<ARTICLE>               5
<LEGEND>
The schedule contains summary financial information extracted from the
condensed balance sheet as of September 30, 1997 and the condensed statement
of income for the nine months ended September 30, 1997 and is qualified in its
entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER>                                      1000
       
                                                
<PERIOD-TYPE>                                    9-MOS
<FISCAL-YEAR-END>                          DEC-31-1996
<PERIOD-END>                               SEP-30-1997
<CASH>                                             793
<SECURITIES>                                    14,100
<RECEIVABLES>                                  211,083
<ALLOWANCES>                                     6,983
<INVENTORY>                                    123,305
<CURRENT-ASSETS>                               373,997
<PP&E>                                       1,959,898
<DEPRECIATION>                                 923,154
<TOTAL-ASSETS>                               1,791,289
<CURRENT-LIABILITIES>                          267,076
<BONDS>                                        272,393
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        36,914
<OTHER-SE>                                     679,666
<TOTAL-LIABILITY-AND-EQUITY>                 1,791,289
<SALES>                                        905,861
<TOTAL-REVENUES>                               940,186
<CGS>                                          740,546
<TOTAL-COSTS>                                  740,546
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              22,515
<INCOME-PRETAX>                                 97,772
<INCOME-TAX>                                    36,396
<INCOME-CONTINUING>                             61,376
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    61,376
<EPS-PRIMARY>                                     1.36
<EPS-DILUTED>                                     1.35