PROPERTIES AND EQUIPMENT

The following table presents the components of properties and equipment, net of accumulated depreciation, depletion and amortization:



	September 30, 2013			December 31, 2012
	(in thousands)
Properties and equipment, net:
Crude oil and natural gas properties
Proved	$	1,533,430		$	2,075,924
Unproved	315,233			319,327
Total crude oil and natural gas properties	1,848,663			2,395,251
Pipelines and related facilities	15,749			47,786
Equipment and other	28,780			34,858
Land and buildings	13,612			14,935
Construction in progress	146,921			67,217
Gross properties and equipment	2,053,725			2,560,047
Accumulated depreciation, depletion and amortization	(514,024		)	(943,341		)
Properties and equipment, net	$	1,539,701		$	1,616,706

The above decrease in property and equipment, net, includes decreases in crude oil and natural gas properties, pipelines and related facilities and equipment and other in the amount of $780.0 million and accumulated depreciation, depletion and amortization in the amount of $566.4 million attributable to the divestiture of our Piceance Basin, NECO and certain other non-core Colorado properties in June 2013 and the classification of our shallow upper Devonian (non-Marcellus Shale) Appalachian Basin crude oil and natural gas properties as held for sale in the condensed consolidated balance sheet as of September 30, 2013. See Note 12, Assets Held for Sale, Divestitures and Discontinued Operations, for additional information regarding these properties.

The following table presents impairment charges recorded for crude oil and natural gas properties:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
	(in thousands)
Continuing operations:
Impairment of proved properties	$	3,750	$	—	$	48,750	$	—
Impairment of individually significant unproved properties	154		154		979		462
Amortization of individually insignificant unproved properties	568		234		2,704		870
Total continuing operations	4,472		388		52,433		1,332
Discontinued operations:
Amortization of individually insignificant unproved properties	—		7		3		86
Total discontinued operations	—		7		3		86
Total impairment of crude oil and natural gas properties	$	4,472	$	395	$	52,436	$	1,418

In the first quarter of 2013, we recognized an impairment charge of approximately $45.0 million related to all of our shallow upper Devonian (non-Marcellus Shale) Appalachian Basin producing properties located in West Virginia and Pennsylvania owned directly by us, as well as through our proportionate share of PDCM and our affiliated partnerships. The impairment charge represented the excess of the carrying value of the assets over the estimated fair value, less cost to sell. The fair value of the assets was determined based upon estimated future cash flows from unrelated third-party bids, a Level 3 input. Pursuant to a purchase and sale agreement dated October 8, 2013 with an unrelated third-party, we determined that the carrying value of the above-mentioned properties exceeded the transaction sales price, a Level 3 input, less costs to sell. As a result, we recognized an additional impairment charge of approximately $3.8 million in the third quarter of 2013 to reduce the carrying value of the net assets to reflect the current net sales price. The impairment charge was included in the statement of operations line item impairment of crude oil and natural gas properties. See Note 12, Assets Held for Sale, Divestitures and Discontinued Operations, and Note 15, Subsequent Events, for additional information regarding the potential sale of these properties. We expect this sale to close in the fourth quarter of 2013. However, there can be no assurance we will be successful in closing this divestiture.