS. The
IRS uses the numbers for identification purposes. Payers must be given the
numbers whether or not recipients are required to file tax returns. Payers must
generally withhold 31% of taxable interest, dividend and certain other payments
to a payee who does not furnish a taxpayer identification number to a payer.
Certain penalties may also apply.

PENALTIES
(1) PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER.--If you fail
to furnish your taxpayer identification number to a payer, you are subject to a
penalty of $50 for each such failure unless your failure is due to reasonable
cause and not to willful neglect.
(2) CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING.--If you
make a false statement with no reasonable basis which results in no imposition
of backup withholding, you are subject to a penalty of $500.
(3) CRIMINAL PENALTY FOR FALSIFYING INFORMATION.--Falsifying certifications or
affirmations may subject you to criminal penalties including fines and/or
imprisonment.

                  FOR ADDITIONAL INFORMATION CONTACT YOUR TAX
                  CONSULTANT OR THE INTERNAL REVENUE SERVICE.

<PAGE>   1

     This announcement is neither an offer to purchase nor a solicitation of an
offer to purchase any securities. The Offer is made solely in the Prospectus
dated September   , 1999 and the related Letter of Transmittal and Notice of
Guaranteed Delivery and is not being made to, nor will tenders be accepted from
or on behalf of, holders of Shares in any jurisdiction in which the making of
the Offer or the acceptance thereof would not be in compliance with the laws of
such jurisdiction. In any jurisdiction where the securities, blue sky or other
laws require the Offer to be made by a licensed broker or dealer, the Offer
shall be deemed to be made on behalf of Phelps Dodge Corporation by Morgan
Stanley Dean Witter or one or more registered brokers or dealers that are
licensed under the laws of such jurisdiction.

                          NOTICE OF OFFER TO EXCHANGE
                     EACH OUTSTANDING SHARE OF COMMON STOCK
                                       OF
                          CYPRUS AMAX MINERALS COMPANY
                                      FOR
                         0.3135 SHARES OF COMMON STOCK
                                       OF
                            PHELPS DODGE CORPORATION

     Phelps Dodge Corporation, a New York corporation (the "Company"), is
offering upon the terms and subject to the conditions set forth in the
Prospectus, dated September   , 1999 (the "Prospectus"), and in the related
Letter of Transmittal and Notice of Guaranteed Delivery (which together
constitute the "Offer") to exchange each outstanding Share of Common Stock, no
par value per share (each a "Share" and collectively the "Shares"), of Cyprus
Amax Minerals Company, a corporation incorporated under the laws of Delaware
("Cyprus Amax"), for shares of common stock, par value $6.25 per share, of the
Company (the "Phelps Dodge Common Shares") on the basis of 0.3135 Phelps Dodge
Common Shares for each Share validly tendered on or prior to the Expiration Date
(as defined below) and not properly withdrawn. The Company is making the Offer
through its wholly owned subsidiary, CAV Corporation, which is a Delaware
corporation. The Company is also making a separate offer to exchange 0.4098
shares of Phelps Dodge Common Shares for each outstanding share of ASARCO
Incorporated, a New Jersey corporation.

  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
          TIME, ON                1999, UNLESS THE OFFER IS EXTENDED.

     The purpose of the Offer is to obtain control of, and ultimately the entire
common equity interest in, Cyprus Amax. Phelps Dodge intends, as soon as
practicable after consummation of the Offer, to seek to have Cyprus Amax merge
with and into a subsidiary of Phelps Dodge (the "Phelps Dodge/Cyprus Amax
Merger"), in which each outstanding Share (except for Shares held by Cyprus
Amax, Phelps Dodge or any of their subsidiaries) would be converted into the
right to receive 0.3135 Phelps Dodge Common Shares.

     The Offer is conditioned upon, among other things, (i) there being validly
tendered and not withdrawn prior to the Expiration Date a number of Shares which
will constitute at least a majority of the total number of outstanding Shares on
a fully diluted basis as of the date the Shares are accepted for exchange by
Phelps Dodge pursuant to the Offer, (ii) the board of directors of Cyprus Amax
having redeemed the Cyprus Amax preferred share purchase rights (the "Cyprus
Amax Rights") or amended the Cyprus Amax rights agreement (the "Cyprus Amax
Rights Agreement") so that the Cyprus Amax Rights would not be triggered by the
Offer and the Phelps Dodge/Cyprus Amax Merger, or a court of competent
jurisdiction invalidates the Cyprus Amax Rights Agreement, (iii) either (a) the
board of directors of Cyprus Amax approves the Offer for purposes of Section 203
of the Delaware General Corporation Law (the "DGCL") or (b) Phelps Dodge
acquires 85% or more of the voting stock of Cyprus Amax pursuant to the Offer;
(iv) either (a) the board of directors of Cyprus Amax approves the Phelps
Dodge/Cyprus Amax Merger for purposes of Article Sixth of the Cyprus Amax
Restated of Incorporation or (b) Phelps Dodge acquires 75% or more of the
outstanding voting stock of Cyprus Amax; (v) approval of the issuance of shares
of Phelps Dodge Common Shares pursuant to the Offer and the Phelps Dodge/Cyprus
Amax Merger by the holders, of a majority of the of Phelps Dodge Common Shares
voted at a meeting at which the total number of votes cast represents over 50%
interest of all Phelps Dodge Common Shares entitled to vote on the proposal,
(vi) the waiting period (and any extension thereof) applicable to the Offer
under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended,
having expired or been terminated, and (vii) the other conditions to the Offer
and the Phelps Dodge/Cyprus Amax Merger, as set forth in the Prospectus, having
been satisfied or waived, as specified therein.

