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ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS (Details) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2024 | Dec. 31, 2023
Unusual Risk or Uncertainty [Line Items] |  |
Asset retirement obligation, current | $ 0.2 | $ 0.2
Estimated undiscounted cash flows, to satisfy obligation | $ 52.5 | 50.2
Remediation term | 23 years |
Discount rate | 2.93% |
Environmental obligations, undiscounted cost | $ 26.3 | 26.7
Environmental obligations, current | 0.5 | 0.5
Closure and reclamation obligations, financial assurances | $ 45.5 | $ 45.4
Minimum |  |
Unusual Risk or Uncertainty [Line Items] |  |
Asset retirement obligations, credit-adjusted risk free rate | 6.50% |
Maximum |  |
Unusual Risk or Uncertainty [Line Items] |  |
Asset retirement obligations, credit-adjusted risk free rate | 12.00% |

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- Definition Rate applied to the undiscounted amount of environmental loss contingencies to arrive at the present value recorded as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481931/410-30-50-7 + Details
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- Definition Undiscounted amount of the accrual for environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481931/410-30-50-7 + Details
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