<PAGE>
EXHIBIT 5.1
OPINION OF W.S. WALKER & COMPANY
[LETTERHEAD OF W.S. WALKER & COMPANY]
The Directors
Apex Silver Mines Limited
Caledonian House
Jennett Street
P.O. Box 1043
George Town
Grand Cayman
Cayman Islands
21 August 2000
Dear Sirs,
This opinion is delivered in connection with the filing of a Registration
Statement on Form S-1, as amended, on Form S-3 (the "Registration Statement")
with the Securities and Exchange Commission pursuant to the U.S. Securities Act
of 1933, as amended (the "Act"), by Apex Silver Mines Limited, a Cayman Islands
company ("Apex"), for the registration of the sale from time to time of up to
US$200,000,000 aggregate amount of (i) ordinary shares, par value US$0.01 per
share, of Apex ("Ordinary Shares"), (ii) depositary shares of Apex ("Depositary
Shares"), (iii) preference shares, par value US$0.01 per share of Apex
("Preference Shares"), (iv) warrants for the purchase of securities or other
rights ("Warrants"), (v) rights to purchase Ordinary Shares ("Ordinary Share
Purchase Rights") and (vi) senior debt securities and/or subordinated debt
securities of Apex ("Debt Securities") (each of the Ordinary Shares, the
Depositary Shares, the Preference Shares, the Warrants, the Ordinary Share
Purchase Rights and the Debt Securities referred to herein as a "Security" and
collectively referred to herein as, the "Securities").
For the purposes of giving this opinion, we have examined the documents (the
"Documents") listed in Schedule 1 hereto.
In giving this opinion we have relied upon the assumptions set out in Schedule 2
and the qualification set out in Schedule 3 hereto, which we have not
independently verified.
We are Attorneys-at-Law in the Cayman Islands and express no opinion as to any
laws other than the laws of the Cayman Islands in force and as interpreted at
the date hereof. Except as explicitly stated herein, we express no opinion in
relation to any representation or warranty contained in the documents nor upon
the commercial terms of the transactions contemplated by the documents.
<PAGE>
Based upon the foregoing examinations and assumptions and upon such searches as
we have conducted and having regard to legal considerations which we deem
relevant, we are of the opinion that under the law of the Cayman Islands:
1. With respect to each of the Ordinary Shares, when (i) the Board of
Directors of Apex or a committee thereof properly empowered (such Board of
Directors or committee being hereinafter referred to as the "Apex Board")
has taken all necessary corporate action to approve the issuance of and the
terms of the offering of the Ordinary Shares and related matters, and (ii)
entries have been made in the Register of Members of Apex and certificates
representing the Ordinary Shares have been duly executed, countersigned,
registered and delivered (a) for consideration approved by the Apex Board
or (b) upon consideration by way of conversion or exercise of any other
Security in accordance with the terms of such Security or the instrument
governing such Security providing for such conversion or exercise as
approved by the Apex Board, the Ordinary Shares will be duly authorized,
validly issued, fully paid and non-assessable.
2. With respect to the Preference Shares, when (i) the Apex Board has taken
all necessary corporate action to approve the issuance and terms of the
Preference Shares, the terms of the offering thereof and related matters,
including the adoption of resolutions establishing the terms of such
Preference Shares, and (ii) entries have been made in the Register of
Members of Apex and certificates representing the Preference Shares have
been executed, countersigned, registered and delivered (a) for
consideration approved by the Apex Board or (b) upon consideration by way
of conversion or exercise of any other Security in accordance with the
terms of such Security or the instrument governing such Security providing
for such conversion or exercise as approved by the Apex Board, the
Preference Shares will be duly authorized, validly issued, fully paid and
non-assessable.
3. With respect to the Depositary Shares, when (i) the Apex Board has taken
all necessary corporate action to approve the issuance and terms of the
Depositary Shares, the terms of the offering thereof and related matters,
including the adoption of resolutions establishing the terms of such
Depositary Shares, and (ii) entries have been made in the Register of
Members of Apex and certificates representing the Depositary Shares have
been executed, countersigned, registered and delivered (a) for
consideration approved by the Apex Board or (b) upon consideration by way
of conversion or exercise of any other Security in accordance with the
terms of such Security or the instrument governing such Security providing
for such conversion or exercise as approved by the Apex Board, the
Depositary Shares will be duly authorized, validly issued, fully paid and
non-assessable.
4. With respect to the Ordinary Share Purchase Rights, when (i) the Apex Board
has taken all necessary corporate action to approve the issuance and terms
of the Ordinary Share Purchase Rights, the terms of the offering thereof
and related matters, including the adoption of resolutions establishing the
terms of such Ordinary Share Purchase Rights, and (ii) certificates
representing the Ordinary Share Purchase Rights have been executed,
2
<PAGE>
countersigned, registered and delivered for consideration approved by the
Apex Board, the Ordinary Share Purchase Rights will be duly authorized and
validly issued.
