Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

Depreciation of plant and equipment is calculated on the straight-line method over their estimated useful lives or lease terms generally as follows:

	Years
Buildings and improvements	10 to 45
Machinery and equipment	3 to 25
Leasehold improvements	Life of Lease

Property, plant and equipment consists of the following at December 31:

	December 31,
	2017		2016
Plant and Equipment	$	2,757,062	$	2,680,453
Coal Properties and Surface Lands	857,031		861,048
Airshafts	392,266		381,755
Mine Development	344,139		344,139
Advance Mining Royalties	325,855		326,000
Total Property, Plant and Equipment	4,676,353		4,593,395
Less Accumulated Depreciation, Depletion and Amortization	2,554,056		2,413,125
Total Property, Plant and Equipment, Net	$	2,122,297	$	2,180,270