<ARTICLE>                     5
<LEGEND>
This  schedule  contains  summary  financial   information  extracted  from  the
Condensed  Consolidated Balance Sheet at June 30, 1997 and the related Condensed
Statement of Consolidated  Operations for the six months ended June 30, 1997 and
is qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER>                                   1,000
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                         DEC-31-1997
<PERIOD-END>                              JUN-30-1997
<CASH>                                         87,840
<SECURITIES>                                  163,788
<RECEIVABLES>                                  37,789
<ALLOWANCES>                                        0
<INVENTORY>                                    88,579
<CURRENT-ASSETS>                              395,701
<PP&E>                                      2,016,633
<DEPRECIATION>                              1,022,514
<TOTAL-ASSETS>                              1,471,988
<CURRENT-LIABILITIES>                         103,735
<BONDS>                                       188,730
<PREFERRED-MANDATORY>                               0
<PREFERRED>                                         0
<COMMON>                                      146,728
<OTHER-SE>                                    614,265
<TOTAL-LIABILITY-AND-EQUITY>                1,471,988
<SALES>                                       338,460
<TOTAL-REVENUES>                              418,846
<CGS>                                         295,448<F1> 
<TOTAL-COSTS>                                 314,942<F2>
<OTHER-EXPENSES>                               25,440<F3>
<LOSS-PROVISION>                                    0
<INTEREST-EXPENSE>                              5,433
<INCOME-PRETAX>                                73,031
<INCOME-TAX>                                   33,244
<INCOME-CONTINUING>                            33,638
<DISCONTINUED>                                      0
<EXTRAORDINARY>                                     0
<CHANGES>                                           0
<NET-INCOME>                                   33,638
<EPS-PRIMARY>                                    0.23
<EPS-DILUTED>                                       0

<FN>
<F1> Includes Production costs and Depreciation, depletion and amortization from
Condensed Statement of Consolidated Operations.
<F2> Incluees Production costs and Depreciation,  depletion and amortization and
Administrative  and general  expense from  Condensed  Statement of  Consolidated
Operations.
<F3> Includes  Exploration expense and Other expense from Condensed Statement of
Consolidated Operations.
</FN>