Revenue Recognition

9 Months Ended

Sep. 30, 2025

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue Recognition

Nature of Performance Obligations: At contract inception, we assess the goods and services promised in our contracts with customers and identify a performance obligation for each promised good or service that is distinct. To identify the performance obligations, we consider all of the goods or services promised in the contract regardless of whether they are explicitly stated or are implied by customary business practices.

Each mine or mine area has a contract with our respective customer that represents a contract under ASC 606. For our consolidated entities, our performance obligations vary by contract and consist of the following:

At MLMC, each MMBtu delivered during the production period is considered a separate performance obligation. Revenue is recognized at the point in time that control of each MMBtu of lignite transfers to the customer. Fluctuations in revenue from period to period generally result from changes in customer demand.

In the Contract Mining segment, the management service to oversee the operation of the equipment, and delivery of aggregates or other minerals is the performance obligation accounted for as a series. Performance momentarily creates an asset that the customer simultaneously receives and consumes; therefore, control is transferred to the customer over time. Consistent with the conclusion that the customer simultaneously receives and consumes the benefits provided, an input-based measure of progress is appropriate. As each month of service is completed, revenue is recognized for the amount of actual costs incurred, plus the management fee or fixed fee and the general and administrative fee (as applicable). Fluctuations in revenue from period to period result from changes in customer demand primarily due to increases and decreases in activity levels on individual contracts and variances in reimbursable costs. Revenue from part sales is recognized upon transfer of control of the parts to the customer.

The Minerals and Royalties segment enters into contracts which grant the right to explore, develop, produce and sell minerals controlled by us. These arrangements result in the transfer of mineral rights for a period of time; however, no rights to the actual land are granted other than access for purposes of exploration, development, production and sales. The mineral rights revert back to us at the expiration of the contract.

Under these contracts, granting exclusive right, title, and interest in and to minerals, if any, is the performance obligation. The performance obligation under these contracts represents a series of distinct goods or services whereby each day of access that is provided is distinct. The transaction price consists of a variable sales-based royalty and, in certain arrangements, a fixed component in the form of an up-front lease bonus payment. As the amount of consideration we will ultimately be entitled to is entirely susceptible to factors outside of our control, the entire amount of variable consideration is constrained at contract inception. We believe that the pricing provisions of royalty contracts are customary in the industry. Up-front lease bonus payments represent the fixed portion of the transaction price and are recognized over the primary term of the contract, which is generally three to five years.

Mitigation Resources generates and sells stream and wetland mitigation credits (known as mitigation banking) and provides comprehensive reclamation and restoration construction services. In mitigation banking, each mitigation credit sale is considered a separate performance obligation. Mitigation banks are regulated and approved by the U.S. Army Corps of Engineers and other federal, state and local agencies. Mitigation credits are released in phases over the life of the mitigation bank. Revenue is recognized at the point in time that control of each mitigation credit transfers to the customer. Fluctuations in revenue from period to period generally result from changes in timing of mitigation credit releases and/or customer demand.

For other restoration construction services, contracts are generally structured as an agreement under which Mitigation Resources is reimbursed for all costs incurred in performing the required services plus a fixed fee. The services provided represent the performance obligation and are accounted for as a series. Performance momentarily creates an asset that the customer simultaneously receives and consumes; therefore, control is transferred to the customer as work is completed. Consistent with the conclusion that the customer simultaneously receives and consumes the benefits provided, an input-based measure of progress is appropriate. As each month of service is completed, revenue is recognized for the amount of actual costs incurred, plus the fixed fee. Fluctuations in revenue from period to period result from increases and decreases in activity levels of individual contracts and variances in reimbursable costs.

Significant Judgments: The contracts with our customers in the Utility Coal Mining and Contract Mining segments contain different types of variable consideration including, but not limited to, management fees that adjust based on volumes or MMBtu delivered. However, the terms of these variable payments relate specifically to our efforts to satisfy one or more, but not all, of the performance obligations (or to a specific outcome from satisfying the performance obligations) in the contract. Therefore, we allocate each variable payment (and subsequent changes to that payment) entirely to the specific performance obligation to which it relates. Management fees, as well as general and administrative fees, are also adjusted based on changes in specified indices (e.g., CPI) to compensate for general inflation changes. Index adjustments, if applicable, are effective prospectively.

