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Asset Retirement Obligations
12 Months Ended
Sep. 30, 2021
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations ASSET RETIREMENT OBLIGATIONS
The following table provides a roll-forward of the AROs reflected in the Company’s Consolidated Balance Sheets:
20212020
Beginning Balance$11,759 $12,675 
Purchase accounting in connection with the KMG Acquisition— (860)
Liabilities Settled(21)— 
Accretion of discount585 599 
Estimate revision(290)(655)
Ending Balance at September 30$12,033 $11,759