Asset Retirement Obligations

3 Months Ended

Mar. 31, 2020

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

14. Asset Retirement Obligations

Asset retirement obligations are recorded in Other non-current liabilities in the Consolidated Balance Sheets.  Changes in the asset retirement obligations during the three months ended March 31, 2020 and 2019 were as follows:

	March 31, 2020		March 31, 2019
	(in thousands)
Beginning balance	$	46,510	$	31,199
Accretion		517		517
Additions and revisions of prior estimates		6,474		-
Ending balance	$	53,501	$	31,716

Asset retirement obligations increased from March 31, 2019 to March 31, 2020 primarily due to shortened mines lives and renewed estimates recorded in the fourth quarter of 2019.