LEASES: (Tables)

12 Months Ended

Dec. 31, 2024

LEASES:

Schedule of the operating lease expense recognized

The operating lease expense recognized in the years ended December 31, 2024, 2023 and 2022 was classified as follows (in millions):

Classification	2024		2023		2022
Cost of sales (exclusive of depreciation, amortization and depletion)	$	106.0	$	115.4	$	115.5
Selling, general and administrative		0.1		0.1		0.1
Exploration		0.1		0.1		0.1
Total lease expense	$	106.2	$	115.6	$	115.7

Schedule of Maturities of lease liabilities

	Lease liabilities
Year	(in millions)
2025	$	114.6
2026		114.6
2027		114.3
2028		114.0
2029		112.8
After 2029		317.1
Total lease payments	$	887.4
Less: interest on lease liabilities		(147.9)
Present value of lease payments	$	739.5