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FINANCIAL RISK MANAGEMENT (Details 5) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
Gold price |  |
Financial risk management [Line Items] |  |
Impact on net earnings due to 10 % change in price | $ 52.5 | $ 47.4
Impact on other comprehensive income due to 10 % change in price | 0.0 | 0.0
Copper price |  |
Financial risk management [Line Items] |  |
Impact on net earnings due to 10 % change in price | 9.0 | 22.1
Impact on other comprehensive income due to 10 % change in price | 0.0 | 0.0
Silver price |  |
Financial risk management [Line Items] |  |
Impact on net earnings due to 10 % change in price | 1.1 | 1.4
Impact on other comprehensive income due to 10 % change in price | 0.0 | 0.0
Fuel price |  |
Financial risk management [Line Items] |  |
Impact on net earnings due to 10 % change in price | 4.6 | 3.5
Impact on other comprehensive income due to 10 % change in price | $ 0.3 | $ 0.1

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