5. With respect to the Warrants, when (i) the Apex Board has taken all
necessary corporate action to approve and enter into one or more relevant
warrant agreements or amendments or supplements thereto, as described in
the Registration Statement, as amended or supplemented, or any prospectus
or prospectus supplement and pursuant thereto, approve the issuance and
terms of the Warrants, the terms of the offering thereof and related
matters, including the adoption of resolutions establishing the terms of
such Warrants, and (ii) certificates representing the Warrants have been
executed, countersigned, registered and delivered for consideration
approved by the Apex Board, the Warrants will be duly authorized and
validly issued.
6. With respect to the Debt Securities, when (i) the Apex Board has taken all
necessary corporate action to approve and enter into one or more relevant
indentures or amendments or supplements thereto, as described in the
Registration Statement, as amended or supplemented, or any prospectus or
prospectus supplement and pursuant thereto, approve the issuance and terms
of the Debt Securities, the terms of the offering thereof and related
matters, including the adoption of resolutions establishing the terms of
such Debt Securities, and (ii) certificates representing the Debt
Securities have been executed, countersigned, registered and delivered for
consideration approved by the Apex Board, the Debt Securities will be duly
authorized and validly issued.
This opinion is limited to the matters referred to herein and shall not be
construed as extending to any other matter or document not referred to herein.
This opinion is given solely for your benefit and the benefit of your legal
advisers acting in that capacity in relation to this transaction and may not be
relied upon by any other person without our prior written consent.
This opinion is governed by and shall be construed in accordance with the laws
of the Cayman Islands.
We hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement and all references to our name in the Registration
Statement. In giving such consent, we do not hereby admit that we come within
the category of persons whose consent is required under Section 7 of the U.S.
Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereof.
Yours faithfully,
WALKERS
3
<PAGE>
Schedule 1
1. The Memorandum and Articles of Association of Apex dated 3 October 1997;
2. The Registration Statement; and
3. Such other documents as we have considered necessary for the purposes of
rendering this opinion.
4
<PAGE>
Schedule 2
The opinions hereinbefore given are based upon the following assumptions:
1. There are no provisions of the laws of any jurisdiction outside the Cayman
Islands which would be contravened by the execution or delivery of the
Documents and that, in so far as any obligation expressed to be incurred
under the Documents is to be performed in or is otherwise subject to the
laws of any jurisdiction outside the Cayman Islands, its performance will
not be illegal by virtue of the laws of that jurisdiction.
2. All authorizations, approvals, consents, licenses and exemptions required
by and all filings and other requirements of each of the parties to the
Documents outside the Cayman Islands to ensure the legality and validity of
the Documents will be duly obtained, made or fulfilled and will remain in
full force and effect and that any conditions to which they are subject
will be satisfied.
3. Payment in full for the Ordinary Shares, Depositary Shares and Preference
Shares will be received by Apex.
4. None of the parties to any of the Documents is a person, political faction
or body resident in or constituted under the laws of any country currently
the subject of United Nations Sanctions ("Sanctions") extended to the
Cayman Islands by the Order of Her Majesty in Council. At this date
Sanctions currently extend to Libya, Iraq, Kuwait, Haiti, The Federal
Republic of Yugoslavia, Sierra Leone, Liberia, Somalia, Rwanda, Serbia &
Montenegro, Angola, the Uniao Nacional para a Independencia Total de Angola
("UNITA"), Afghanistan, Eritrea or Ethiopia and the Taliban (an Afghan
political faction which calls itself the Islamic Emirate of Afghanistan).
5. The Minute Book of the Company examined by us on 18 August, 2000 as
provided to us by the Registered Office contains a complete and accurate
record of the business transacted by it.
6. The corporate records of the Company examined by us on 18 August, 2000 as
provided to us by the Registered Office constitute its complete corporate
records and that all matters required by law to be recorded therein are so
recorded.
7. The Cause Books of the Cayman Islands Grand Court maintained by the Clerk
of the Courts examined by us on 18 August, 2000 at 9:30 am at the Courts
Office constitute a complete record of the proceedings before the Grand
Court of the Cayman Islands.
5
<PAGE>
Schedule 3
Qualifications
The opinions hereinbefore given are subject to the following qualification:
1. The authorised capital of the Company is US$75,000,000 ordinary shares and
additional shares may not be issued above this amount without the passing
of a resolution of the shareholders of the Company to increase the
authorised share capital.
