Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Major Categories of Property, Plant and Equipment and Accumulated Depreciation and Depletion

The major categories of property, plant and equipment and accumulated depreciation and depletion are presented below:

	December 31,
(millions of dollars)	2019			2018
Mineral rights and reserves	$	571.0		$	582.8
Land		47.5			47.3
Buildings		218.1			219.3
Machinery and equipment		1,241.2			1,235.6
Furniture and fixtures and other		144.1			134.8
Construction in progress		35.1			36.1
		2,257.0			2,256.0
Less: accumulated depreciation and depletion		(1,204.2	)		(1,153.1	)
Property, plant and equipment, net	$	1,052.8		$	1,102.9