PROPERTY, PLANT AND EQUIPMENT

9 Months Ended

Sep. 30, 2016

Property, Plant and Equipment [Abstract]

Property, plant and equipment consisted of the following (in thousands):



	September 30, 2016		December 31, 2015
Land	$	122,337	$	100,582
Asset retirement costs (non-landfill)	14,590		12,434
Landfill assets	142,587		136,624
Buildings and improvements	379,435		344,209
Camp equipment	156,838		149,361
Vehicles	535,804		500,619
Equipment	1,465,378		1,328,915
Furniture and fixtures	5,546		5,337
Construction in progress	147,569		113,657
	2,970,084		2,691,738
Less - accumulated depreciation and amortization	1,321,513		1,159,271
Total property, plant and equipment, net	$	1,648,571	$	1,532,467

Interest in the amount of $1.5 million and $4.0 million was capitalized to fixed assets during the three and nine months ended September 30, 2016, respectively. Interest in the amount of $0.6 million and $1.2 million was capitalized to fixed assets during the three and nine months ended September 30, 2015, respectively. Depreciation expense, inclusive of landfill amortization, was $62.6 million and $185.4 million for the three and nine months ended September 30, 2016, respectively. Depreciation expense, inclusive of landfill amortization, was $59.2 million and $175.5 million for the three and nine months ended September 30, 2015, respectively.