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Segmented Information (Segment revenues and results) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Disclosure of operating segments [line items] |  |
Operating revenues | $ 748.1 | $ 683.1
Cost of sales |  |
Cost of sales | 312.6 | 339.0
Royalties | 10.2 | 17.4
COVID costs | 6.5 | 0.0
Amortization | 152.7 | 165.0
Cost of sales | 482.0 | 521.4
Expenses |  |
Exploration | 7.2 | 6.7
Corporate and administrative | 21.0 | 19.8
Share-based compensation | 10.3 | 9.2
EARNINGS FROM OPERATIONS | 227.6 | 126.0
Finance expense | (4.3) | (2.5)
Foreign exchange loss | (1.4) | 0.3
Other gain | (3.7) | 5.1
EARNINGS BEFORE INCOME TAXES | 218.2 | 128.9
Operating segments [member] | Young-Davidson [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 239.4 | 262.1
Cost of sales |  |
Cost of sales | 133.9 | 146.6
Royalties | 3.7 | 4.4
COVID costs | 0.0 |
Amortization | 63.7 | 80.1
Cost of sales | 201.3 | 231.1
Expenses |  |
Exploration | 0.0 | 0.0
Corporate and administrative | 0.0 | 0.0
Share-based compensation | 0.0 | 0.0
EARNINGS FROM OPERATIONS | 38.1 | 31.0
Operating segments [member] | Mulatos [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 261.7 | 194.4
Cost of sales |  |
Cost of sales | 120.9 | 107.8
Royalties | 1.3 | 3.1
COVID costs | 2.0 |
Amortization | 44.6 | 28.0
Cost of sales | 168.8 | 138.9
Expenses |  |
Exploration | 4.2 | 3.6
Corporate and administrative | 0.0 | 0.0
Share-based compensation | 0.0 | 0.0
EARNINGS FROM OPERATIONS | 88.7 | 51.9
Operating segments [member] | Island Gold [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 247.0 | 207.3
Cost of sales |  |
Cost of sales | 57.8 | 64.2
Royalties | 5.2 | 9.9
COVID costs | 4.5 |
Amortization | 44.4 | 55.3
Cost of sales | 111.9 | 129.4
Expenses |  |
Exploration | 1.0 | 1.1
Corporate and administrative | 0.0 |
Share-based compensation | 0.0 |
EARNINGS FROM OPERATIONS | 134.1 | 76.8
Operating segments [member] | El Chanate [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues |  | 19.3
Cost of sales |  |
Cost of sales |  | 20.4
Royalties |  | 0.0
Amortization |  | 1.6
Cost of sales |  | 22.0
Expenses |  |
Exploration |  | 0.0
Corporate and administrative |  | 0.0
Share-based compensation |  | 0.0
EARNINGS FROM OPERATIONS |  | (2.7)
Corporate and other [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 0.0 | 0.0
Cost of sales |  |
Cost of sales | 0.0 | 0.0
Royalties | 0.0 | 0.0
COVID costs | 0.0 |
Amortization | 0.0 | 0.0
Cost of sales | 0.0 | 0.0
Expenses |  |
Exploration | 2.0 | 2.0
Corporate and administrative | 21.0 | 19.8
Share-based compensation | 10.3 | 9.2
EARNINGS FROM OPERATIONS | $ (33.3) | $ (31.0)

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