Other financial liabilities (Narrative) (Details)	12 Months Ended
Dec. 31, 2017 CAD ($)
Statement [Line Items]
Number of warrants granted in share-based payment arrangement	21,830,490
Weighted average exercise price of warrants granted in share-based payment arrangement	$ 15.00
Description of expected timing of outflows, contingent liabilities in business combination	The purchase price of the acquisition of New Britannia Mine and Mill contained an option (European) that pays the seller $5,000 if the price of gold is equal to or above $1,400/oz on May 4, 2018.

The description of the expected timing of outflows of economic benefits for contingent liabilities recognised in a business combination. [Refer: Contingent liabilities [member]; Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2017-01-01
-Paragraph B67
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2017-03-01&anchor=para_B67_c&doctype=Appendix&seq=2
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2017-01-01
-Paragraph B64
-Subparagraph j
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2017-03-01&anchor=para_B64_j&doctype=Appendix&seq=2
-URIDate 2017-03-09

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