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CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS (Tables)
12 Months Ended
Dec. 31, 2020
CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS  
Schedule of total revenues from major customers

Year Ended December 31, 

 

    

Segment

    

2020

2019

2018

 

(in thousands)

Customer A

 

Illinois Basin

$

197,379

$

228,500

$

219,115

Customer B

Appalachia

213,319

Customer C

Illinois Basin

157,271

Customer D

 

Illinois Basin/Appalachia

 

137,785