XML 44 R26.htm IDEA: XBRL DOCUMENT v3.8.0.1
Note 6 - Asset Retirement Obligations (ARO) (Tables)
 12 Months Ended
Dec. 31, 2017
Notes Tables  
Schedule of Change in Asset Retirement Obligation [Table Text Block]
   
Year Ended December 31,
  
   
2017
    
2016
  
                 
Balance at beginning of year
   $
10,128,634
     $
2,095,073
  
Additional asset retirement obligations incurred
    
2,033,722
      
489,489
  
Asset retirement obligations assumed in Knox Creek acquisition
    
—
      
7,416,164
  
Accretion expense
    
405,106
      
229,304
  
Revisions to estimates
    
(220,670
 )    
(101,396
 )
Balance at end of year
   $
12,346,792
     $
10,128,634