Mining concessions, development costs, property, plant and equipment, net (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of detailed information about property, plant and equipment [text block]

(a)

Below is presented the movement:

	Balance as of January 1, 2017		Additions		Disposals			Sales			Reclassifications and transfers			Balance as of December 31, 2017		Additions		Disposals			Sales			Reclassifications and transfers			Balance as of December 31, 2018
	US$(000)		US$(000)		US$(000)			US$(000)			US$(000)			US$(000)		US$(000)		US$(000)			US$(000)			US$(000)			US$(000)

Cost
Lands		22,958		-		-			-			(268	)		22,690		783		(462	)		-			(1,250	)		21,761
Mining concessions		198,009		2		-			(15,000	)		(31,138	)		151,873		-		-			-			-			151,873
Development costs		652,392		69,335		-			(10,107	)		431			712,051		32,059		(2,656	)		-			1,805			743,259
Buildings, constructions and other		1,109,167		835		(387	)		(28,751	)		198,387			1,279,251		-		(2,837	)		-			66,207			1,342,621
Machinery and equipment		986,032		2,579		(3,749	)		(50,097	)		(5,742	)		929,023		-		(182	)		(9,205	)		38,830			958,466
Transportation units		10,416		11		(190	)		(1,079	)		788			9,946		42		(138	)		(510	)		1,545			10,885
Furniture and fixtures		14,047		31		(157	)		(487	)		468			13,902		-		-			(193	)		(403	)		13,306
Units in transit		30,051		2,822		-			-			(28,124	)		4,749		11		-			-			(2,078	)		2,682
Work in progress		105,788		173,333		-			(190	)		(177,809	)		101,122		67,096		(3,450	)		-			(108,106	)		56,662
Stripping activity asset (e)		124,467		18,282		(13,573	)		-			1,271			130,447		11,279		-			-			-			141,726
Mine closure costs		247,889		10,594		-			(17,195	)		-			241,288		61,239		-			-			(18,365	)		284,162
		3,501,216		277,824		(18,056	)		(122,906	)		(41,736	)		3,596,342		172,509		(9,725	)		(9,908	)		(21,815	)		3,727,403
Accumulated depreciation and amortization:
Lands		-		-		-			-			1,249			1,249		-		-			-			(1,249	)		-
Mining concessions		77,466		8		-			(13,845	)		(23,390	)		40,239		10		-			-			-			40,249
Development costs		241,636		30,886		-			(7,910	)		(1,490	)		263,122		35,433		-			-			(2	)		298,553
Buildings, construction and other		455,678		73,314		(115	)		(28,208	)		6,168			506,837		84,244		-			-			562			591,643
Machinery and equipment		558,061		74,744		(2,662	)		(41,595	)		(6,099	)		582,449		93,722		(177	)		(8,659	)		(1,978	)		665,357
Transportation units		8,792		837		(114	)		(1,057	)		(68	)		8,390		745		(85	)		(436	)		(15	)		8,599
Furniture and fixtures		9,172		1,109		(152	)		(236	)		(13	)		9,880		644		-			(187	)		(214	)		10,123
Stripping activity asset		18,729		16,343		-			-			6,623			41,695		28,820		-			-			3			70,518
Mine closure costs		141,275		25,254		-			(8,408	)		-			158,121		10,350		-			-			-			168,471
		1,510,809		222,495		(3,043	)		(101,259	)		(17,020	)		1,611,982		253,968		(262	)		(9,282	)		(2,893	)		1,853,513
Provision for impairment of long-lived assets:
Mine closure costs		10,990		17,916		-			(8,785	)		-			20,121		-		(5,693	)		-			(1,221	)		13,207
Development costs		9,487		2,864		-			(2,198	)		-			10,153		-		-			-			-			10,153
Mining concessions, development costs, property, plant and other		9,905		840		-			(6,214	)		-			4,531		-		(2,837	)		-			1,221			2,915
		30,382		21,620		-			(17,197	)		-			34,805		-		(8,530	)		-			-			26,275

Net cost		1,960,025													1,949,555													1,847,615

Commodity price estimates for current and long-term periods [Text Block]

Estimates prices for the current and long-term periods that have been used to estimate future cash flows are as follows:

	2019	2020-2023
	US$	US$

Gold	1,250 /Oz	1,300 /Oz
Silver	16 /Oz	17 /Oz
Copper	6,750 /MT	7,000 /MT
Lead	2,100 /MT	2,100 /MT

Minera Yanacocha S.R.L. [Member]

Disclosure of detailed information about property, plant and equipment [text block]

(a)

Below is presented the movement in cost:

	Opening balance		Additions		Sales and disposals			Transfer/Other changes			Final balances
	US$(000)		US$(000)		US$(000)			US$(000)			US$(000)

