Mineral properties - Additional Information (Detail)					1 Months Ended	6 Months Ended	1 Months Ended
	Jun. 30, 2012 CAD	Dec. 31, 2011 CAD	Dec. 31, 2011 Spring Valley USD ($)	Dec. 31, 2011 Spring Valley CAD	Jun. 30, 2012 Tonopah CAD	Jun. 30, 2012 Tonopah USD ($)	Jun. 30, 2012 Tonopah Minimum	Jun. 30, 2012 Tonopah Maximum	Jan. 31, 2012 Pan USD ($)	Jan. 31, 2012 Pan CAD	Apr. 30, 2007 Pan Ounce	Jan. 31, 2012 Pan Minimum USD ($)	Apr. 30, 2007 Pan Minimum USD ($)	Apr. 30, 2007 Pan Maximum	Jan. 31, 2012 Gold Rock USD ($)	Jan. 31, 2012 Gold Rock CAD	Apr. 30, 2007 Gold Rock Ounce	Apr. 30, 2007 Gold Rock Minimum USD ($)	Apr. 30, 2007 Gold Rock Maximum	Aug. 31, 2008 Golden Eagle	Aug. 31, 2008 Golden Eagle Kinross USD ($)	Aug. 31, 2008 Golden Eagle Kinross CAD	Aug. 31, 2008 Golden Eagle HeclaLimited USD ($)	Aug. 31, 2008 Golden Eagle HeclaLimited CAD
Property, Plant and Equipment [Line Items]
Percentage of ownership interests acquired					100.00%	100.00%					100.00%						100.00%
Percentage of royalty from production							2.00%	7.00%					2.50%	4.00%				2.50%	4.00%
Minimum royalty from commercial production					305,430	$ 300,000
Royalty payment date					--08-15
Amounts receivable for recoverable salaries and expenses	48,088	31,866	6,428	6,537
Description of royalty payable											The Company must pay an advance minimum royalty of the greater of US$60,000 or the US dollar equivalent of 174 ounces of gold valued by the average of the London afternoon fixing for the third calendar quarter proceeding January 1 of the year in which the payment is due. The minimum advance royalties will be creditable against a sliding scale NSR production royalty of between 2.5% and 4%.						Annually the Company must pay an advance minimum royalty of the greater of US$60,000 or the US dollar equivalent of 108.05 ounces of gold valued by the average of the London afternoon fixing for the third calendar quarter preceding January 1 of the year in which the payment is due. The minimum advance royalties will be creditable against a sliding scale NSR production royalty of between 2.5% and 4%.
Advance minimum royalty payment													60,000					60,000
Ounces of gold											174						108.05
Royalty payment									296,169	295,428					183,914	183,454
Minimum requirement for expenditures during the term of the mining lease												65,000			75,000
Percentage of interest on business acquired																					75.00%	75.00%	25.00%	25.00%
Acquisition cost of business acquired																					$ 1,500,000	1,537,950	$ 483,333	500,200
Royalty percentage																				2.00%