<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM FORM 10-Q AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. </LEGEND> <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-END> JUN-30-1997 <CASH> 16322 <SECURITIES> 0 <RECEIVABLES> 78474 <ALLOWANCES> 0 <INVENTORY> 41794 <CURRENT-ASSETS> 159499 <PP&E> 1182224 <DEPRECIATION> 629426 <TOTAL-ASSETS> 883704 <CURRENT-LIABILITIES> 131115 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 209 <OTHER-SE> 148058 <TOTAL-LIABILITY-AND-EQUITY> 883704 <SALES> 383286 <TOTAL-REVENUES> 393576 <CGS> 340925 <TOTAL-COSTS> 360967 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 6792 <INCOME-PRETAX> 26352 <INCOME-TAX> 4200 <INCOME-CONTINUING> 22152 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 22152 <EPS-PRIMARY> 1.06 <EPS-DILUTED> 1.06