Year 2018
Cost-
Land		9,459		-		-			-			9,459
Land improvements		36,454		-		-			-			36,454
Building and constructions		297,798		-		-			530			298,328
Machinery and equipment		286,865		-		(72,442	)		30,137			244,560
Leach pads		1,722,786		-		-			484			1,723,270
Vehicles		11,024		-		(1,171	)		68			9,921
Furniture and fixtures		2,556		-		-			-			2,556
Other equipment		57,773		-		(265	)		1,416			58,924
Work in progress		400,410		117,636		-			(73,358	)		444,688
Mining rights		37,521		-		-			-			37,521
Asset retirement and mine closure		507,123		27,275		-			-			534,398
Stripping activity asset		148,487		-		-			-			148,487
Mine development		722,355		-		-			38,292			760,647

		4,240,611		144,911		(73,878	)		(2,431	)		4,309,213

Accumulated depreciation and amortization
Land improvements		35,143		440		-			-			35,583
Building and constructions		240,348		7,631		-			-			247,979
Machinery and equipment		249,975		20,887		(66,607	)		-			204,255
Leach pads		1,621,266		34,736		-			-			1,656,002
Vehicles		11,024		2		(1,171	)		-			9,855
Furniture and fixtures		2,556		-		-			-			2,556
Other equipment		55,914		828		(220	)		-			56,522
Mining rights		29,457		-		-			-			29,457
Asset retirement and mine closure		356,345		67,663		-			-			424,008
Stripping activity asset		143,252		2,806		-			-			146,058
Mine development		639,450		17,034		-			-			656,484

		3,384,730		152,027		(67,998	)		-			3,468,759

Net cost		855,881										840,454

Commodity price estimates for current and long-term periods [Text Block]

Estimated prices for the current and long-term periods that have were used to estimate future revenues were as follows:

	Current		Long-term
	US$		US$

Gold (per ounce)		1,221		1,300

Sociedads Mineras Cerro Verde Saa [Member]

Disclosure of detailed information about property, plant and equipment [text block]

The changes in cost and accumulated depreciation accounts as of December 31, 2018 and 2017 are shown below:

	January 1, 2017		Additions		Adjustments			Disposals			Transfers			December 31, 2017		Additions		Adjustments			Disposals			Transfers			December 31, 2018
	US$(000)		US$(000)		US$(000)			US$(000)			US$(000)			US$(000)		US$(000)		US$(000)			US$(000)			US$(000)			US$(000)

Cost
Land		23,683		-		-			-			784			24,467		-		-			-			196			24,663
Buildings and other constructions		2,376,961		-		(13,532	)		(1,169	)		7,782			2,370,042		-		41,089			(9,644	)		48,090			2,449,577
Machinery and equipment		4,442,180		-		13,532			(4,540	)		102,336			4,553,508		-		(41,089	)		(19,426	)		201,057			4,694,050
Transportation units		19,110		-		-			(261	)		1,708			20,557		-		-			(32	)		2,726			23,251
Furniture and fixtures		949		-		-			-			-			949		-		-			-			-			949
Other equipment		24,671		-		-			(34	)		340			24,977		-		-			(11	)		525			25,491
Construction in progress and in-transit units		88,766		173,845		-			-			(112,950	)		149,661		288,861		-			-			(252,594	)		185,928
Stripping activity asset (see Note 2(j))		324,759		153,623		-			-			-			478,382		177,327		-			-			-			655,709
Asset retirement costs (see Note 11(b))		137,376		2,661		(3,710	)		-			-			136,327		2,724		(32,017	)		-			-			107,034
		7,438,455		330,129		(3,710	)		(6,004	)		-			7,758,870		468,912		(32,017	)		(29,113	)		-			8,166,652

Accumulated depreciation
Buildings and other constructions		144,862		86,391		(457	)		(1,169	)		-			229,627		96,623		5,184			(9,514	)		-			321,920
Machinery and equipment		1,237,979		283,250		457			(4,349	)		-			1,517,337		292,656		(5,184	)		(18,483	)		-			1,786,326
Transportation units		10,865		1,593		-			(237	)		-			12,221		1,784		-			(33	)		-			13,972
Furniture and fixtures		802		32		-			-			-			834		24		-			-			-			858
Other equipment		13,953		2,474		-			(27	)		-			16,400		2,406		-			(10	)		-			18,796
Stripping activity asset		209,065		76,262		-			-			-			285,327		112,875		-			-			-			398,202
Asset retirement costs		13,189		5,511		-			-			-			18,700		4,976		-			-			-			23,676
		1,630,715		455,513		-			(5,782	)		-			2,080,446		511,344		-			(28,040	)		-			2,563,750
Net cost		5,807,740													5,678,424													5,602,902

(a)

As of December 31, 2018 construction in progress primarily relates to the mine maintenance truck shop (US$

90.6

million), the purchase of stators for ball mills (US$

24.3

million), the purchase of used haul trucks from PT Freeport Indonesia (a related party) (US$

17.2

million) and phase I of the tailing drain expansion (US$

11.9

million).