<ARTICLE>               5
<LEGEND>
The schedule contains summary financial information extracted from the condensed
balance sheet as of March 31, 1997 and the condensed statement of income for the
three months ended March 31, 1997 and is qualified in its entirety by reference
to such financial statements.
</LEGEND>
<MULTIPLIER>                                    1000
       
                                             
<PERIOD-TYPE>                                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-END>                               MAR-31-1997
<CASH>                                           7,077
<SECURITIES>                                    48,782
<RECEIVABLES>                                  161,655
<ALLOWANCES>                                     5,947
<INVENTORY>                                    142,319
<CURRENT-ASSETS>                               378,016
<PP&E>                                       1,947,706
<DEPRECIATION>                                 884,957
<TOTAL-ASSETS>                               1,843,286
<CURRENT-LIABILITIES>                          255,581
<BONDS>                                        367,170
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        37,065
<OTHER-SE>                                     652,760
<TOTAL-LIABILITY-AND-EQUITY>                 1,843,286
<SALES>                                        271,192
<TOTAL-REVENUES>                               296,252
<CGS>                                          227,791
<TOTAL-COSTS>                                  227,791
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               7,942
<INCOME-PRETAX>                                 33,964
<INCOME-TAX>                                    12,739
<INCOME-CONTINUING>                             21,225
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    21,225
<EPS-PRIMARY>                                      .47
<EPS-DILUTED>                                      .47