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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Base overriding royalties (Details)	6 Months Ended
	Jul. 31, 2025 MT
Disaggregation of Revenue
Base overriding royalties, first tier portion percentage	90.00%
Base overriding royalties, first tier shipment ceiling (in million tons)	4
Base overriding royalties, second tier portion percentage	85.00%
Base overriding royalties, second tier shipment ceiling (in million tons)	2
Base overriding royalties, third tier portion percentage	25.00%
Base overriding royalties, third tier shipment threshold (in million tons)	6
First million tons shipped or deemed Shipped
Disaggregation of Revenue
Royalty earned on tons shipped or deemed shipped, percentage	2.50%
Second million tons shipped or deemed Shipped
Disaggregation of Revenue
Royalty earned on tons shipped or deemed shipped, percentage	3.50%
Third million tons shipped or deemed Shipped
Disaggregation of Revenue
Royalty earned on tons shipped or deemed shipped, percentage	5.00%
Fourth million tons shipped or deemed Shipped
Disaggregation of Revenue
Royalty earned on tons shipped or deemed shipped, percentage	5.50%
Beyond four million tons shipped or deemed Shipped
Disaggregation of Revenue
Royalty earned on tons shipped or deemed shipped, percentage	6.00%

X

- Definition

The ceiling quantity for the first tier of base overriding royalties earned. Shipments up to this amount are subject to the first tier portion percentage in calculating the royalties earned.

+ References

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- Definition

The ceiling quantity for the second tier of base overriding royalties earned. Shipments up to this amount, above the first tier ceiling, are subject to the second tier portion percentage in calculating the royalties earned.

+ References

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The percentage applied to the quantity shipped in the first tier, to determine the quantity on which royalties are earned.

+ References

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The percentage applied to the quantity shipped in the second tier, to determine the quantity on which royalties are earned.

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The percentage applied to the quantity shipped in the third tier, to determine the quantity on which royalties are earned.

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- Definition

The threshold quantity for the third tier of base overriding royalties earned. Shipments above this amount are subject to the third tier portion percentage in calculating the royalties earned.

+ References

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- Definition

Percentage of royalty earned on the tons shipped or deemed Shipped.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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