NOTE 9 -ASSET RETIREMENT OBLIGATION:

The Company maintains an asset retirement obligation for its mining properties in Peru, as required by the Peruvian Mine Closure Law. In accordance with the requirements of this law the Company’s closure plans were approved by the Peruvian Ministry of Energy and Mines (“MINEM”). As part of the closure plans, the Company is required to provide annual guarantees over the estimated life of the mines, based on a present value approach, and to furnish the funds for the asset retirement obligation. This law requires a review of closing plans every five years. Currently and for the near-term future, the Company has pledged the value of its Lima office complex and a warehouse in Lima as support for this obligation. The accepted values of these facilities, for this purpose, are of $45.3 million. Through January 2019, the Company has provided guarantees of $37.8 million. The closure cost recognized for this liability includes the cost, as outlined in its closure plans, of dismantling the Toquepala and Cuajone concentrators, the Ilo smelter and refinery, and the shops and auxiliary facilities at the three units. In March 2016, MINEM approved the Mining Closure Plan for the Toquepala expansion project. The closure plan for the Tia Maria project was approved in February 2017. The Company, however, has not recorded a retirement obligation for the project as the construction permit has not been received, and work on the project is on hold. The Company believes that under these circumstances the recording of a retirement obligation is not appropriate. In accordance with requirements of Peruvian law, the Company in December 2017 and February 2018, submitted to MINEM revised closure plans for the Cuajone mine and the Ilo facilities respectively, which at September 30, 2018 are pending approval. As a result of these new estimates, the Company has reduced the asset retirement obligation by $11.6 million in December 2017 and $5.2 million in the first quarter of 2018.

In 2010, the Company announced to the Mexican federal environmental authorities its closure plans for the copper smelter plant at San Luis Potosi. The Company developed a program for plant demolition and soil remediation with a cost of $66.2 million. In 2016, the environmental authorities approved the conclusion of the remediation effort. The Company continues studying the possibilities for this property in order to decide whether to sell or develop the property. The Company has recognized an estimated asset retirement obligation for its mining properties in Mexico as part of its environmental commitment. Even though there is currently no enacted law, statute, ordinance, written or oral contract requiring the Company to carry out mine closure and environmental remediation activities, the Company believes that a constructive obligation presently exists based on the remediation requirements caused by the closure of any facility. The overall cost recognized for mining closure in Mexico includes the estimated costs of dismantling concentrators, smelter and refinery plants, shops and other facilities. During 2018, the Company made a change in the estimate for the asset retirement obligation in its Mexican operations, mainly due to a change in the discount rate used to determine such obligation. The effect of this change was a reduction in the asset retirement obligation of $10.4 million, which was recorded in the second quarter of 2018.

The following table summarizes the asset retirement obligation activity for years ended December 31, 2018 and 2017 (in millions):


	2018		2017
Balance as of January 1	$	222.5	$	216.5
Changes in estimates		(15.6)		(11.6)
Additions		—		—
Closure payments		(0.6)		(0.3)
Accretion expense		11.4		17.9
Balance as of December 31,	$	217.7	$	222.5