Note 15 - Income Taxes (Tables)

12 Months Ended

Jul. 31, 2020

Notes Tables

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

	Year Ended July 31,
	2020		2019		2018
Federal income tax provision rate	21.00	%	21.00	%	26.87	%
State income tax provision rate, net of federal income tax effect	0.72	%	0.52	%	0.59	%
Total income tax provision rate	21.72	%	21.52	%	27.46	%

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

	Year Ended July 31,
	2020			2019			2018
Loss before income taxes	$	(14,616,067	)	$	(17,167,161	)	$	(18,534,145	)
Corporate tax rate		21.72	%		21.52	%		27.46	%
Expected tax recovery		(3,174,610	)		(3,694,373	)		(5,089,476	)
Increase (decrease) resulting from
Foreign tax rate differences		85,796			90,391			167,162
Permanent differences		170,023			2,427,665			434,863
Prior year true-up		(435,565	)		(160,019	)		(141,814	)
Foreign exchange rate differences		17,456			39,667			(41,014	)
Other		71,805			(94,291	)		35,706
Recognition of deferred tax assets		-			-			430,121
Change in valuation allowance		3,233,427			1,373,462			4,156,768
Tax adjustment from operations		(31,668	)		(17,498	)		(47,684	)
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		26,117			3,126			3,137
Deferred tax benefits	$	(5,551	)	$	(14,372	)	$	(707,511	)

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

	Year Ended July 31,
	2020			2019			2018
United States	$	(13,962,287	)	$	(16,560,132	)	$	(17,709,866	)
Canada		53,960			120,362			145,267
Paraguay		(707,740	)		(727,391	)		(969,546	)
	$	(14,616,067	)	$	(17,167,161	)	$	(18,534,145	)

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

	July 31, 2020			July 31, 2019
Deferred tax assets (liabilities)
Mineral properties	$	1,270,292		$	1,256,327
Exploration costs		6,384,265			6,551,403
Stock option expense		4,594,159			4,570,905
Depreciable property		(1,157,934	)		(937,614	)
Inventories		(3,550,814	)		(3,343,361	)
Asset retirement obligations		62,626			20,561
Other		58,559			35,983
Section 163(j) interest expense carry forwards		733,343			384,109
Loss carry forwards		46,552,687			43,198,434
		54,947,183			51,736,747
Valuation allowance		(54,973,300	)		(51,739,873	)
Deferred tax assets		(26,117	)		(3,126	)
Deferred tax assets, other comprehensive loss		26,117			3,126
Deferred tax liabilities
Mineral properties		(545,000	)		(550,551	)
Net deferred tax liabilities	$	(545,000	)	$	(550,551	)

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
Remaining balance		156,594,095
	$	167,299,520

July 31, 2027	$	183,105
July 31, 2028		629,788
July 31, 2029		769,072
July 31, 2030		764,230
July 31, 2031		1,747,548
Remaining balance		958,124
	$	5,051,867