Note 15 - Income Taxes (Tables)

12 Months Ended

Jul. 31, 2019

Notes Tables

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

	Year Ended July 31,
	2019			2018			2017
Federal income tax provision rate		21.00	%		26.87	%		35.00	%
State income tax provision rate, net of federal income tax effect		0.52	%		0.59	%		0.43	%
Total income tax provision rate		21.52	%		27.46	%		35.43	%

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

	Year Ended July 31,
	2019			2018			2017
Loss before income taxes	$	(17,167,161	)	$	(18,534,145	)	$	(18,005,411	)
Corporate tax rate		21.52	%		27.46	%		35.43	%
Expected tax recovery		(3,694,373	)		(5,089,476	)		(6,379,317	)
Increase (decrease) resulting from
Foreign tax rate differences		90,391			167,162			185,700
Permanent differences		2,427,665			434,863			446,377
Prior year true-up		(160,019	)		(141,814	)		(1,028,592	)
Property acquisition		-			-			(491,798	)
Foreign exchange rate differences		39,667			(41,014	)		(3,248	)
Other		(94,291	)		35,706			81,660
Recognition of deferred tax assets		-			430,121			-
Change in valuation allowance		1,373,462			4,156,768			7,149,654
Tax adjustment from operations		(17,498	)		(47,684	)		(39,564	)
Re-measurement of deferred tax liability at 21%		-			(232,843	)		-
Recognition of deferred tax assets to offset deferred tax liability		-			(430,121	)		-
Unrealized loss, other comprehensive loss		3,126			3,137			5,209
Deferred tax benefits	$	(14,372	)	$	(707,511	)	$	(34,355	)

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

	Year Ended July 31,
	2019			2018			2017
United States	$	(16,560,132	)	$	(17,709,866	)	$	(17,303,682	)
Canada		120,362			145,267			45,316
Paraguay		(727,391	)		(969,546	)		(747,045	)
	$	(17,167,161	)	$	(18,534,145	)	$	(18,005,411	)

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

	July 31, 2019			July 31, 2018
Deferred tax assets (liabilities)
Mineral properties	$	1,256,327		$	1,587,220
Exploration costs		6,551,403			6,556,355
Stock option expense		4,570,905			4,266,067
Depreciable property		(937,614	)		(255,544	)
Inventories		(3,343,361	)		(3,894,552	)
Asset retirement obligations		20,561			(28,925	)
Other		35,983			57,060
Section 163(j) interest expense carry forwards		384,109			-
Loss carry forward		43,198,434			42,075,593
		51,736,747			50,363,274
Valuation allowance		(51,739,873	)		(50,366,411	)
Deferred tax assets		(3,126	)		(3,137	)
Deferred tax assets, other comprehensive loss		3,126			3,137
Deferred tax liabilities
Mineral properties		(550,551	)		(564,923	)
Net deferred tax liabilities	$	(550,551	)	$	(564,923	)

Summary of Operating Loss Carryforwards [Table Text Block]

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		14,954,064
July 31, 2032		15,547,890
July 31, 2033		16,865,884
July 31, 2034		22,139,423
July 31, 2035		19,891,560
July 31, 2036		19,024,525
July 31, 2037		20,396,629
July 31, 2038		690,637
July 31, 2039		690,637
	$	166,608,883

July 31, 2027	$	183,105
July 31, 2028		629,788
July 31, 2029		769,072
July 31, 2030		764,230
July 31, 2031		1,914,943
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
July 31, 2037		-
July 31, 2038		6,511
July 31, 2039		29,176
	$	5,241,381