PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT

NOTE 5 - PROPERTY, PLANT AND EQUIPMENT

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

	(In Millions)
	December 31,
	2018			2017
Land rights and mineral rights	$	549.6		$	549.6
Office and information technology	70.0			65.8
Buildings	87.2			85.2
Mining equipment	548.5			533.9
Processing equipment	645.8			610.9
Electric power facilities	58.7			56.9
Land improvements	23.8			23.7
Asset retirement obligation	14.8			16.9
Other	25.2			25.2
Construction-in-progress	284.8			32.6
	2,308.4			2,000.7
Allowance for depreciation and depletion	(1,022.4		)	(966.9		)
	$	1,286.0		$	1,033.8

We recorded depreciation expense of $65.6 million, $65.8 million and $84.0 million in the Statements of Consolidated Operations for the years endedDecember 31, 2018, 2017 and 2016, respectively.

We recorded capitalized interest of $6.5 million into construction-in-progress during the year ended December 31, 2018.

The net book value of the land rights and mineral rights is as follows:

	(In Millions)
	December 31,
	2018			2017
Land rights	$	12.4		$	12.4
Mineral rights:
Cost	$	537.2		$	537.2
Depletion	(126.5		)	(119.1		)
Net mineral rights	$	410.7		$	418.1

We recorded depletion expense of $7.4 million, $6.8 million and $3.8 million in the Statements of Consolidated Operations for the years endedDecember 31, 2018, 2017 and 2016, respectively.