     The term "Expiration Date" means 12:00 midnight, New York City time, on
               , 1999, unless and until Phelps Dodge, in its sole discretion,
shall have extended the period of time during which the Offer is open, in which
event
<PAGE>   2

the term "Expiration Date" shall mean the latest time and date at which the
Offer, as so extended by Phelps Dodge, will expire.

     Upon the terms and subject to the conditions of the Offer (including, if
the Offer is extended or amended, the terms and conditions of any such extension
or amendment), Phelps Dodge will accept for exchange, and will exchange, Shares
validly tendered and not withdrawn as promptly as practicable after the
Expiration Date. In addition, subject to applicable rules of the Securities and
Exchange Commission (the "SEC"), Phelps Dodge expressly reserves the right to
delay acceptance or the exchange of Shares in order to comply with any
applicable law. In all cases, the exchange of Shares tendered and accepted for
exchange pursuant to the Offer will be made only after receipt by ChaseMellon
Shareholder Services, L.L.C. (the "Exchange Agent") of certificates for Shares
(or a confirmation of a book-entry transfer of such Shares into the Exchange
Agent's account at The Depository Trust Company (the "DTC")), a properly
completed and duly executed Letter of Transmittal (or facsimile thereof), or an
agent's message (as defined in the Prospectus) in connection with a book-entry
transfer, and any other required documents.

     For purposes of the Offer, Phelps Dodge will be deemed to have accepted for
exchange Shares validly tendered and not withdrawn as, if and when Phelps Dodge
gives oral or written notice to the Exchange Agent of its acceptance of the
tenders of such Shares pursuant to the Offer. Delivery of Phelps Dodge Common
Shares in exchange for Shares pursuant to the Offer and cash in lieu of
fractional shares of Phelps Dodge Common Shares will be made by the Exchange
Agent as soon as practicable after receipt of such notice. The Exchange Agent
will act as agent for tendering shareholders for the purpose of receiving Phelps
Dodge Common Shares and cash to be paid in lieu of fractional Phelps Dodge
Common Shares from Phelps Dodge and transmitting such Phelps Dodge Common Shares
and cash to tendering Cyprus Amax shareholders. Under no circumstances will
interest with respect to fractional shares be paid by Phelps Dodge by reason of
any delay in making such exchange.

     Shares tendered pursuant to the Offer may be withdrawn pursuant to the
procedures set forth in the Prospectus at any time prior to the Expiration Date
and, unless theretofore accepted for exchange by Phelps Dodge pursuant to the
Offer, may also be withdrawn at any time after                , 1999. Except as
otherwise provided in the Prospectus, tenders of Shares are irrevocable.

     For a withdrawal to be effective, a written, telegraphic, telex or
facsimile transmission notice of withdrawal must be timely received by the
Exchange Agent at one of its addresses set forth on the back cover of the
Prospectus and must specify the name of the person having tendered the Shares to
be withdrawn, the number of Shares to be withdrawn and the name of the
registered holder of the Shares to be withdrawn, if different from that of the
person who tendered such Shares. The signature(s) on the notice of withdrawal
must be guaranteed by a financial institution (including most banks, savings and
loan associations and brokerage houses) which is a participant in the Securities
Transfer Agents Medallion Program, the New York Stock Exchange Medallion
Signature Program or the Stock Exchange Medallion Program (an "Eligible
Institution") unless such Shares have been tendered for the account of any
Eligible Institution. If Shares have been tendered pursuant to the procedures
for book-entry tender as set forth in the Prospectus, any notice of withdrawal
must specify the name and number of the account at DTC to be credited with the
withdrawn Shares and must otherwise comply with DTC's procedures. If
certificates have been delivered or otherwise identified to the Exchange Agent,
the name of the registered holder and the certificate numbers of the particular
certificates evidencing the Shares withdrawn must also be furnished to the
Exchange Agent as aforesaid prior to the physical release of such certificates.

