Inventory, net (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of inventory net [Line Items]

Disclosure of Detailed Information of Inventories [Text Block]

This caption is made up as follows:

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

Finished goods		6,151		12,763
Products in process		56,190		66,651
Spare parts and supplies		84,787		63,946
		147,128		143,360
Provision for impairment of value of inventory (b)		(11,603)		(8,386)

		135,525		134,974

Classification by use:
Current portion		132,287		120,947
Non-current portion		3,238		14,027

		135,525		134,974

Disclosure Of Detailed Information About Mineral Deposits Inventory [Text Block]

Products in process include mineral deposits located in the Tajo Norte mining unit (El Brocal). The detail of this mineral as of December 31, 2017 and 2016 is presented below:

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

Mineral in stock piles		7,173		463,746		16,793		1,085,696
Fresh mineral in plant		11,983		835,613		1,248		74,260
Tail mineral		279		30,110		203		24,629
		19,435		1,329,469		18,244		1,184,585
Provision for impairment of value in mineral classified in process		(1,467)		-		(123)		-

		17,968		1,329,469		18,121		1,184,585

Classification by use:
Current portion		14,730				5,586
Non-current portion		3,238				12,535

		17,968				18,121

Disclosure of impairment of assets [text block]

The provision for impairment of value of inventory had the following movement during the years 2017, 2016 and 2015:

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

Beginning balance		8,386		20,472		7,735

Transfer from mining units held for sale		-		1,448		-
Changes in provision for impairment of finished goods, (continuing operations), note 21(a)		2,118		(7,581)		13,096
Changes in provision for impairment of finished goods (discontinued operations), note 1(e)		(1,345)		(706)		(1,474)
Changes in provision for impairment of spare parts and supplies		2,444		(110)		1,115
Reversal in provision for impairment of inventories		-		(5,137)		-

Final balance		11,603		8,386		20,472

Minera Yanacocha SRL and subsidiary [Member]

Disclosure of inventory net [Line Items]

Disclosure of Detailed Information of Inventories [Text Block]

This caption is made up as follows:

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

Precious metals		15,446		15,012
Leach in-circuit		8,057		6,378
Mill in-circuit		2,048		2,493
Materials and supplies		52,171		52,687
		77,722		76,570

Allowance for obsolescence of materials and supplies (b)		(7,076)		(5,272)
		70,646		71,298

Disclosure of detailed information about allowance for obsolescence of material and supplies [Text Block]

The allowance for obsolescence of material and supplies had the following movement during the years 2017, 2016 and 2015:

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

Opening balance		5,272		5,881		4,832
Provision for impairment of materials and supplies		2,896		3,104		5,060
Reversal of provision for impairment of materials and supplies		(1,092)		(3,713)		(4,011)
Ending balance		7,076		5,272		5,881

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

Disclosure of inventory net [Line Items]

Disclosure of Detailed Information of Inventories [Text Block]

This item is made up as follows:

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

Current
Materials and supplies		273,939		251,635
Work-in-process (WIP) (a)		148,928		148,178
Finished goods:
Copper concentrate		18,068		15,073
Copper cathode		4,032		8,220
Molybdenum concentrate		1,896		2,763
Less: Provision for obsolescence of materials and supplies		(1,237)		(303)
Total current		445,626		425,566

Non-current
Work-in-process (WIP) (a)		248,452		300,614

Total inventories		694,078		726,180

(a)

Work-in-process inventories represent mill and leach stockpiles which contain higher grade ores (mill stockpiles) and medium and lower grade ores (leach stockpiles) that have been extracted from the open pit and are available for copper recovery. Based on the future mine plan production, the Company identifies the portion of inventory that is classified as current or long term. For mill stockpiles, recovery is through milling and concentrating. For leach stockpiles, recovery is through exposure to acidic solutions that dissolve copper and deliver it in a solution to extraction processing facilities.