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Inventories (Tables)
3 Months Ended
Mar. 31, 2012
Inventories  
Schedule of inventories
 
  March 31,
2012
  December 31,
2011
 

Coal

  $ 239,244   $ 180,537  

Raw materials and supplies

    70,498     59,900  
           

Total inventories

  $ 309,742   $ 240,437