<ARTICLE>                     5
<LEGEND>
This schedule contains financial information extracted from SEC filing Form 10-Q
and is qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER>                                            1,000
       
                               
<PERIOD-TYPE>                  3-MOS
<FISCAL-YEAR-END>                                 DEC-31-1997
<PERIOD-START>                                    JAN-01-1997
<PERIOD-END>                                      MAR-31-1997
<CASH>                                                 $7,323
<SECURITIES>                                                0
<RECEIVABLES>                                          76,442
<ALLOWANCES>                                            2,264
<INVENTORY>                                             7,670
<CURRENT-ASSETS>                                      103,760
<PP&E>                                                568,460
<DEPRECIATION>                                        231,031
<TOTAL-ASSETS>                                        857,988
<CURRENT-LIABILITIES>                                  97,471
<BONDS>                                                     0
<PREFERRED-MANDATORY>                                       0
<PREFERRED>                                                 0
<COMMON>                                                  378
<OTHER-SE>                                            516,423
<TOTAL-LIABILITY-AND-EQUITY>                          857,988
<SALES>                                               150,621
<TOTAL-REVENUES>                                      150,621
<CGS>                                                       0
<TOTAL-COSTS>                                         127,831
<OTHER-EXPENSES>                                      (6,297)
<LOSS-PROVISION>                                            0
<INTEREST-EXPENSE>                                      2,668
<INCOME-PRETAX>                                        26,419
<INCOME-TAX>                                           11,062
<INCOME-CONTINUING>                                    15,357
<DISCONTINUED>                                              0
<EXTRAORDINARY>                                             0
<CHANGES>                                                   0
<NET-INCOME>                                          $15,537
<EPS-PRIMARY>                                           $0.41
<EPS-DILUTED>                                           $0.40