Inventory, net

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Disclosure of inventory net [Line Items]

Inventory, net

(a)

This caption is made up as follows:

	2018			2017
	US$(000)			US$(000)

Finished goods		7,715			6,151
Products in process (b)		73,796			56,190
Spare parts and supplies		81,383			84,787
		162,894			147,128
Provision for impairment of value of inventory (c)		(23,163	)		(11,603	)

		139,731			135,525

Classification by use:
Current portion		135,919			132,287
Non-current portion		3,812			3,238

		139,731			135,525

(b)

Products in process include mineral deposits located in the Tajo Norte mining unit (El Brocal). The detail of this mineral as of December 31, 2018 and 2017 is presented below:

	2018					2017
	US$(000)			DMT		US$(000)			DMT

Mineral in stock piles		5,297			342,411		7,173			463,746
Fresh mineral in plant		32,506			1,818,008		11,983			835,613
Tail mineral		-			-		279			30,110
		37,803			2,160,419		19,435			1,329,469

Provision for impairment of value in mineral classified in process		(1,467	)		-		(1,467	)		-
		36,336			2,160,419		17,968			1,329,469

Classification by use:
Current portion		33,383					14,730
Non-current portion		2,953					3,238
		36,336					17,968

El Brocal´ Management estimates to use the non-current mineral during the years 2019 and 2020, according to the new mining plans prepared by El Brocal.

The provision for impairment of value of inventory had the following movement during the years 2018, 2017 and 2016:

	2018			2017			2016
	US$(000)			US$(000)			US$(000)

Beginning balance		11,603			8,386			20,472

Provision for impairment of finished and in progress goods, note 21(a)		4,640			2,118			-
Reversal for impairment of finished and in progress goods (continuing operations), note 21(a)		(119	)		-			(7,581	)
Provision for impairment of spare parts and supplies, note 26		7,039			2,444			-
Reversal for impairment of spare parts and supplies (discontinued operations), note 1(e)		-			(1,345	)		(706	)
Transfer from mining units held for sale		-			-			1,448
Reversal in provision for impairment of inventories		-			-			(5,137	)
Reversal for impairment of spare parts and supplies, note 26		-			-			(110	)

Final balance		23,163			11,603			8,386

In the opinion of Group’s Management, the provision for impairment of value of inventory adequately covers this risk as of the date of the consolidated statements of financial position.

Minera Yanacocha SRL and subsidiary [Member]

Disclosure of inventory net [Line Items]

Disclosure of inventories [text block]

Inventories, net

(a)

This caption is made up as follows:

	2018			2017
	US$(000)			US$(000)

Precious metals		6,878			15,446
Leach in-circuit		1,835			8,057
Mill in-circuit		4,002			2,048
Materials and supplies		49,327			52,171
		62,042			77,722

Allowance for obsolescence of materials and supplies (b)		(7,515	)		(7,076	)

		54,527			70,646

(b)

The allowance for obsolescence of material and supplies had the following movement during the years 2018, 2017 and 2016:

	2018			2017			2016
	US$(000)			US$(000)			US$(000)

Opening balance		7,076			5,272			5,881
Provision for impairment of materials and supplies		1,887			2,896			3,104
Reversal of provision for impairment of materials and supplies		(1,448	)		(1,092	)		(3,713	)

Ending balance		7,515			7,076			5,272

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

Disclosure of inventory net [Line Items]

Disclosure of inventories [text block]

Inventories, net

This item is made up as follows:

	December 31 , 2018			December 31 , 2017
	US$(000)			US$(000)

Current
Materials and supplies		308,378			273,939
Work-in-process (WIP) (a)		149,975			148,928
Finished goods:
Copper concentrate		17,949			18,068
Copper cathode		8,035			4,032
Molybdenum concentrate		3,205			1,896
Less: Provision for obsolescence of materials and supplies		(11	)		(1,237	)
		487,531			445,626

Non-current
Work-in-process (WIP) (a)		255,918			248,452

Total inventories		743,449			694,078

(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.