Property, Plant, Equipment and Mine Development (Tables)

3 Months Ended

Mar. 31, 2024

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant, Equipment and Mine Development

The composition of property, plant, equipment and mine development, net, as of March 31, 2024 and December 31, 2023 is set forth in the table below:

	March 31, 2024		December 31, 2023
	(Dollars in millions)
Land and coal interests	$	2,475.1	$	2,475.2
Buildings and improvements	645.4		647.6
Machinery and equipment	1,842.0		1,787.6
Less: Accumulated depreciation, depletion and amortization	(2,132.3)		(2,066.3)
Property, plant, equipment and mine development, net	$	2,830.2	$	2,844.1