Summary of Significant Accounting Policies - Revenue (Details)	3 Months Ended		9 Months Ended
	Oct. 31, 2022 USD ($) shares	Oct. 31, 2021 USD ($) shares	Oct. 31, 2022 USD ($) contract item MT shares	Oct. 31, 2021 USD ($) shares	Jan. 31, 2022 USD ($)
Disaggregation of Revenue [Line Items]
Number of units outstanding | shares	13,120,010	13,120,010	13,120,010	13,120,010
Revenue from Contract with Customer [Abstract]
Royalty income		$ 15,836,180	$ 9,794,440	$ 52,982,383
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	$ 34,460		$ 34,460		$ 4,631,510
Number of customer contracts | contract			1
Contract asset	$ 0		$ 0		$ 1,431,633
Base Overriding Royalties
Revenue from Contract with Customer [Abstract]
Royalty income		9,644,501	3,829,720	31,929,119
Bonus Royalties
Revenue from Contract with Customer [Abstract]
Royalty income		5,981,907	5,722,317	20,465,070
Fee Royalties
Revenue from Contract with Customer [Abstract]
Royalty income		$ 209,772	$ 242,403	$ 588,194