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Summary of significant accounting policies - Schedule of Subsidiaries (Details)	12 Months Ended
	Dec. 31, 2018
Fekola
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	80.00%
Otjikoto
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	90.00%
Masbate
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	100.00%
Libertad
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	100.00%
Limon
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	100.00%
Kiaka
Disclosure of subsidiaries [line items]
Percentage of ownership interest in subsidiary	81.00%

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Subsidiaries [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2017-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
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-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2017-01-01
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2017-03-01&anchor=para_16_b_iii&doctype=Standard
-URIDate 2017-03-09

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph 19B
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_19B_c&doctype=Standard
-URIDate 2017-03-09

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