XML 29 R15.htm IDEA: XBRL DOCUMENT
v3.19.1

Inventory, net | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Disclosure of inventory net [Line Items] |  |
Disclosure of inventories [text block] |
| 8. | 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.
| c) | 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$(000) |
Beginning balance |  |  | 11,603 |  |  |  | 8,386 |  |  |  | 20,472 |
Provision for impairment of finished and in progress goods, note 21(a) |  |  | 4,640 |  |  |  | 2,118 |  |  |  | - |
Reversal for impairment of finished and in progress goods (continuing operations), note 21(a) |  |  | (119 | ) |  |  | - |  |  |  | (7,581 | )
Provision for impairment of spare parts and supplies, note 26 |  |  | 7,039 |  |  |  | 2,444 |  |  |  | - |
Reversal for impairment of spare parts and supplies (discontinued operations), note 1(e) |  |  | - |  |  |  | (1,345 | ) |  |  | (706 | )
Transfer from mining units held for sale |  |  | - |  |  |  | - |  |  |  | 1,448 |
Reversal in provision for impairment of inventories |  |  | - |  |  |  | - |  |  |  | (5,137 | )
Reversal for impairment of spare parts and supplies, note 26 |  |  | - |  |  |  | - |  |  |  | (110 | )
Final balance |  |  | 23,163 |  |  |  | 11,603 |  |  |  | 8,386 |
In the opinion of Group’s Management, the provision for impairment of value of inventory adequately covers this risk as of the date of the consolidated statements of financial position.
Minera Yanacocha SRL and subsidiary [Member] |  |
Disclosure of inventory net [Line Items] |  |
Disclosure of inventories [text block] |
| 7. | Inventories, net
| (a) | This caption is made up as follows:
|  | 2018 |  |  | 2017 |
|  | US$(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] |  |
| 5. | 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.

X
- References No definition available. + Details
Name: | cik0001013131_DisclosureOfInventoryNetLineItems
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for inventories. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 2 -IssueDate 2018-01-01 -Section Disclosure -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2018-03-01&anchor=sect_Disclosure&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_DisclosureOfInventoriesExplanatory
Namespace Prefix: | ifrs-full_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_SignificantInvestmentsInAssociatesAxis=cik0001013131_MineraYanacochaSrlAndSubsidiaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInAssociatesAxis=cik0001013131_SociedadMineraCerroVerdeSaaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |