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LEASES: | 9 Months Ended
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Sep. 30, 2025
LEASES: |
LEASES: | ​ NOTE 7 — LEASES: ​ The Company has operating leases for power generating facilities, vehicles and properties. The Company recognizes leasing expenses for these leases on a straight-line basis over the lease term. Some of the Company’s leases include both lease and non-lease components which are accounted for separately. The Company’s leases have remaining lease terms of less than one year to seven years, and do not include options to extend the leases. The Company’s lease agreements do not contain options to purchase the leased assets or to terminate the leases before the expiration date. In addition, the Company’s lease contracts have no material residual value guarantees or material restrictive covenants. As none of the Company’s leases stipulate an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. ​ The weighted average of the remaining lease term for the Company’s leases is approximately six years, and the weighted average discount rate for these leases is 5.01%. ​ The operating lease expense recognized in the nine-month periods ended September 30, 2025 and 2024 was classified as follows (in millions): ​
​ | ​ | ​ | ​ | ​ | ​ | ​
Classification |  | 2025 |  | 2024
Cost of sales (exclusive of depreciation, amortization and depletion) |  | $ | 83.5 | ​ | $ | 77.4
Selling, general and administrative | ​ |  | 0.1 | ​ |  | 0.1
Exploration | ​ |  | 0.1 | ​ |  | 0.1
Total lease expense |  | $ | 83.7 | ​ | $ | 77.5
​ ​ Maturities of lease liabilities are as follows: ​
​ | ​ | ​ | ​
​ | ​ | Lease liabilities
Year |  | (in millions)
2025 |  | $ | 29.1
2026 | ​ |  | 116.2
2027 | ​ |  | 115.7
2028 | ​ |  | 115.2
2029 | ​ |  | 113.2
After 2029 | ​ |  | 317.3
Total lease payments |  | $ | 806.7
Less: interest on lease liabilities | ​ |  | (123.3)
Present value of lease payments |  | $ | 683.4
​

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- Definition The entire disclosure for operating leases of lessee. Includes, but is not limited to, description of operating lease and maturity analysis of operating lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/842-20/tableOfContent + Details
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