Property, Plant, Equipment and Mine Development (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

estimated useful lives of the building and improvements and machinery and equipment asset categories range from 1 to 30 years. The estimated life of leasehold improvements is the shorter of useful life or remaining life of the lease.

Property, plant, equipment and mine development, net, as of December 31, 2022 and December 31, 2021 consisted of the following:

	December 31,
	2022		2021
	(Dollars in millions)
Land and coal interests	$	2,514.7	$	2,494.1
Buildings and improvements	594.2		550.8
Machinery and equipment	1,543.1		1,386.2
Less: Accumulated depreciation, depletion and amortization	(1,787.0)		(1,480.5)
Property, plant, equipment and mine development, net	$	2,865.0	$	2,950.6