Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

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,
	2016			2015
	(millions of dollars)
Mineral rights and reserves	$	547.8		$	553.8
Land		42.7			39.8
Buildings		195.6			179.7
Machinery and equipment		1,193.6			1,130.7
Furniture and fixtures and other		123.3			209.7
Construction in progress		38.4			53.6
		2,141.4			2,167.3
Less: accumulated depreciation and depletion		(1,089.6	)		(1,063.0	)
Property, plant and equipment, net	$	1,051.8		$	1,104.3