ASSET RETIREMENT OBLIGATIONS AND RESTRICTED CASH

The following table summarizes the Company’s asset retirement obligations:



	March 31, 2020		December 31, 2019
Asset retirement obligation, beginning of period	$	18,972	$	19,104
Revision of estimate	—		(2,063		)
Accretion of liabilities	478		1,931
Asset retirement obligation, end of period	$	19,450	$	18,972
Asset retirement obligation:
Current	$	46	$	46
Non-current	19,404		18,926
Asset retirement obligation, end of period	$	19,450	$	18,972

The asset retirement obligations of the Company are subject to legal and regulatory requirements. Estimates of the costs of reclamation are reviewed periodically by the Company and the applicable regulatory authorities. The above provision represents the Company’s best estimate of the present value of future reclamation costs, discounted using credit adjusted risk-free interest rates ranging from 9.5% to 11.5% and an inflation rate of 2.0%. The total undiscounted decommissioning liability at March 31, 2020 is $41.75 million (December 31, 2019 - $41.75 million).

The following table summarizes the Company’s restricted cash:



	March 31, 2020		December 31, 2019
Restricted cash, beginning of period	$	20,081	$	19,652
Additional collateral posted	45		429
Restricted cash, end of period	$	20,126	$	20,081

The Company has cash, cash equivalents and fixed income securities as collateral for various bonds posted in favor of the applicable state regulatory agencies in Arizona, Colorado, New Mexico, Texas, Utah and Wyoming, and the U.S. Bureau of Land Management and U.S. Forest Service for estimated reclamation costs associated with the White Mesa Mill, Nichols Ranch, Alta Mesa and other mining properties. Cash equivalents are short-term highly liquid investments with original maturities of three months or less. The restricted cash will be released when the Company has reclaimed a mineral property or restructured the surety and collateral arrangements. See Note 14 for a discussion of the Company’s surety bond commitments.

Cash, cash equivalents and restricted cash are included in the following accounts at March 31, 2020 and December 31, 2019:



	March 31, 2020		December 31, 2018
Cash and cash equivalents	$	23,537	$	12,810
Restricted cash included in other long-term assets	20,126		20,081
Total cash, cash equivalents and restricted cash	$	43,663	$	32,891