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Note 9 - Inventories (Tables)
12 Months Ended
Dec. 31, 2020
Notes Tables  
Schedule of Inventory, Current [Table Text Block]
  

December 31,

 
  

2020

  

2019

 

Coal

 $7,163  $2,484 

Supplies

  49,037   51,647 

Total Inventories

 $56,200  $54,131