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MINING INTERESTS (Details 1) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | $ 3,200.4 | $ 3,191.3 | [1]
New Afton [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 785.5 | 846.7 |
Mesquite [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 236.2 | 271.6 |
Peak Mines [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 121.2 |
Cerro San Pedro [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.6 | 2.0 |
Rainy River [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 1,621.4 | 1,373.4 |
Blackwater [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 552.1 | 539.5 |
El Morro gold stream asset [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 32.0 |
Other [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment | [2] | 4.6 | 4.9 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 560.9 | 1,117.1 | [1]
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | New Afton [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 22.9 | 20.0 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Mesquite [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Peak Mines [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 9.8 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Cerro San Pedro [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Rainy River [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.5 | 531.0 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Blackwater [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 537.5 | 524.3 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | El Morro gold stream asset [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 32.0 |
Mining Properties Non-depletable Including Exploration and Evaluation [Member] | Other [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment | [2] | 1.1 | 1.1 |
Plant and Equipment [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 965.7 | 526.4 | [1]
Plant and Equipment [Member] | New Afton [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 225.7 | 247.1 |
Plant and Equipment [Member] | Mesquite [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 83.5 | 98.2 |
Plant and Equipment [Member] | Peak Mines [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 52.5 |
Plant and Equipment [Member] | Cerro San Pedro [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Plant and Equipment [Member] | Rainy River [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 633.6 | 109.6 |
Plant and Equipment [Member] | Blackwater [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 14.6 | 15.2 |
Plant and Equipment [Member] | El Morro gold stream asset [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 0.0 |
Plant and Equipment [Member] | Other [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment | [2] | 3.5 | 3.8 |
Construction in progress [member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 57.0 | 741.4 | [1]
Construction in progress [member] | New Afton [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 15.1 | 5.2 |
Construction in progress [member] | Mesquite [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 2.7 | 3.1 |
Construction in progress [member] | Peak Mines [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 0.3 |
Construction in progress [member] | Cerro San Pedro [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Construction in progress [member] | Rainy River [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 39.2 | 732.8 |
Construction in progress [member] | Blackwater [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Construction in progress [member] | El Morro gold stream asset [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 0.0 |
Construction in progress [member] | Other [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment | [2] | 0.0 | 0.0 |
Mining Properties Depletable [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 1,620.5 | 805.3 | [1]
Mining Properties Depletable [Member] | New Afton [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 521.8 | 574.4 |
Mining Properties Depletable [Member] | Mesquite [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 150.0 | 170.3 |
Mining Properties Depletable [Member] | Peak Mines [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 58.6 |
Mining Properties Depletable [Member] | Cerro San Pedro [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.6 | 2.0 |
Mining Properties Depletable [Member] | Rainy River [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 948.1 | 0.0 |
Mining Properties Depletable [Member] | Blackwater [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  | 0.0 | 0.0 |
Mining Properties Depletable [Member] | El Morro gold stream asset [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment |  |  | 0.0 |
Mining Properties Depletable [Member] | Other [Member] |  |  |  |
Mining Interests [Line Items] |  |  |  |
Property, plant and equipment | [2] | $ 0.0 | $ 0.0 |
[1] | Prior-year period comparatives have been revised as per note 5.
[2] | Other includes corporate balances and exploration properties.

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- Definition The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 16 -IssueDate 2017-01-01 -Paragraph 73 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=16&date=2017-03-01&anchor=para_73_e&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 54 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_54_a&doctype=Standard -URIDate 2017-03-09 + Details
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