     All questions as to the form and validity (including time of receipt) of
any notice of withdrawal will be determined by Phelps Dodge, in its sole
discretion, which determination shall be final and binding. Neither Phelps
Dodge, the Exchange Agent, the Information Agent, the Dealer Manager nor any
other person will be under any duty to give notification of any defects or
irregularities in any notice of withdrawal or will incur any liability for
failure to give any such notification. Any Shares properly withdrawn will be
deemed not to have been validly tendered for purposes of the Offer. However,
withdrawn Shares may be retendered by following one of the procedures described
under the caption "The Offer -- Procedure for Tendering" in the Prospectus at
any time prior to the Expiration Date.

     Subject to the applicable rules and regulations of the SEC, Phelps Dodge
reserves the right, in its sole discretion, at any time or from time to time,
(i) to delay acceptance for, or, regardless of whether such Shares were
theretofore accepted for exchange, exchange of, any Shares pursuant to the Offer
or to terminate the Offer and not accept for exchange or exchange any Shares not
theretofore accepted for exchange, or exchanged, upon the failure of any of the
conditions of the Offer to be satisfied and (ii) to waive any condition (other
than the Phelps Dodge Stockholder Approval Condition, the HSR Condition, the
condition relating to the effectiveness of the Registration Statement and, after
the Phelps Dodge Stockholder Approval Condition has been satisfied, the
condition relating to the legal opinion as to tax matters (each as defined or
described in the Prospectus) or otherwise amend the Offer in any respect, by
giving oral or written notice of such delay, termination or amendment to the
Exchange Agent and by making a public announcement thereof.
<PAGE>   3

     The information required to be disclosed by paragraph (e)(1)(vii) of Rule
14d-6 under the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), is incorporated herein by reference.

     Requests have been made to Cyprus Amax pursuant to Section 220 of the DGCL
for the use of Cyprus Amax's stockholder lists and security position listings
for the purpose of disseminating the Offer to holders of Shares. The Prospectus,
the related Letter of Transmittal and the other relevant materials will be
mailed to record holders of Shares, and will be furnished to brokers, dealers,
banks, trust companies and similar persons whose names, or the names of whose
nominees, appear on the stockholder lists, or, if applicable, who are listed as
participants in a clearing agency's security position listing, for subsequent
transmittal to beneficial owners of Shares, by Phelps Dodge following receipt of
such lists or listings from Cyprus Amax, or by Cyprus Amax if Cyprus Amax so
elects.

     THE PROSPECTUS AND THE LETTER OF TRANSMITTAL CONTAIN IMPORTANT INFORMATION
THAT SHOULD BE READ BEFORE ANY DECISION IS MADE WITH RESPECT TO THE OFFER.

     Questions and requests for assistance, or for additional copies of the
Prospectus, the Letter of Transmittal, the Notice of Guaranteed Delivery or
other Offer documents may be directed to the Information Agent or the Dealer
Manager at their respective telephone numbers and addresses listed below.
Holders of Shares may also contact brokers, dealers, commercial banks and trust
companies or other nominees for assistance concerning the Offer. Copies of the
foregoing will be furnished at Phelps Dodge's expense. No fees or commissions
will be payable to brokers, dealers or other persons other than the Dealer
Manager and the Information Agent for soliciting tenders of Shares pursuant to
the Offer.

                    The Information Agent for the Offer is:

                           INNISFREE M&A INCORPORATED
                         501 Madison Avenue, 20th Floor
                            New York, New York 10022
                         Call Toll-Free: 1-877-750-5838
                 Banks and Brokers call collect: (212) 750-5833

                      The Dealer Manager for the Offer is:

                           MORGAN STANLEY DEAN WITTER
                                 1585 Broadway
                            New York, New York 10036
                                 (212) 761-4000

September   , 1999

<PAGE>   1

                                                                      EXHIBIT(d)

                                                               September 2, 1999

Phelps Dodge Corporation
2600 North Central Avenue
Phoenix, AZ 85004-3014

    Offer to Exchange Common Stock of Phelps Dodge Corporation
       for Common Stock of Cyprus Amax Minerals Company

Ladies and Gentlemen:

     You have requested our opinion as to certain United States federal income
tax consequences of your offer to exchange shares of your common stock for
shares of common stock of Cyprus Amax Minerals Company, a Delaware corporation,
and of the merger of CAV Corporation, a Delaware subsidiary wholly owned by you,
with Cyprus Amax Minerals Company. We hereby confirm our opinion as set forth
under the heading "Material U.S. Federal Income Tax Considerations" in the
Prospectus dated September 2, 1999.

     We hereby consent to the reference to us under the heading "Material U.S.
Federal Income Tax Considerations" in the Prospectus and to the filing of this
opinion as an exhibit to the related Registration Statement on Form S-4 filed
with the Securities and Exchange Commission. In giving this consent, we do not
hereby admit that we are within the category of persons whose consent is
required under Section 7 of the Securities Act of 1933, or the rules and
regulations of the Securities and Exchange Commission promulgated thereunder.

                                          Very truly yours,

                                          SHEARMAN & STERLING

PHB/PMM


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