<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 9-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-END> SEP-30-1998 <CASH> 7,828 <SECURITIES> 0 <RECEIVABLES> 7,575 <ALLOWANCES> 0 <INVENTORY> 8,468 <CURRENT-ASSETS> 27,164 <PP&E> 1,113,614 <DEPRECIATION> 793,140 <TOTAL-ASSETS> 349,807 <CURRENT-LIABILITIES> 23,609 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 0 <OTHER-SE> 0 <TOTAL-LIABILITY-AND-EQUITY> 349,807 <SALES> 106,169 <TOTAL-REVENUES> 106,169 <CGS> 44,392 <TOTAL-COSTS> 45,201 <OTHER-EXPENSES> 448 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 32 <INCOME-PRETAX> 61,581 <INCOME-TAX> 21,376 <INCOME-CONTINUING> 40,205 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 40,205 <EPS-PRIMARY> 0 <EPS-DILUTED> 0