RECLAMATION

Reclamation and mine closure costs are based principally on legal and regulatory requirements. Management estimates costs associated with reclamation of mining properties. On an ongoing basis, management evaluates its estimates and assumptions, and future expenditures could differ from current estimates.

Changes to the Company’s asset retirement obligations for its operating sites are as follows:



	Year ended December 31,
In thousands	2018			2017
Asset retirement obligation - Beginning	$	118,799		$	86,754
Accretion	11,037			8,769
Additions and changes in estimates	6,880			25,370
Settlements	(3,208		)	(2,094		)
Asset retirement obligation - Ending	$	133,508		$	118,799

The Company accrued $2.0 million at December 31, 2017 and 2018, for reclamation liabilities related to former mining activities, which are included in Reclamation.

During the year ended December 31, 2018, the Company increased the reclamation liability at Silvertip by $6.5 million mainly due to an extended duration of post operational water treatment.

During the year ended December 31, 2017, the Company increased the reclamation liability at Palmarejo by $17.1 million due to the inclusion of the waste rock facility closure plan and tailings facility expansion and at Rochester by $1.2 million at December 31, 2017 due to leach pad expansion. The Company has also recorded a $7.1 million reclamation liability in conjunction with the Silvertip acquisition.