<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-END> SEP-30-2000
<CASH> 296
<SECURITIES> 1,726
<RECEIVABLES> 62,485
<ALLOWANCES> (320)
<INVENTORY> 14,602
<CURRENT-ASSETS> 83,474
<PP&E> 1,156,648
<DEPRECIATION> (544,699)
<TOTAL-ASSETS> 697,369
<CURRENT-LIABILITIES> 104,251
<BONDS> 260,000
282,994
0
<COMMON> 0
<OTHER-SE> (57,544)
<TOTAL-LIABILITY-AND-EQUITY> 697,369
<SALES> 143,437
<TOTAL-REVENUES> 150,854
<CGS> 119,842
<TOTAL-COSTS> 119,842
<OTHER-EXPENSES> 0
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 17,044
<INCOME-PRETAX> 13,947
<INCOME-TAX> 5,546
<INCOME-CONTINUING> 12,150
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 12,150
<EPS-BASIC> 0.45
<EPS-DILUTED> 0.45
</TABLE>