Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 6,891	$ 7,232
Restricted cash	9,316	4,921
Accounts receivable	12,582	15,438
Inventory	36,318	36,685
Parts and supplies	40,137	39,104
Prepaid expenses	1,808	1,478
Total current assets	107,052	104,858
Property, plant and equipment:
Land and mineral rights	70,307	70,307
Buildings and equipment	435,329	429,857
Mine development	94,725	92,458
Finance lease right-of-use assets	13,034	13,034
Total property, plant and equipment	613,395	605,656
Less - accumulated depreciation, depletion and amortization	(360,624)	(347,952)
Total property, plant and equipment, net	252,771	257,704
Equity method investments	2,370	2,607
Other assets	3,904	3,951
Total assets	366,097	369,120
Current liabilities:
Current portion of bank debt, net	16,965	4,095
Accounts payable and accrued liabilities	45,652	44,298
Current portion of lease financing	7,067	6,912
Contract liabilities - current	107,368	97,598
Total current liabilities	177,052	152,903
Long-term liabilities:
Bank debt, net	4,000	37,394
Long-term lease financing	6,921	8,749
Asset retirement obligations	15,386	14,957
Contract liabilities - long-term	42,539	49,121
Other	4,851	1,711
Total long-term liabilities	73,697	111,932
Total liabilities	250,749	264,835
Commitments and contingencies (Note 16)
Stockholders' equity:
Preferred stock, $.10 par value, 10,000 shares authorized; none issued
Common stock, $.01 par value, 100,000 shares authorized; 42,978 and 42,621 issued and outstanding, as of March 31, 2025 and December 31, 2024, respectively	430	426
Additional paid-in capital	190,378	189,298
Retained earnings (deficit)	(75,460)	(85,439)
Total stockholders' equity	115,348	104,285
Total liabilities and stockholders' equity	$ 366,097	$ 369,120