Property, Plant, Equipment and Mine Development (Tables)

9 Months Ended

Sep. 30, 2023

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 September 30, 2023 and December 31, 2022 is set forth in the table below:

	September 30, 2023		December 31, 2022
	(Dollars in millions)
Land and coal interests	$	2,511.9	$	2,514.7
Buildings and improvements	633.5		594.2
Machinery and equipment	1,671.0		1,543.1
Less: Accumulated depreciation, depletion and amortization	(2,010.9)		(1,787.0)
Property, plant, equipment and mine development, net	$	2,805.5	$	2,865.0