Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities
Net loss	$ (5,387)	$ (13,364)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization, depletion and accretion	3,374	4,565
Stock-based compensation expense	1,435	1,108
Operating lease expense	1,049	1,449
Amortization of debt discount and debt issuance costs	299	244
Gain on sale of Marshall Mine, LLC	0	(2,695)
Earnings from equity method investments	0	(1,100)
Other non-cash items, net	(55)	3
Changes in operating assets and liabilities:
Receivables and related party receivables	380	3,622
Prepaid expenses and other assets	1,036	2,213
Inventories, net	(1,493)	(4,946)
Other long-term assets, net	(1,089)	(2,886)
Accounts payable and accrued expenses	(1,821)	(10,114)
Other current liabilities	1,560	83
Operating lease liabilities	(786)	398
Other long-term liabilities	(926)	261
Net cash used in operating activities	(2,424)	(21,159)
Cash flows from investing activities
Acquisition of property, plant, equipment, and intangible assets, net	(28,766)	(10,383)
Acquisition of mine development costs	(85)	(1,247)
Cash and restricted cash acquired in business acquisition	0	2,225
Payment for disposal of Marshall Mine, LLC	0	(2,177)
Distributions from equity method investees in excess of cumulative earnings	0	1,100
Net cash used in investing activities	(28,851)	(10,482)
Cash flows from financing activities
Net proceeds from common stock issued in private placement transactions	14,951	15,220
Repurchase of common stock to satisfy tax withholdings	(599)	(160)
Principal payments on finance lease obligations	(565)	(577)
Principal payments on CTB Loan	(268)	(213)
Net proceeds from CFG Loan, related party, net of discount and issuance costs	0	8,522
Net cash provided by financing activities	14,319	22,792
Decrease in Cash and Restricted Cash	(16,956)	(8,849)
Cash and Restricted Cash, beginning of period	54,153	76,432
Cash and Restricted Cash, end of period	37,197	67,583
Supplemental disclosure of non-cash investing and financing activities:
Change in accrued purchases for property and equipment	4,013	328
Equity issued as consideration for acquisition of business	0	31,206
Paid-in-kind dividend on Series A Preferred Stock	0	157
Related Party
Cash flows from financing activities
Net proceeds from common stock issuance, related party	$ 800	$ 0