<TABLE> <S> <C>


<ARTICLE>                     5
<LEGEND>
This  schedule  contains  summary  financial   information  extracted  from  the
Condensed  Consolidated  Balance  Sheet at  September  30,  1997 and the related
Condensed  Statement  of  Consolidated  Operations  for the  nine  months  ended
September  30,  1997 and is  qualified  in its  entirety  by  reference  to such
financial statements.
</LEGEND>
<MULTIPLIER>                                                              1,000
       
<S>                                                                <C>
<PERIOD-TYPE>                   9-mos
<FISCAL-YEAR-END>                                                   DEC-31-1997
<PERIOD-END>                                                        SEP-30-1997
<CASH>                                                                   61,080
<SECURITIES>                                                            168,882
<RECEIVABLES>                                                            32,903
<ALLOWANCES>                                                                  0
<INVENTORY>                                                              89,366
<CURRENT-ASSETS>                                                        371,296
<PP&E>                                                                2,002,307
<DEPRECIATION>                                                        1,146,077
<TOTAL-ASSETS>                                                        1,334,470
<CURRENT-LIABILITIES>                                                   115,504
<BONDS>                                                                 222,183
<PREFERRED-MANDATORY>                                                         0
<PREFERRED>                                                                   0
<COMMON>                                                                146,744
<OTHER-SE>                                                              447,500
<TOTAL-LIABILITY-AND-EQUITY>                                          1,334,470
<SALES>                                                                 497,786
<TOTAL-REVENUES>                                                        577,070
<CGS>                                                                   439,814 <F1>
<TOTAL-COSTS>                                                           470,118 <F2>
<OTHER-EXPENSES>                                                        225,184 <F3>
<LOSS-PROVISION>                                                              0
<INTEREST-EXPENSE>                                                        7,659
<INCOME-PRETAX>                                                        (125,891)
<INCOME-TAX>                                                             (3,960)
<INCOME-CONTINUING>                                                    (130,044)
<DISCONTINUED>                                                                0
<EXTRAORDINARY>                                                               0
<CHANGES>                                                                     0
<NET-INCOME>                                                           (130,044)
<EPS-PRIMARY>                                                             (0.89)
<EPS-DILUTED>                                                                 0



<FN>
(1)  Includes Produciton costs and Depreciation,  depletion and amortization
     from Condensed Statement of Consolidated Operations.
(2)  Includes Production costs and Depreciation,  depletion and amortization and
     Administrative and general expense from Condensed Statement of Consolidated
     Operations.
(3)  Includes  Exploration  expense,  Write-downs  and other unusual charges and
     Other expense from Condensed Statement of Consolidated Operations.
</FN>
        

</TABLE>