Property, Plant and Equipment

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment:

Property, plant and equipment, at cost, consist of the following at December 31, 2015 and 2014 (in thousands):

	Useful Lives (Years)	December 31,
		2015		2014
Land(a)	—	$	145,912	$	56,249
Land improvements	5 – 30	59,423		49,099
Buildings and improvements(a)	10 – 45	297,163		214,364
Machinery and equipment(b)	2 – 45	2,305,641		2,106,451
Long-term mineral rights and production equipment costs	7 – 60	652,871		85,888
Construction in progress	—	420,152		108,619
Total		$	3,881,162	$	2,620,670

(a) Includes Land under capital lease of $2.8 million and Buildings and improvements under capital lease of $9.9 million at December 31, 2015.

(b) Consists primarily of (1) short-lived production equipment components, office and building equipment and other equipment with estimated lives ranging 2 – 7 years, (2) production process equipment (intermediate components) with estimated lives ranging 8 – 19 years, (3) production process equipment (major unit components) with estimated lives ranging 20 – 29 years, and (4) production process equipment (infrastructure and other) with estimated lives ranging 30 – 45 years.

In 2015, approximately $1.4 billion was allocated to Property, plant and equipment in connection with the acquisition of Rockwood. See Note 2, “Acquisitions” for additional information about the amounts of assets acquired and liabilities assumed upon the acquisition of Rockwood. In 2014, we sold our antioxidant, ibuprofen and propofol businesses and assets to SI Group, Inc. Included in the transaction were our manufacturing sites in Orangeburg, South Carolina and Jinshan, China, along with our antioxidant product lines manufactured in Ningbo, China. In connection with the sale, net property, plant and equipment was reduced by $100.0 million. See Note 3 “Divestitures” for additional information about this transaction.

The cost of property, plant and equipment, including buildings and improvements under capital lease, is depreciated generally by the straight-line method. Depletion of long-term mineral rights is based on the units-of-production method. Depreciation expense amounted to $180.7 million, $97.9 million and $99.3 million during the years ended December 31, 2015, 2014 and 2013, respectively. Depreciation expense related to discontinued operations was $2.3 million and $8.6 million during the years ended December 31, 2014 and 2013, respectively. Interest capitalized on significant capital projects in 2015, 2014 and 2013 was $11.2 million, $2.4 million and $6.1 million, respectively. As of December 31, 2015, accumulated amortization for assets under capital lease acquired from Rockwood was $0.3 million.