<ARTICLE> 5
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               JUN-30-1997
<CASH>                                           8,753
<SECURITIES>                                         0
<RECEIVABLES>                                  124,419
<ALLOWANCES>                                     4,804
<INVENTORY>                                    136,801
<CURRENT-ASSETS>                               320,101
<PP&E>                                       1,250,134
<DEPRECIATION>                                 541,038
<TOTAL-ASSETS>                               1,596,399
<CURRENT-LIABILITIES>                          192,164
<BONDS>                                        448,695
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       123,941
<OTHER-SE>                                     498,414
<TOTAL-LIABILITY-AND-EQUITY>                 1,596,399
<SALES>                                        550,211
<TOTAL-REVENUES>                               550,211
<CGS>                                          450,141
<TOTAL-COSTS>                                  450,141
<OTHER-EXPENSES>                                31,855
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              11,907
<INCOME-PRETAX>                                 56,308
<INCOME-TAX>                                    18,151
<INCOME-CONTINUING>                             38,157
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    38,157
<EPS-PRIMARY>                                     1.29
<EPS-DILUTED>                                     1.29