Intangible Assets

12 Months Ended

Dec. 31, 2011

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets Disclosure

Intangible Assets

Intangible assets other than goodwill, which are subject to amortization, consist of the following:

	Gross Carrying Amount		Accumulated Amortization			Net Balance
Balance at December 31, 2011
Coal supply agreement	$	84.2	$	(26.3	)	$	57.9
Balance at December 31, 2010
Coal supply agreement	$	84.2	$	(24.2	)	$	60.0

During 2010, NACoal finalized an agreement with Mississippi Power Company to provide lignite coal from its Liberty Mine to the Ratcliffe power plant currently being built in Mississippi. Upon the execution of this agreement, the Company determined that its intangible asset at the Mississippi Lignite Mining Company was impaired. Accordingly, the Company recorded an impairment charge of $0.7 million for other intangible assets at NACoal during 2010.

Amortization expense for intangible assets was $2.1 million, $3.5 million and $2.9 million in 2011, 2010 and 2009, respectively. Amortization expense for 2010 includes an impairment charge of $0.7 million for other intangible assets at NACoal.

Expected annual amortization expense of other intangible assets for the next five years is as follows: $2.7 million in 2012, $2.4 million in 2013 and $2.7 million in 2014, 2015 and 2016, respectively. The amortization period for the coal supply agreement is 30 years.