Note 14 - Segmented Information - Long-term Assets by Geographic Segments (Details) - USD ($)	Apr. 30, 2019	Jul. 31, 2018	Apr. 30, 2018	Jul. 31, 2017
Mineral Rights and Properties	$ 63,753,971	$ 71,122,576
Property, Plant and Equipment	7,121,828	7,101,552
Restricted cash	1,812,843	1,789,899	$ 1,779,182	$ 1,706,028
Equity-Accounted Investment	9,058,803	693,502
Other Long-Term Assets	338,770	563,052
Total Long-Term Assets	82,086,215	81,270,581
United States Texas [Member]
Mineral Rights and Properties	12,700,030	12,729,697
Property, Plant and Equipment	6,405,816	6,362,608
Restricted cash	1,723,870	1,700,926
Equity-Accounted Investment
Other Long-Term Assets	242,042	416,519
Total Long-Term Assets	21,071,758	21,209,750
United States Arizona [Member]
Mineral Rights and Properties	4,377,477	11,069,018
Property, Plant and Equipment
Restricted cash	15,000	15,000
Equity-Accounted Investment
Other Long-Term Assets
Total Long-Term Assets	4,392,477	11,084,018
United States Wyoming [Member]
Mineral Rights and Properties	31,527,870	31,527,870
Property, Plant and Equipment	346,235	357,392
Restricted cash	73,973	73,973
Equity-Accounted Investment
Other Long-Term Assets	96,728	146,533
Total Long-Term Assets	32,044,806	32,105,768
United States Other States [Member]
Mineral Rights and Properties	88,071	735,468
Property, Plant and Equipment
Restricted cash
Equity-Accounted Investment
Other Long-Term Assets
Total Long-Term Assets	88,071	735,468
CANADA
Mineral Rights and Properties	546,938	546,938
Property, Plant and Equipment	16,813	25,889
Restricted cash
Equity-Accounted Investment	9,058,803	693,502
Other Long-Term Assets
Total Long-Term Assets	9,622,554	1,266,329
PARAGUAY
Mineral Rights and Properties	14,513,585	14,513,585
Property, Plant and Equipment	352,964	355,663
Restricted cash
Equity-Accounted Investment
Other Long-Term Assets
Total Long-Term Assets	$ 14,866,549	$ 14,869,248