In the Minerals and Royalties segment, we have the right to receive revenues from the sale of oil and natural gas through sales of the third-party lessees in which we own a mineral or royalty interest. Revenue is recognized at the point control of the product is transferred from the operator to the purchaser. Those purchasers remit payment to the operator and the operator, in turn, remits payment to us. Receivables from third-party lessees for which we did not receive actual production information, either due to timing delays or due to the unavailability of data at the time when revenues are recognized, are estimated using expected sales volumes and estimated prices. The difference between our estimates and the actual amounts received is recorded in the month that payment is received from the third-party lessee. We typically receive payment for oil and natural gas sales within 90 days of the month of delivery. For the three and nine months ended September 30, 2025 and September 30, 2024, respectively, differences between our pricing estimates and the actual amounts received from operators were immaterial.

Cost Reimbursement: Certain contracts include reimbursement from customers of actual costs incurred for the purchase of supplies, equipment and services in accordance with contractual terms. Such reimbursable revenue is variable and subject to uncertainty, as the amounts received and timing thereof is highly dependent on factors outside of our control. Accordingly, reimbursable revenue is fully constrained and not recognized until the uncertainty is resolved, which typically occurs when the related costs are incurred on behalf of a customer. We are considered a principal in such transactions and record the associated revenue at the gross amount billed to the customer with the related costs recorded as an expense within cost of sales.

At the Thacker Pass lithium project, in addition to management fee income, the customer will reimburse Sawtooth for certain capital expenditures. Sawtooth will recognize revenue over the estimated useful life of the asset on a straight-line basis as the performance obligation is satisfied over time. In prior years, the customer received a $3.5 million advance from Sawtooth, which is included in the long-term contract asset. The customer will pay a $4.7 million success fee to Sawtooth if commercial mining milestones are met, at which time Sawtooth will recognize the revenue for the difference between the success fee and the amount advanced. If commercial mining milestones are not met, the customer will only repay the $3.5 million advance.

Prior Period Performance Obligations: As discussed above, we record royalty income in the month production is delivered to the purchaser. The expected sales volumes and prices for these properties are estimated and recorded in Other current assets in the accompanying Unaudited Condensed Consolidated Balance Sheets. The difference between our estimates and the actual amounts received is recorded in the month that payment is received from the third-party lessee. For the three and nine months ended September 30, 2025, royalty income recognized in the reporting period relating to production satisfied in prior periods was immaterial and $1.5 million, respectively. For the three and nine months ended September 30, 2024, royalty income recognized in the reporting period relating to production satisfied in prior periods was immaterial.

Disaggregation of Revenue: In accordance with ASC 606-10-50, we disaggregate revenue from contracts with customers into major goods and service lines and timing of transfer of goods and services. We determined that disaggregating revenue into these categories achieves the disclosure objective of depicting how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Our business consists of the Utility Coal Mining, Contract Mining and Minerals and Royalties segments as well as Unallocated Items. See Note 7 to the Unaudited Condensed Consolidated Financial Statements for further discussion of segment reporting. The following table disaggregates revenue by major sources as of September 30:

	THREE MONTHS ENDED				NINE MONTHS ENDED
	SEPTEMBER 30				SEPTEMBER 30
	2025		2024		2025		2024
Timing of Revenue Recognition
Transferred at a point in time	$	20,125	$	17,134	$	70,451	$	46,740
Transferred over time	56,489		44,522		139,969		120,550
Total revenues	$	76,614	$	61,656	$	210,420	$	167,290

Contract Balances: The opening and closing balances of our current and long-term contract assets and liabilities and receivables are as follows:

	Contract balances
	Trade accounts receivable		Contract asset (current)		Contract asset (long-term)		Contract liability (current)		Contract liability (long-term)
Balance at January 1, 2025	$	49,706	$	313	$	3,500	$	484	$	5,119
Balance at September 30, 2025	30,889		332		3,500		1,003		9,514
Increase (decrease)	$	(18,817)	$	19	$	—	$	519	$	4,395

We expect to recognize $0.7 million in the remainder of 2025, $0.4 million in 2026 and 2027, $1.2 million in 2028, $2.6 million in 2029 and $5.3 million thereafter related to the contract liability remaining at September 30, 2025. The difference between the opening and closing balances of our contract balances results from the timing difference between our performance and the customer’s payment.

We have no contract assets recognized from the costs to obtain or fulfill a contract with a customer.