XML 133 R116.htm IDEA: XBRL DOCUMENT v3.20.1
FAIR VALUE MEASUREMENT - Summary of financial assets and liabilities by category (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Long-term debts [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value $ 707.7 $ 652.9
Gold stream obligation [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 164.5 182.4
Cash and cash equivalents    
FINANCIAL ASSETS    
Financial assets, at fair value 83.4 103.7
Trade and other receivables [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 14.5 36.6
Investment [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 0.5 0.8
Proceeds due from income tax refunds at Mesquite [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 9.0 8.5
Deferred share units [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 1.1 0.3
Financial liabilities at amortised cost, category [member] | Long-term debts [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 714.5 780.5
Financial liabilities at amortised cost, category [member] | Trade and other receivables [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 111.3 101.3
Financial liabilities at fair value through profit or loss, category [member] | Level 1 of fair value hierarchy [member] | Restricted share units [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 0.5 0.3
Financial liabilities at fair value through profit or loss, category [member] | Level 1 of fair value hierarchy [member] | Deferred share units [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 0.0 0.3
Financial liabilities at fair value through profit or loss, category [member] | Level 2 of fair value hierarchy [member] | Gold price option contracts [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 26.4 4.8
Financial liabilities at fair value through profit or loss, category [member] | Level 3 of fair value hierarchy [member] | Gold stream obligation [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 164.5 182.4
Financial liabilities at fair value through profit or loss, category [member] | Level 3 of fair value hierarchy [member] | Performance Share Units [Member]    
FINANCIAL LIABILITIES    
Financial liabilities, at fair value 0.2 0.2
Financial assets at amortised cost, category [member] | Cash and cash equivalents    
FINANCIAL ASSETS    
Financial assets, at fair value 83.4 103.7
Financial assets at amortised cost, category [member] | Trade and other receivables [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 14.5 36.6
Financial assets at amortised cost, category [member] | Level 3 of fair value hierarchy [member] | Proceeds due from income tax refunds at Mesquite [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 9.0 8.5
Financial assets at fair value through profit or loss, category [member] | Level 1 of fair value hierarchy [member] | Investment [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 0.5 0.8
Financial assets at fair value through profit or loss, category [member] | Level 2 of fair value hierarchy [member] | Provisionally priced contracts [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value 1.5 (1.6)
Financial assets at fair value through profit or loss, category [member] | Level 2 of fair value hierarchy [member] | Gold and copper swap contracts [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value (1.3) 0.9
Financial assets at fair value through profit or loss, category [member] | Level 2 of fair value hierarchy [member] | Copper price option contracts [Member]    
FINANCIAL ASSETS    
Financial assets, at fair value $ 0.0 $ 0.7