v3.25.4

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands | Dec. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Deferred income tax assets: |  |
Net operating loss and credit carryforwards | $ 48,386 | $ 48,804
Inventory | 0 | 8,670
Asset retirement obligations | 13,743 | 18,114
Black lung obligations | 7,580 | 7,793
Accrued expenses | 9,913 | 8,861
Other | 3,636 | 1,852
Total deferred income tax assets | 83,258 | 94,094
Less: valuation allowance for deferred income tax assets | (45,045) | (44,674)
Net deferred income tax assets | 38,213 | 49,420
Deferred income tax liabilities: |  |
Inventory | 211 | 0
Prepaid expenses | (11,123) | (10,930)
Property, plant and equipment | (71,580) | (98,283)
Investments in partnership | (5,675) | 0
Other | (856) | (832)
Total deferred income tax liabilities | (89,445) | (110,045)
Net deferred income tax liability | $ (51,232) | $ (60,625)

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