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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Risks and Uncertainties (Details) - USD ($) $ in Thousands |  |  |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | ---
Mar. 02, 2022 | Jan. 29, 2021 | Dec. 31, 2020 | Sep. 10, 2020 | Mar. 31, 2022 | Dec. 31, 2021
Long-term debt |  |  |  |  | $ 63,553 | $ 48,866
Secured Debt |  |  |  |  |  |
Long-term debt |  |  |  |  | 50,000 |
Unsecured Debt |  |  |  |  |  |
Long-term debt |  |  |  |  | 15,000 |
Canadian Development Expenses | Los Azules Copper Project |  |  |  |  |  |
Long-term debt |  |  |  |  | 40,000 |
Canadian Development Expenses | Equity Financing In February 2021 |  |  |  |  |  |
Gross proceeds |  |  |  |  |  | 31,500
Canadian Development Expenses | Flow Through Common Shares |  |  |  |  |  |
Gross proceeds |  | $ 12,700 |  |  |  | $ 12,700
Canadian Exploration Expenditures | Flow Through Common Shares |  |  |  |  |  |
Gross proceeds | $ 15,100 |  | $ 9,800 | $ 10,400 | $ 15,100 |

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