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Other (Loss) Gain (Details) - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Apr. 01, 2019 | Dec. 31, 2019 | Dec. 31, 2018
Other Gain (Loss) [Abstract] |  |  |
Reduction of obligation to renounce flow-through exploration expenditures |  | $ 0.6 | $ 0.6
Unrealized gains on non-hedged derivatives |  | (0.6) | (0.4)
Loss on disposal of assets |  | (0.7) | (6.1)
Gain on Sale of non-core royalties | $ (8.0) | (8.0) | 0.0
Other |  | (2.2) | (2.5)
Other gains (losses) |  | 5.1 | (8.4)
Metalla common shares acquired | 8,239,698 |  |
Proceeds from issuance of flow-through shares | $ 8.0 | $ 7.5 | $ 0.0

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