PROPERTY, PLANT AND EQUIPMENT (Tables)

3 Months Ended

Mar. 31, 2019

Property, Plant and Equipment [Abstract]

Value Of Each Of The Major Classes Of Consolidated Depreciable Assets

The following table indicates the carrying value of each of the major classes of our depreciable assets:

	(In Millions)
	March 31, 2019			December 31, 2018
Land rights and mineral rights	$	549.6		$	549.6
Office and information technology	70.5			70.0
Buildings	87.4			87.2
Mining equipment	568.4			548.5
Processing equipment	660.9			645.8
Electric power facilities	58.7			58.7
Land improvements	23.8			23.8
Asset retirement obligation	14.8			14.8
Other	25.5			25.2
Construction-in-progress	392.0			284.8
	2,451.6			2,308.4
Allowance for depreciation and depletion	(1,041.3		)	(1,022.4		)
	$	1,410.3		$	1,286.0