Inventory (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Disclosure of inventories [Abstract]
Mining and processing costs, inventories	$ 319.9	$ 345.4
Amortization	152.7	165.0
Amortization costs, Inventories		$ 165.0
Indirect Production Costs	5.4
Reclassified Amortization Costs	$ 1.1

The amount of amortisation expense. Amortisation is the systematic allocation of depreciable amounts of intangible assets over their useful lives.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 112
-Subparagraph c
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-URIDate 2020-01-01

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