Note 14 - Segmented Information - Operating Results by Geographic Segments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Mineral Property Expenditures	$ 1,453,358	$ 981,493	$ 3,218,818	$ 3,638,408
General and administrative	1,952,616	2,407,571	6,395,014	7,526,698
Depreciation, amortization and accretion	86,387	88,294	259,970	268,066
	3,492,361	3,477,358	9,873,802	11,433,172
Loss from operations	(3,492,361)	(3,477,358)	(9,873,802)	(11,433,172)
Other income (expenses)	(1,526,501)	(681,240)	(958,126)	(1,891,364)
Loss before income taxes	(5,018,862)	(4,158,598)	(10,831,928)	(13,324,536)
United States Texas [Member]
Mineral Property Expenditures	1,042,836	611,170	2,197,324	1,795,078
General and administrative	1,391,225	1,427,445	4,461,280	4,587,983
Depreciation, amortization and accretion	78,628	79,903	235,040	247,687
	2,512,689	2,118,518	6,893,644	6,630,748
Loss from operations	(2,512,689)	(2,118,518)	(6,893,644)	(6,630,748)
Other income (expenses)	(659,194)	(677,570)	(1,945,311)	(1,888,966)
Loss before income taxes	(3,171,883)	(2,796,088)	(8,838,955)	(8,519,714)
United States Arizona [Member]
Mineral Property Expenditures	22,769	23,136	75,756	69,698
General and administrative	3,779	3,389	10,650	10,488
Depreciation, amortization and accretion
	26,548	26,525	86,406	80,186
Loss from operations	(26,548)	(26,525)	(86,406)	(80,186)
Other income (expenses)	(4,611)	(4,611)	(14,146)	(14,146)
Loss before income taxes	(31,159)	(31,136)	(100,552)	(94,332)
United States Wyoming [Member]
Mineral Property Expenditures	179,687	165,566	474,981	1,134,782
General and administrative	25,746	34,533	80,248	558,326
Depreciation, amortization and accretion	3,717	3,716	11,156	9,125
	209,150	203,815	566,385	1,702,233
Loss from operations	(209,150)	(203,815)	(566,385)	(1,702,233)
Other income (expenses)	681	(249)	1,081	1,241
Loss before income taxes	(208,469)	(204,064)	(565,304)	(1,700,992)
United States Other States [Member]
Mineral Property Expenditures	15,345	15,846	54,565	52,205
General and administrative	1,142	1,141	3,090	3,385
Depreciation, amortization and accretion	249	249	747	747
	16,736	17,236	58,402	56,337
Loss from operations	(16,736)	(17,236)	(58,402)	(56,337)
Other income (expenses)			1,578,864
Loss before income taxes	(16,736)	(17,236)	1,520,462	(56,337)
CANADA
Mineral Property Expenditures	375		16,098
General and administrative	507,728	794,682	1,732,769	2,153,051
Depreciation, amortization and accretion	2,590	3,600	9,077	7,717
	510,693	798,282	1,757,944	2,160,768
Loss from operations	(510,693)	(798,282)	(1,757,944)	(2,160,768)
Other income (expenses)	(872,851)		(590,819)
Loss before income taxes	(1,383,544)	(798,282)	(2,348,763)	(2,160,768)
PARAGUAY
Mineral Property Expenditures	192,346	165,775	400,094	586,645
General and administrative	22,996	146,381	106,977	213,465
Depreciation, amortization and accretion	1,203	826	3,950	2,790
	216,545	312,982	511,021	802,900
Loss from operations	(216,545)	(312,982)	(511,021)	(802,900)
Other income (expenses)	9,474	1,190	12,205	10,507
Loss before income taxes	$ (207,071)	$ (311,792)	$ (498,816)	$ (792,393)