SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue (Details)	3 Months Ended
	Apr. 30, 2020 USD ($) contract item MT	Apr. 30, 2019 USD ($)	Jan. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Royalty Revenue	$ 2,135,494	$ 5,361,790
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	$ 30,983		$ 69,588
Number of customer contracts | contract	1
Net contract liability	$ 791,162		2,511,720
Contract asset	1,003,962		192,059
Contract liability	1,795,124		$ 2,703,779
Base Overriding Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	1,182,012	3,068,019
Bonus Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	779,712	2,106,957
Fee Royalties
Revenue from Contract with Customer [Abstract]
Royalty Revenue	$ 173,770	$ 186,814