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Asset Retirement Obligations (Tables)
12 Months Ended
Dec. 31, 2011
Asset Retirement Obligations  
Change in asset retirement obligations

 

 

 

 

2011

 

2010

 

Asset retirement obligations at the beginning of year

 

$

329

 

$

302

 

Changes attributable to:

 

 

 

 

 

Accretion expense

 

19

 

22

 

Estimated cash flow revisions

 

(68

)

5

 

Asset retirement obligations at the end of year

 

$

280

 

$

329