Income taxes

12 Months Ended

Dec. 31, 2025

Income Tax Disclosure [Abstract]

Income taxes

Income taxes

For the years ended December 31, 2025 and 2024, the Company recorded no income tax benefit or expense. The annual effective tax rate was nil for 2025 and 2024, which was driven primarily by losses for each period.

The Company is also subject to mining taxes in Nevada, which are classified as income taxes as such taxes are based on a percentage of mining profits, but did not incur any mining tax expense due to cessation of mining operations. The Company is not subject to foreign income taxes as all of the Company’s operations and properties are located within the United States.

The Company’s loss before income taxes was attributable solely to domestic activities in the United States. The components of the Company’s income tax expense (benefit) were as follows (in thousands):

	Year Ended December 31,
	2025		2024
Current
Federal	$	—	$	—
Deferred
Federal	(8,170)		(13,786)
Change in Valuation Allowance	8,170		13,786
Income tax expense (benefit)	$	—	$	—

For the year ended December 31, 2025, and the year ended December 31, 2024, the Company incurred no net income tax expense (benefit).

The following table provides a reconciliation of income taxes computed at the United States federal statutory tax rate of 21% in 2025 and 2024 to the income tax provision (dollars in thousands):

	Year Ended December 31,
	2025		2024
Loss before income taxes	$	(40,664)	$	(60,896)
United States statutory income tax rate	21%		21%
Income tax benefit at United States statutory income tax rate	(8,540)		(12,788)
Change in valuation allowance	8,170		13,786
Warrant fair value adjustment	(1)		—
Adjustment of prior year income taxes	264		(1,067)
Nondeductible expenses	107		69
Income tax expense (benefit)	$	—	$	—

For the year ended December 31, 2025, the effective tax rate was a result of an increase in the valuation allowance of $8.2 million.

For the year ended December 31, 2024, the effective tax rate was a result of an increase in the valuation allowance of $13.8 million and adjustment to prior year income taxes.

The components of the Company’s deferred tax assets are as follows (in thousands):

	Year Ended December 31,
	2025		2024
Net operating loss	$	80,863	$	74,056
Mineral properties	56,198		52,303
Plant, equipment, and mine development	1,687		1,415
Intangible assets	14,181		15,687
Deferred gain on sale of royalty	6,266		6,266
Asset retirement obligation	2,472		2,762
Interest expense carryforward	8,799		9,156
Accrued compensation	663		629
Stock-based compensation	1,927		1,998
Inventories	943		947
Assets held-for-sale	(39)		476
Other	895		990
Valuation allowance	(174,855)		(166,685)
Total	$	—	$	—

Based on the weight of evidence available as of both December 31, 2025 and 2024, which included recent operating results, future projections, and historical inability to generate positive operating cash flow, the Company concluded that it was more likely than not that the benefit of its net deferred tax assets would not be realized and, as such, recorded full valuation allowances of $174.9 million and $166.7 million, respectively, against its net deferred tax assets.

The Company had tax loss carryovers as of December 31, 2025 and 2024, of $385.1 million and $352.6 million, respectively, for federal income tax purposes. The carryover amount as of December 31, 2025, can be carried forward indefinitely and can be used to offset taxable income and reduce income taxes payable in future periods, subject to limitations under Section 382. Section 382 of the Internal Revenue Code imposes limitations on the use of U.S. federal net operating losses and other unrealized losses upon a more than 50% change in ownership in the Company within a three-year period. In connection with multiple equity offerings during 2022 and 2025, the Company underwent the following Section 382 ownership changes (in thousands):

Tax Loss Carryovers		Year Ended December 31,
Ownership Change Date	Annual Limitation	2025		2024
March 25, 2022	$1,300	$	306,830	$	299,743
June 13, 2025	3,066	64,332		N/A
October 9, 2025	7,229	7,620		N/A

As a result, utilization of the Company’s above net operating losses and other unrealized losses are limited on an annual basis. If the Section 382 annual limitation amount is not fully utilized in a particular tax year, then the unused portion from that tax year increases the Section 382 annual limitation in the subsequent year and/or subsequent years.

As necessary, the Company provides a reserve against the benefits of uncertain tax positions taken in its tax filings that are more likely than not to not be sustained upon examination. Based on the weight of available evidence, the Company does not believe it has taken any uncertain tax positions that require the establishment of a reserve. The Company has not recorded any

income tax reserves or related interest, or penalties related to income tax liabilities as of December 31, 2025. The Company's policy, if it were to have uncertain tax positions, is to recognize interest and/or penalties related to unrecognized tax benefits as part of its income tax expense. With limited exception, the Company is no longer subject to U.S. federal and state income tax audits by taxing authorities for tax years 2019 and prior; however, tax loss operating loss and credit carryovers from all years are subject to examinations and adjustments for at least three years following the year in which the attributes are utilized.