INCOME TAXES (Tables)

12 Months Ended

Jul. 31, 2017

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

A reconciliation of income tax computed at the federal and state statutory tax rates including the Company’s effective tax rate is as follows:

	Year Ended July 31,
	2017			2016			2015
Federal income tax provision rate		35.00	%		35.00	%		35.00	%
State income tax provision rate, net of federal income tax effect		0.43	%		0.35	%		0.32	%
Total income tax provision rate		35.43	%		35.35	%		35.32	%

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The actual income tax provisions differ from the expected amounts calculated by applying the combined federal and state corporate income tax rates to the Company’s loss before income taxes. The components of these differences are as follows:

	Year Ended July 31,
	2017			2016			2015
Loss before income taxes	$	(18,005,411)		$	(17,362,111)		$	(23,397,341)
Corporate tax rate		35.43	%		35.35	%		35.32	%
Expected tax recovery		(6,379,317)			(6,137,506)			(8,263,941)
Increase (decrease) resulting from
Foreign tax rate differences		185,700			230,148			223,980
Permanent differences		446,377			806,736			1,473,225
Prior year true-up		(804,822)			(647,307)			50,025
State tax rate true-up		(223,770)			(105,843)			(205,285)
Property acquisition		(491,798)			-			-
Foreign exchange rate differences		(3,248)			129,015			144,242
Other		81,660			59,705			62,398
Change in valuation allowance		7,149,654			5,627,606			6,474,775
Tax adjustment from operations		(39,564)			(37,446)			(40,581)
Unrealized loss, other comprehensive loss		5,209			5,207			5,168
Deferred income tax benefit		(34,355)		$	(32,239)		$	(35,413)

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

The components of income (loss) from operations before income taxes, by tax jurisdiction, are as follows:

	Year Ended July 31,
	2017		2016		2015
United States	$	(17,303,682)	$	(16,488,447)	$	(22,612,974)
Canada		45,316		54,216		158,616
Paraguay	$	(747,045)		(927,880)		(942,983)
		(18,005,411)	$	(17,362,111)	$	(23,397,341)

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The Company’s deferred tax assets (liabilities) are as follows:

	July 31, 2017		July 31, 2016
Deferred tax assets (liabilities)
Mineral property acquisitions	$	2,533,819	$	1,917,796
Exploration costs		10,950,241		10,648,043
Stock option expense		7,031,732		7,081,853
Depreciable property		(367,164)		(66,912)
Inventories		(5,471,486)		(3,632,178)
Asset retirement obligations		(130,740)		(220,209)
Other		179,518		271,468
Loss carry forward		57,989,069		49,565,476
		72,714,989		65,565,337
Valuation allowance		(72,720,198)		(65,570,544)
Deferred tax assets		(5,209)		(5,207)
Deferred tax assets, other comprehensive loss		5,209		5,207
Deferred tax liabilities
Mineral property acquisition		(609,470)		(643,825)
Net deferred tax liabilities	$	(609,470)	$	(643,825)

UNITED STATES

Summary of Operating Loss Carryforwards [Table Text Block]

The Company’s U.S. net operating loss carry-forwards expire as follows:

July 31, 2023	$	180,892
July 31, 2024		228,757
July 31, 2025		507,833
July 31, 2026		5,895,221
July 31, 2027		3,892,722
July 31, 2028		9,913,533
July 31, 2029		8,469,032
July 31, 2030		7,319,644
July 31, 2031		14,420,187
July 31, 2032		15,014,013
July 31, 2033		16,332,007
July 31, 2034		21,605,546
July 31, 2035		19,357,683
July 31, 2036		18,490,648
July 31, 2037		19,087,066
	$	160,714,784

CANADA

Summary of Operating Loss Carryforwards [Table Text Block]

The Company’s Canadian net operating loss carry-forwards in Canadian dollars expire as follows:

July 31, 2027	$	183,105
July 31, 2028		629,788
July 31, 2029		769,072
July 31, 2030		1,035,403
July 31, 2031		2,210,551
July 31, 2032		761,843
July 31, 2033		69,854
July 31, 2034		61,769
July 31, 2035		41,173
July 31, 2036		9,917
	$	5,772,475