NOTE 6 - 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 as support for this obligation. The accepted value of the Lima office building, for this purpose, is $36.9 million. Through June 2018, the Company has provided guarantees of $32.3 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 June 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 initiated a program for plant demolition and soil remediation with a budget of $66.2 million, which has been spent through June 30, 2018. 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 overall cost recognized for mining closure in Mexico includes the estimated costs of dismantling concentrators, smelter and refinery plants, shops and other facilities.

The following table summarizes the asset retirement obligation activity for the six months ended June 30, 2018 and 2017 (in millions):

	2018			2017
Balance as of January 1,	$	222.5		$	216.5
Changes in estimates	(15.6		)	—
Payments	—			(0.3		)
Accretion expense	6.2			6.6

Balance as of June 30,	$	213.1		$	222.8