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DERIVATIVE INSTRUMENTS (Details 2) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
GAIN (loss) on the provisional pricing of concentrate sales |  |
Realized | $ 11.9 | $ 9.6
Unrealized | 4.2 | 4.5
Total gains | 16.1 | 14.1
Gold [Member] |  |
GAIN (loss) on the provisional pricing of concentrate sales |  |
Realized | 1.9 | 2.8
Unrealized | 0.1 | (1.5)
Total gains | 2.0 | 1.3
Copper [Member] |  |
GAIN (loss) on the provisional pricing of concentrate sales |  |
Realized | 10.0 | 6.8
Unrealized | 4.1 | 6.0
Total gains | $ 14.1 | $ 12.8

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- Definition The gains (losses) on the provisionally pricing of concentrate sales which realised during the reporting period. + References No definition available. + Details
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- Definition Totals gains (losses) on the provisionally pricing of concentrate sales which recognised during the reporting period. + References No definition available. + Details
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- Definition The gains (losses) on the provisionally pricing of concentrate sales which recognised as unrealised during the reporting period. + References No definition available. + Details
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