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Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) oz | Dec. 31, 2019 USD ($)
Restricted Cash and Cash Equivalents, Noncurrent, Total |  | $ 1,053 | $ 1,053 |
Capitalized Drilling Costs |  | 5,200 | 4,400 | $ 14,400
Foreign Currency Transaction Gain (Loss), Realized |  | $ 417 | $ (4,605) | $ (8,236)
Minimum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 3 years |  |
Maximum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 14 years |  |
Casa Berardi [Member] |  |  |  |
Decrease in Expected Gold Production Due to Suspension (Ounce) | oz |  |  | 11,700 |
Suspension Costs |  |  | $ 1,600 |
Pandemic Related Procedures Costs |  | $ 2,400 |  |
San Sebastian [Member] |  |  |  |
Suspension Costs |  |  | 1,800 |
Greens Creek [Member] |  |  |  |
Suspension Costs from Quarantining Employee Per Week |  | $ 1,000 | $ 2,300 |
Percentage of Increase (Decrease) in Silver Production | (30.00%) |  |  |

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