<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE COMPANY'S UNAUDITED FINANCIAL STATEMENTS AS OF AND FOR THE PERIOD ENDING JUNE 30, 1998, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS <MULTIPLIER> 1,000 <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-END> JUN-30-1998 <PERIOD-TYPE> 6-MOS <CASH> 3,553 <SECURITIES> 0 <RECEIVABLES> 73,257 <ALLOWANCES> 0 <INVENTORY> 20,894 <CURRENT-ASSETS> 113,145 <PP&E> 321,374 <DEPRECIATION> 149,258 <TOTAL-ASSETS> 341,450 <CURRENT-LIABILITIES> 68,776 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 18,356 <OTHER-SE> 107,646 <TOTAL-LIABILITY-AND-EQUITY> 341,450 <SALES> 254,260 <TOTAL-REVENUES> 253,935 <CGS> 225,781 <TOTAL-COSTS> 7,402 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 4,945 <INCOME-PRETAX> 15,807 <INCOME-TAX> 5,216 <INCOME-CONTINUING> 10,591 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 10,591 <EPS-PRIMARY> 0.58 <EPS-DILUTED> 0.58