Note 17 - Segmented Information - Operating Results by Geographic Segments (Details) - USD ($)	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Mineral Property Expenditures	$ 4,487,537	$ 4,552,151	$ 4,120,388
General and administrative	10,142,035	11,407,206	10,241,681
Depreciation, amortization and accretion	347,441	354,624	497,728
	14,977,013	16,313,981	15,218,433
Loss from operations	(14,977,013)	(16,313,981)	(15,218,433)
Other income (expenses)	(2,190,148)	(2,220,164)	(2,786,978)
Loss before income taxes	(17,167,161)	(18,534,145)	(18,005,411)
Impairment loss on mineral properties			297,942
Inventory write-down			60,694
United States Texas [Member]
Mineral Property Expenditures	3,072,855	2,381,993	2,450,834
General and administrative	6,619,855	7,055,370	7,053,270
Depreciation, amortization and accretion	314,599	325,567	487,288
	10,007,309	9,762,930	10,238,028
Loss from operations	(10,007,309)	(9,762,930)	(10,238,028)
Other income (expenses)	(3,337,331)	(2,630,691)	(2,772,617)
Loss before income taxes	(13,344,640)	(12,393,621)	(13,010,645)
Impairment loss on mineral properties			185,942
Inventory write-down			60,694
United States Arizona [Member]
Mineral Property Expenditures	112,724	100,296	101,628
General and administrative	14,040	13,877	33,761
Depreciation, amortization and accretion
	126,764	114,173	143,723
Loss from operations	(126,764)	(114,173)	(143,723)
Other income (expenses)	(18,914)	(18,914)	(18,914)
Loss before income taxes	(145,678)	(133,087)	(162,637)
Impairment loss on mineral properties			8,334
Inventory write-down
United States Wyoming [Member]
Mineral Property Expenditures	655,807	1,282,164
General and administrative	147,648	581,277
Depreciation, amortization and accretion	14,876	12,847
	818,331	1,876,288
Loss from operations	(818,331)	(1,876,288)
Other income (expenses)	2,284	1,541
Loss before income taxes	(816,047)	(1,874,747)
Impairment loss on mineral properties
Inventory write-down
United States Other States [Member]
Mineral Property Expenditures	69,910	67,550	70,588
General and administrative	3,557	10,931	3,933
Depreciation, amortization and accretion	996	996	996
	74,463	79,477	179,183
Loss from operations	(74,463)	(79,477)	(179,183)
Other income (expenses)	1,578,864
Loss before income taxes	1,504,401	(79,477)	(179,183)
Impairment loss on mineral properties			103,666
Inventory write-down
CANADA
Mineral Property Expenditures	16,078
General and administrative	3,165,883	3,467,934	3,063,839
Depreciation, amortization and accretion	11,666	11,599	8,088
	3,193,627	3,479,533	3,071,927
Loss from operations	(3,193,627)	(3,479,533)	(3,071,927)
Other income (expenses)	(432,598)	423,657	636
Loss before income taxes	(3,626,225)	(3,055,876)	(3,071,291)
Impairment loss on mineral properties
Inventory write-down
PARAGUAY
Mineral Property Expenditures	560,163	720,148	1,497,338
General and administrative	191,052	277,817	86,878
Depreciation, amortization and accretion	5,304	3,615	1,356
	756,519	1,001,580	1,585,572
Loss from operations	(756,519)	(1,001,580)	(1,585,572)
Other income (expenses)	17,547	4,243	3,917
Loss before income taxes	$ (738,972)	$ (997,337)	(1,581,655)
Impairment loss on mineral properties
Inventory write-down