Supplemental Financial Information (Tables)

6 Months Ended

Jun. 30, 2026

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

The following table summarizes the components of Prepaid expenses and other current assets and Other long-term assets, net as presented in the Condensed Consolidated Balance Sheets:


	As of
(in thousands)	June 30, 2026		December 31, 2025 As Adjusted (1)








Prepaid expenses and other current assets:
Prepaid expenses	$	3,617	$	2,959
Prepaid lender fees, net (2)	1,418		1,472
Prepaid taxes and tax refunds	143		147
Other	1,716		1,826
Total prepaid expenses and other current assets	$	6,894	$	6,404

Other long-term assets, net:
Spare parts, net	$	11,015	$	11,017
Mine development costs, net	6,618		6,763
Right of use assets, operating leases, net	5,412		6,793
Upfront Customer Consideration (3)	5,279		5,639
Deferred plant turnaround costs, net (4)	2,369		394
Mine reclamation asset, net	1,581		1,645
Intangible assets, net	572		570
Other	2,654		2,680

Total other long-term assets, net	$	35,500	$	35,501

(1) Adjusted to reflect the retrospective change in accounting method for planned major maintenance costs as described in Note 1. See Note 12 for reconciliation to previously reported amounts.

(2) Represents legal and administrative costs incurred to obtain the Revolving Credit Facility. This asset is being amortized on a straight-line basis over the five-year contractual period of the Revolving Credit Facility.

(3) Represents remaining balance on consideration paid to a customer under a long-term supply contract executed in 2020. This asset is being amortized as a reduction to revenue on a straight-line basis over the expected 15-year contractual period of the contract.

(4) Represents costs incurred in connection with planned major maintenance activities, which currently includes maintenance materials, parts and direct labor directly attributable to the Company's plant turnaround in April 2026 for the period ended June 30, 2026, and the trailing deferred plant turnaround costs, net directly attributable to the Company's plant turnaround in April 2024 for the period ended December 31, 2025 (as adjusted). This asset is being amortized on a straight-line basis over the expected two-year period until the Company's next planned turnaround event.

Schedule of Other Liabilities

The following table details the components of Other current liabilities and Other long-term liabilities as presented in the Condensed Consolidated Balance Sheets:


	As of
(in thousands)	June 30, 2026		December 31, 2025
Other current liabilities:
Current portion of operating lease obligations	$	2,654	$	2,842
Sales, use and other taxes payable	1,282		1,304
Current portion of mine reclamation liability	1,037		1,037



Other	3,095		1,832
Total other current liabilities	$	8,068	$	7,015

Other long-term liabilities:
Mine reclamation liabilities	$	5,901	$	5,719
Operating lease obligations, long-term	4,705		6,086



Other	—		63
Total other long-term liabilities	$	10,606	$	11,868

Schedule of Change in Asset Retirement Obligation

The Mine reclamation liabilities represent AROs. Changes in the AROs were as follows:


	As of
(in thousands)	June 30, 2026		December 31, 2025
Asset retirement obligations, beginning of period	$	6,756	$	6,279

Accretion	280		513
Liabilities settled	(98)		(177)
Changes due to scope and timing of reclamation	—		141
Asset retirement obligations, end of period	6,938		6,756
Less current portion	1,037		1,037
Asset retirement obligations, long-term	$	5,901	$	5,719