Provisions (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of provisions [Line Items]

Disclosure of detailed information about provisions [Text Block]

(a)

This caption is made up as follows:

	2017		2016
	US$(000)		US$(000)

Provision for closure of mining units and exploration projects (b)		200,183		206,462
Provision for obligations with communities (c)		19,376		4,710
Provision for environmental liabilities		5,534		7,324
Provision for safety contingencies		3,898		2,807
Provision for labor contingencies		2,963		3,395
Workers’ profit sharing payable		3,569		8,398
Board of Directors’ participation		1,273		1,140
Provision for environmental contingencies		1,233		753
Other provisions		3,695		1,703

		241,724		236,692

Classification by maturity:
Current portion		76,847		62,502
Non-current portion		164,877		174,190

		241,724		236,692

(b)

Provision for closure of mining units and exploration projects -

Disclosure of detailed information about provision for closure of mining units and exploration projects [Text Block]

(b)

Provision for closure of mining units and exploration projects -

The table below presents the movement of the provision for closure of mining units and exploration projects:

	2017		2016
	US$(000)		US$(000)

Beginning balance		206,462		166,403
Transfer of units held for sale		-		15,851
Sale of mining units, note 1(e)		(11,770)		-

Changes and additions in estimates:
Discontinued mining units, note 1(e)		12,701		3,365
Continuing mining units, note 11(a)		10,594		34,532
Exploration projects		891		-

Accretion expense:
Discontinued operations, note 1(e)		215		970
Continuing mining units, note 26(a)		4,382		4,116

Disbursements		(23,292)		(18,775)

Final balance		200,183		206,462

Classification by maturity:
Current portion		39,826		37,405
Non-current portion		160,357		169,057

		200,183		206,462

Minera Yanacocha SRL and subsidiary [member]

Disclosure of provisions [Line Items]

Disclosure of detailed information about provisions [Text Block]

This caption is made up as follows:

	2017		2016
	US$(000)		US$(000)

Provision for closure of mining units and exploration projects (b)		1,234,731		1,012,888
Provision of social responsability		21,689		24,335
Workers’ profit sharing payable (c)		1,733		13,005
Accrual of operating costs		15,064		19,650
Other provisions		3,243		23,809
		1,276,460		1,093,687

Classification by maturity:
Current portion		39,495		68,662
Non-current portion		1,236,965		1,025,025
		1,276,460		1,093,687

Disclosure of detailed information about provision for closure of mining units and exploration projects [Text Block]

The movement of the ARO for 2017, 2016 and 2015 is broken down as follows:

	2017		2016		2015
	US$(000)		US$(000)		US$(000)

Opening balance		1,012,888		578,959		557,457
Additional provisions		221,450		430,292		10,434
Payments		(21,376)		(10,467)		(11,007)
Unwinding of discount, note 19		21,769		14,104		22,075
Final balance		1,234,731		1,012,888		578,959

Classification by maturity
Current portion		19,455		15,636		6,698
Non-current portion		1,215,276		997,252		572,261
		1,234,731		1,012,888		578,959

Sociedad Minera Cerro Verde S.A.A. [Member]

Disclosure of provisions [Line Items]

Disclosure of detailed information about provisions [Text Block]

This item is made up as follows:

	December 31,		December 31,
	2017		2016
	US$(000)		US$(000)

Current:
Provisions related to services and freight not invoiced		14,513		11,231
Provision for social commitments (a)		2,767		11,722
Provision for legal contingencies		1,232		1,505
Provision for remediation and mine closure (b)		690		-

Total current		19,202		24,458

Non–current:
Provision for remediation and mine closure (b)		156,169		153,313
Provision for royalties and mining tax (c)		148,530		-
Provision for interest (d)		18,270		-
Other long-term liabilities (e)		15,889		7,249
Provision for social commitments (a)		8,229		4,060


Total non-current		347,087		164,622

(a)

The provision for social commitments as of December 31, 2017, is associated with an irrigation project in La Joya (US$5.5 million) and repaving Alata-Congata Road (US$5.5 million).

(b)

The Company’s mineral exploitation activities are subject to environmental protection standards. In order to comply with these standards, the Company has obtained the approval for the Environment Adequacy Program (PAMA) and for the Environmental Impact Studies (EIA), required for the operation of Cerro Verde’s production unit.

On October 14, 2003, Law N° 28090 was enacted, which regulates the commitments and procedures that entities involved in mining activities must follow in order to prepare, file and implement a mine site closing plan, as well as the respective environmental guarantees that assure compliance with the plan in accordance with protection, conservation and restoration of the environment. On August 15, 2005, the regulations regarding this law were approved.

During 2006, in compliance with the mentioned law, the Company completed the closure plans for its mine site, and presented it to the Ministry of Energy and Mines. On October 5, 2009, the Ministry of Energy and Mines issued Resolution No 302-2009 MEM-AAA, approving the Company’s mine closure plan. As of December 31, 2017, pursuant to legal requirements, the Company has issued letters of credit to the Ministry of Energy and Mines totaling US$35.5 million to secure mine closure plans.

The estimate of remediation and mine closure costs is based on studies prepared by independent consultants and based on current environmental regulations. This provision corresponds mainly to the activities to be performed in order to restore the areas affected by mining activities. The main tasks to be performed include ground removal, soil recovery, and dismantling of plant and equipment.

(c)

Represents the non-current portion of disputed mining royalties for the period December 2006 through September 2011 of US$127.5 million, net asset tax (ITAN) for the years 2010, 2011 and 2013 of US$19.6 million, penalties of royalties for the period December 2006 to 2008 of US$1.4 million (see Note 18(a)).

(d)

Represent the non-current portion of interest and interest on penalties associated with the installment program of mining royalties for the period December 2006 through the year 2008 (see Note 14(d)).

(e)

Represents prior year SUNAT assessments related to income and non-income tax contingencies in which the Company expects to obtain an unfavorable result of US$11.4 million.

Disclosure of movement in provision for remediation and mine closure [Text Block]

The table below presents the changes in the provision for remediation and mine closure:

	2017		2016
	US$(000)		US$(000)

Beginning balance		153,313		161,270
Accretion expense		4,595		4,391
Changes in estimates, note 8		(3,710)		(16,091)
Additions, note 8		2,661		3,743

Final balance		156,859		153,313