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Note 11 - Self-Insurance (Details Textual) $ in Thousands | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | ---
Operating Lease, Liability, Total | $ 712 | $ 230
Restricted Cash and Cash Equivalents, Total | 4,281 | 3,417
Future Workers' Compensation Claim Payments [Member] |  |
Restricted Cash and Cash Equivalents, Total | $ 4,300 | 3,400
Mining Properties and Mineral Rights [Member] |  |
Number of Mining Units | 7 |
Geographic Spread of Mining Units, in Miles | 11 |
Operating Lease, Liability, Total | $ 262,000 | $ 280,000

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