SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue (Details)	3 Months Ended		9 Months Ended
	Oct. 31, 2020 USD ($)	Oct. 31, 2019 USD ($)	Oct. 31, 2020 USD ($) item contract MT	Oct. 31, 2019 USD ($)	Jan. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Royalty Revenue	$ 5,736,151	$ 6,488,299	$ 15,090,006	$ 26,151,926
Base overriding royalties, first tier portion percentage			90.00%
Base overriding royalties, first tier shipment ceiling (in million tons) | MT			4
Base overriding royalties, second tier portion percentage			85.00%
Base overriding royalties, second tier shipment ceiling (in million tons) | MT			2
Base overriding royalties, third tier portion percentage			25.00%
Base overriding royalties, third tier shipment threshold (in million tons) | MT			6
Base overriding royalties, number of volume thresholds for transaction price | item			4
Base overriding royalties, volume threshold for transaction price | MT			1
Accrued income receivable	1,183,330		$ 1,183,330		$ 69,588
Number of customer contracts | contract			1
Net contract asset	736,137		$ 736,137
Net contract liability					2,511,720
Contract asset	1,107,516		1,107,516		192,059
Contract liability	371,379		371,379		$ 2,703,779
Base Overriding Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	3,142,465	3,674,830	8,499,261	15,069,353
Bonus Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	2,448,652	2,640,101	6,271,940	10,565,280
Fee Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	$ 145,034	$ 173,368	$ 318,805	$ 517,293