Derivative instruments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
DERIVATIVE LIABILITIES
Total derivative assets (liabilities)	$ 0.9	$ (0.9)
Foreign exchange forward contracts
DERIVATIVE LIABILITIES
Total derivative assets (liabilities)	1.5	0.0
Unsettled provisionally priced concentrate derivatives, and swap contracts
DERIVATIVE LIABILITIES
Total derivative assets (liabilities)	$ (0.6)	$ (0.9)

The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_55&doctype=Standard
-URIDate 2021-03-24

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant