Basis of preparation (Narrative) (Details)	Apr. 25, 2019
United Copper And Moly L L C [Member] \| Rosemont Project [Member]
Basis Of Presentation [Line Items]
Percentage of voting equity interests acquired	7.95%

The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2019-01-01
-Paragraph B64
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2019-en-r&anchor=para_B64_c&doctype=Appendix&subtype=B
-URIDate 2019-03-27

Name:	ifrs-full_PercentageOfVotingEquityInterestsAcquired
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant