<ARTICLE> 5
<MULTIPLIER> 1,000
       
                                        
<PERIOD-TYPE>                              3-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-END>                               MAR-31-1998
<CASH>                                           2,393
<SECURITIES>                                         0
<RECEIVABLES>                                   37,939
<ALLOWANCES>                                         0
<INVENTORY>                                     15,656
<CURRENT-ASSETS>                                62,135
<PP&E>                                         975,484
<DEPRECIATION>                                (379,687)
<TOTAL-ASSETS>                                 683,839
<CURRENT-LIABILITIES>                           54,552
<BONDS>                                        256,072
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         2,774   
<OTHER-SE>                                     226,480
<TOTAL-LIABILITY-AND-EQUITY>                   683,839
<SALES>                                         80,852
<TOTAL-REVENUES>                                82,956
<CGS>                                                0
<TOTAL-COSTS>                                   63,033
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               4,178
<INCOME-PRETAX>                                 14,872
<INCOME-TAX>                                     5,800
<INCOME-CONTINUING>                              9,072
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     9,072
<EPS-PRIMARY>                                      .37
<EPS-DILUTED>                                      .37