Asset Retirement Obligations

9 Months Ended

Sep. 30, 2019

Asset Retirement Obligation Disclosure [Abstract]

The Company's asset retirement obligations are principally for costs to close its surface mines and reclaim the land it has disturbed as a result of its normal mining activities as well as for costs to dismantle certain mining equipment at the end of the life of the mine. A reconciliation of the Company's beginning and ending aggregate carrying amount of the asset retirement obligations are as follows:



	Asset Retirement Obligations
Balance at December 31, 2018	$	37,703
Liabilities settled during the period	(4,559		)
Accretion expense	1,888
Revision of estimated cash flows	159
Balance at September 30, 2019	$	35,191

During the second quarter of 2019, the Company transferred the mine permits for certain Centennial mines to an unrelated third party. As a result of these transfers, the Company was relieved of the associated mine reclamation obligations and recorded a $5.4 million reduction to Centennial's asset retirement obligation, $2.4 million of which is reflected as "Liabilities settled during the current period" and $3.0 million of which is reflected as "Revisions in estimated cash flows" in the table above. As part of these transactions, the Company transferred a $3.4 million escrow account and paid $2.4 million of cash, resulting in a net loss on the transactions of $0.4 million recognized within cost of sales in the Unaudited Condensed Consolidated Statement of Operations. The reduction to the asset retirement obligation related to the Centennial transfers was offset by a $3.1 million increase to the asset retirement obligation related to MLMC due to updated cost estimates and changes in timing. This increase is reflected as "Revisions in estimated cash flows" in the table above.