<ARTICLE>                5
<LEGEND>                 This schedule  contains summary  financial  information
                         extracted   from    Consolidated    Summary   Financial
                         Statements  and Notes included in this 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>                                       6,900
<SECURITIES>                                     0
<RECEIVABLES>                              121,400
<ALLOWANCES>                                     0
<INVENTORY>                                249,400
<CURRENT-ASSETS>                           483,400
<PP&E>                                   2,549,900
<DEPRECIATION>                          (1,271,500)
<TOTAL-ASSETS>                           2,527,700
<CURRENT-LIABILITIES>                      306,200
<BONDS>                                    469,600
<PREFERRED-MANDATORY>                            0
<PREFERRED>                                      0
<COMMON>                                   117,000
<OTHER-SE>                               1,332,000
<TOTAL-LIABILITY-AND-EQUITY>             2,527,700
<SALES>                                  1,187,900
<TOTAL-REVENUES>                         1,187,900
<CGS>                                    1,065,200
<TOTAL-COSTS>                            1,124,300
<OTHER-EXPENSES>                                 0
<LOSS-PROVISION>                                 0
<INTEREST-EXPENSE>                          15,800
<INCOME-PRETAX>                             63,600
<INCOME-TAX>                                34,200
<INCOME-CONTINUING>                         31,900
<DISCONTINUED>                                   0
<EXTRAORDINARY>                                  0
<CHANGES>                                        0
<NET-INCOME>                                31,900
<EPS-PRIMARY>                                     .29
<EPS-DILUTED>                                    0