<ARTICLE> 5
<MULTIPLIER> 1,000

                                        
<PERIOD-TYPE>                              6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-END>                               JUN-30-1999
<CASH>                                           1,510
<SECURITIES>                                         0
<RECEIVABLES>                                   23,243
<ALLOWANCES>                                         0
<INVENTORY>                                     22,448
<CURRENT-ASSETS>                                51,081
<PP&E>                                       1,051,925
<DEPRECIATION>                                (499,425)
<TOTAL-ASSETS>                                 627,597
<CURRENT-LIABILITIES>                           40,165
<BONDS>                                        267,800
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         2,774
<OTHER-SE>                                     187,787
<TOTAL-LIABILITY-AND-EQUITY>                   627,597
<SALES>                                        130,432
<TOTAL-REVENUES>                               134,259
<CGS>                                                0
<TOTAL-COSTS>                                  112,789
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               8,388
<INCOME-PRETAX>                                 12,177
<INCOME-TAX>                                     4,749
<INCOME-CONTINUING>                              7,428
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     7,428
<EPS-BASIC>                                     0.30
<EPS-DILUTED>                                     0.30
<FN>
The information has been prepared in accordance with SFAS No. 128.
Basic and dilted EPS have been entered in place of primary and fully diluted,
respectively.
</FN>