<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY INFORMATION EXTRACTED FROM THE CONSOLIDATED BALANCE SHEET AND THE CONSOLIDATED STATEMENT OF INCOME FILED AS PART OF THE QUARTERLY REPORT ON FORM 10-Q AND IS QUALIFIED IN ITS ENTIRETY BY SUCH QUARTERLY REPORT ON FORM 10-Q. </LEGEND> <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-END> JUN-30-1998 <CASH> $43,091 <SECURITIES> $0 <RECEIVABLES> $135,111 <ALLOWANCES> $2,612 <INVENTORY> $109,307 <CURRENT-ASSETS> $303,124 <PP&E> $1,214,345 <DEPRECIATION> $718,417 <TOTAL-ASSETS> $899,701 <CURRENT-LIABILITIES> $119,643 <BONDS> $0 <PREFERRED-MANDATORY> $0 <PREFERRED> $0 <COMMON> $528 <OTHER-SE> $524,592 <TOTAL-LIABILITY-AND-EQUITY> $899,701 <SALES> $419,252 <TOTAL-REVENUES> $419,252 <CGS> $285,253 <TOTAL-COSTS> $352,860 <OTHER-EXPENSES> $0 <LOSS-PROVISION> $0 <INTEREST-EXPENSE> $1,707 <INCOME-PRETAX> $65,867 <INCOME-TAX> $21,407 <INCOME-CONTINUING> $44,460 <DISCONTINUED> $0 <EXTRAORDINARY> $0 <CHANGES> $0 <NET-INCOME> $44,460 <EPS-PRIMARY> $0.83 <EPS-DILUTED> $0.83