Exhibit 12.1

Ratio of Earnings to Fixed Charges

The following table sets forth our ratios of consolidated earnings to fixed charges for the periods presented:

	Year Ended December 31,															Nine Months Ended September 30, 2012
	2007			2008			2009			2010			2011
	(in thousands, except ratios)
	(unaudited)
Income before income taxes	$	215,759		$	(828,482	)	$	(262,030	)	$	129,793		$	264,334		$	89,274
Add: Fixed charges		62,438			54,213			46,974			43,304			52,581			43,529
Add: Amortization of capitalized interest		1,265			1,273			2,667			1,353			1,037			703
Less: Capitalized interest		(25,100	)		(19,292	)		(6,662	)		(5,395	)		(9,877	)		(9,899	)
Earnings before fixed charges	$	254,362		$	(792,288	)	$	(219,051	)	$	169,055		$	308,075		$	123,607
Fixed charges:
Interest expense, net of capitalized interest	$	37,088		$	34,709		$	40,087		$	37,706		$	42,516		$	33,510
Capitalized interest		25,100			19,292			6,662			5,395			9,877			9,899
Portion of rental expense representative of an interest factor		250			212			225			203			188			120
Total fixed charges	$	62,438		$	54,213		$	46,974		$	43,304		$	52,581		$	43,529
Ratio of earnings to fixed charges		4.1			—	(1)		—	(2)		3.9			5.9			2.8

(1) Earnings were inadequate to cover fixed charges for the year ended December 31, 2008 by $846.5 million. Earnings for the year ended December 31, 2008 included an impairment write down of $1,182.8 million.

(2) Earnings were inadequate to cover fixed charges for the year ended December 31, 2009 by $266.0 million. Earnings for the year ended December 31, 2009 included an impairment write down of $218.9 million.