Mineral Interests and Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2013

Mineral Interests and Property, Plant and Equipment

Schedule of property, plant and equipment

Property, plant and equipment are summarized as follows (in thousands):

	December 31,
	2013			2012
Land	$	79,733		$	87,088
Land improvements		43,107			19,949
Buildings and leasehold improvements		420,142			362,296
Mine development costs		255,680			270,768
Machinery and equipment		1,569,318			1,402,417
Gas properties and related development		188,527			223,200
Construction in progress		61,933			163,096
Total		2,618,440			2,528,814
Less: Accumulated depreciation		(980,888	)		(796,683	)
Net	$	1,637,552		$	1,732,131