		December 31,		December 31,
		2012		2011
Proven Properties:
Acquisition, equipment, exploration, drilling and environmental costs	$	7,235,765	$	5,974,604
Less: Accumulated depletion, depreciation and amortization(1)		(5,578,265)		(2,322,982)
		1,657,500		3,651,622
Unproven Properties:
Acquisition and exploration costs not being amortized (2)		-		537,526
Net capitalized costs - oil and gas properties	$	1,657,500	$	4,189,148

On a unit basis, DD&A from continuing operations was $1.51, $1.41 and $1.13 per Mcfe for the years ended December 31, 2012, 2011 and 2010, respectively.

(1) During 2012, the Company recorded a $2.9 billion non-cash write-down of the carrying value of the Company's proved oil and gas properties as a result of ceiling test limitations, which is reflected within ceiling test and other impairments in the accompanying Consolidated Statements of Operations. The ceiling test was calculated based upon the average of quoted market prices in effect on the first day of the month for the preceding twelve month period at December 31, 2012, September 30, 2012 and June 30, 2012 of $2.76 per MMBtu, $2.83 per MMBtu and $3.15 per MMBtu for Henry Hub natural gas, respectively, and $94.71 per barrel, $94.97 per barrel and $95.67 per barrel for West Texas Intermediate oil, respectively, adjusted for market differentials. The Company did not have any write-downs related to the full cost ceiling limitation in 2011.

(2) Interest is capitalized on the cost of unevaluated oil and natural gas properties that are excluded from amortization and actively being evaluated as well as on work in process relating to gathering systems that are not currently in service. For the years ended December 31, 2012 and 2011, total interest on outstanding debt was $103.2 million and $93.9 million, respectively, of which $15.0 million and $30.7 million, respectively, was capitalized on the cost of unevaluated oil and natural gas properties and work in process relating to gathering systems that are not currently in service.

At December 31, 2012, all costs related to unevaluated properties that were previously excluded from capitalized costs being amortized have been impaired and transferred to the capitalized costs being amortized in the full cost pool.

		Total		2012		2011		2010		Prior
Acquisition costs	$	-	$	(481,689)	$	24,583	$	411,326	$	45,780
Exploration costs		-		(9,962)		198		-		9,764
Capitalized interest		-		(45,875)		26,498		19,377		-
Unproven properties	$	-	$	(537,526)	$	51,279	$	430,703	$	55,544