<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY INFORMATION EXTRACTED FROM THE CONSOLIDATED
BALANCE SHEET AND CONSOLIDATED STATEMENT OF INCOME FILED AS PART OF THE ANNUAL
REPORT ON FORM 10-Q AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH ANNUAL
REPORT ON FORM 10-Q.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-END>                               JUN-30-1997
<CASH>                                          $3,858
<SECURITIES>                                        $0
<RECEIVABLES>                                 $150,023
<ALLOWANCES>                                    $1,438
<INVENTORY>                                    $91,138
<CURRENT-ASSETS>                              $259,579
<PP&E>                                      $1,171,291
<DEPRECIATION>                                $674,262
<TOTAL-ASSETS>                                $849,528
<CURRENT-LIABILITIES>                         $122,148
<BONDS>                                             $0
<PREFERRED-MANDATORY>                               $0
<PREFERRED>                                         $0
<COMMON>                                          $553
<OTHER-SE>                                    $527,019
<TOTAL-LIABILITY-AND-EQUITY>                  $849,528
<SALES>                                       $406,069
<TOTAL-REVENUES>                              $406,069
<CGS>                                         $271,898
<TOTAL-COSTS>                                 $341,391
<OTHER-EXPENSES>                                    $0
<LOSS-PROVISION>                                    $0
<INTEREST-EXPENSE>                                $407
<INCOME-PRETAX>                                $64,792
<INCOME-TAX>                                   $24,252
<INCOME-CONTINUING>                            $40,540
<DISCONTINUED>                                      $0
<EXTRAORDINARY>                                     $0
<CHANGES>                                           $0
<NET-INCOME>                                   $40,540
<EPS-PRIMARY>                                    $0.73
<EPS-DILUTED>                                    $0.73