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Segmented Information (Segment revenues and results) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Disclosure of operating segments [line items] |  |
Operating revenues | $ 542.8 | $ 482.2
Cost of sales |  |
Cost of sales | 315.6 | 297.0
Royalties | 15.6 | 13.3
Amortization | 125.6 |
Cost of sales | 456.8 | 429.3
Expenses |  |
Exploration | 8.3 | 5.1
Corporate and administrative | 15.5 | 16.3
Share-based compensation | 6.2 |
EARNINGS FROM OPERATIONS | 56.0 | 21.3
Finance expense | (9.1) | (24.0)
Foreign exchange loss | 5.0 | (12.5)
Other gains (loss) | (0.6) | 7.6
Loss on redemption of senior secured notes | (29.1) | 0.0
EARNINGS (LOSS) BEFORE INCOME TAXES | 22.2 | (7.6)
Operating segments [member] | Young-Davidson [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 249.7 | 211.9
Cost of sales |  |
Cost of sales | 125.9 | 107.4
Royalties | 4.4 | 3.7
Amortization | 83.1 | 72.6
Cost of sales | 213.4 | 183.7
Expenses |  |
Exploration | 0.0 | 0.0
Corporate and administrative | 0.0 | 0.0
Share-based compensation | 0.0 | 0.0
EARNINGS FROM OPERATIONS | 36.3 | 28.2
Operating segments [member] | Mulatos [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 201.4 | 187.3
Cost of sales |  |
Cost of sales | 112.9 | 117.2
Royalties | 10.6 | 9.6
Amortization | 29.5 | 37.8
Cost of sales | 153.0 | 164.6
Expenses |  |
Exploration | 6.7 | 2.0
Corporate and administrative | 0.0 | 0.0
Share-based compensation | 0.0 | 0.0
EARNINGS FROM OPERATIONS | 41.7 | 20.7
Operating segments [member] | Island Gold [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 14.9 | 83.0
Cost of sales |  |
Cost of sales | 4.1 | 72.4
Royalties | 0.6 | 0.0
Amortization | 8.7 | 8.6
Cost of sales | 13.4 | 81.0
Expenses |  |
Exploration | 0.0 | 0.0
Corporate and administrative | 0.0 | 0.0
Share-based compensation | 0.0 | 0.0
EARNINGS FROM OPERATIONS | 1.5 | 2.0
Operating segments [member] | El Chanate [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 76.8 | 0.0
Cost of sales |  |
Cost of sales | 72.7 | 0.0
Royalties | 0.0 | 0.0
Amortization | 4.3 | 0.0
Cost of sales | 77.0 | 0.0
Expenses |  |
Exploration | 0.0 | 3.1
Corporate and administrative | 0.0 | 16.3
Share-based compensation | 0.0 | 10.2
EARNINGS FROM OPERATIONS | (0.2) | (29.6)
Corporate and other [Member] |  |
Disclosure of operating segments [line items] |  |
Operating revenues | 0.0 | 482.2
Cost of sales |  |
Cost of sales | 0.0 | 297.0
Royalties | 0.0 | 13.3
Amortization | 0.0 | 119.0
Cost of sales | 0.0 | 429.3
Expenses |  |
Exploration | 1.6 | 5.1
Corporate and administrative | 15.5 | 16.3
Share-based compensation | 6.2 | 10.2
EARNINGS FROM OPERATIONS | $ (23.3) | $ 21.3

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