Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
SALES AND OPERATING REVENUES:
Other revenues		$ 6,363	$ 3,763
Total sales and operating revenues		361,991	247,666
OPERATING EXPENSES:
Operating expenses		266,608	198,840
Depreciation, depletion and amortization		46,875	39,973
Asset impairment		0	1,588
Asset retirement obligations accretion		1,010	1,504
Asset retirement obligations change in estimate		0	(3,510)
Exploration costs		651	482
General and administrative		16,417	14,833
Total operating expenses		331,561	253,710
INCOME (LOSS) FROM OPERATIONS		30,430	(6,044)
Interest expense (1)	[1]	(11,012)	(8,048)
Gain on extinguishment of debt		0	10,000
Equity method investment income		443	364
INCOME (LOSS) BEFORE INCOME TAXES		19,861	(3,728)
INCOME TAX EXPENSE:
Current		0	0
Deferred		1,756	26
Total income tax expense		1,756	26
NET INCOME (LOSS)		$ 18,105	$ (3,754)
NET INCOME (LOSS) PER SHARE:
Basic (in dollars per share)		$ 0.57	$ (0.12)
Diluted (in dollars per share)		$ 0.55	$ (0.12)
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)		32,043	30,614
Diluted (in shares)		33,649	30,614
(1) Interest Expense:
Interest on bank debt		$ 7,563	$ 8,510
Other interest		715	0
Amortization and swap related interest:
Payments on interest rate swap, net of changes in value		(867)	(3,026)
Amortization of debt issuance costs		3,601	2,564
Total amortization and swap related interest		2,734	(462)
Total interest expense	[1]	11,012	8,048
Coal Sales [Member]
SALES AND OPERATING REVENUES:
Revenues		289,376	243,903
Electric Sales [Member]
SALES AND OPERATING REVENUES:
Revenues		$ 66,252	$ 0

[1] Interest Expense: