XML 272 R258.htm IDEA: XBRL DOCUMENT
v3.19.1

Embedded derivatives (Details) DMT_Number in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($) DMT_Number | Dec. 31, 2017 USD ($) DMT_Number
Disclosure Of Embedded derivatives [Line Items] |  |
Derivative financial asset liabilities | $ (20,113,000) | $ 68,736,000
Copper cathode [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Quantity of Metal | DMT_Number | 7,711 | 2,756
Embedded derivatives,maturity | January 2019 | January 2018
Provisional pricing | $ 2,810 |
Forward pricing | 2.704 | 3.274
Derivative financial asset liabilities | $ (824,000) | $ 179,000
Copper concentrate [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Quantity of Metal | DMT_Number | 261,530 | 252,830
Embedded derivatives,maturity | January 2019 to May 2019 | January 2018 to May 2018
Derivative financial asset liabilities | $ (18,848,000) | $ 62,870,000
Molybdenum [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Quantity of Metal | DMT_Number | 3,545 | 3,340
Embedded derivatives,maturity | January 2019 to February 2019 | January 2018 to February 2018
Forward pricing | 10.675 | 8.950
Derivative financial asset liabilities | $ (441,000) | $ 5,687,000
Bottom of range [member] | Copper cathode [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing |  | 2,970
Bottom of range [member] | Copper concentrate [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing | $ 2,675 | $ 2,903
Forward pricing | 2.704 | 3.274
Bottom of range [member] | Molybdenum [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing | $ 10,787 | $ 7,229
Top of range [member] | Copper cathode [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing |  | 3,246
Top of range [member] | Copper concentrate [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing | $ 2,834 | $ 3,166
Forward pricing | 2.708 | 3.297
Top of range [member] | Molybdenum [Member] |  |
Disclosure Of Embedded derivatives [Line Items] |  |
Provisional pricing | $ 10,810 | $ 7,231

X
- Definition The amount of derivative financial assets(liabilities) + References No definition available. + Details
Name: | cik0001013131_DerivativeFinancialAssetLiabilities
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | cik0001013131_DisclosureOfEmbeddedDerivativesLineItems
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The description of maturity of embedded derivatives. + References No definition available. + Details
Name: | cik0001013131_EmbeddedDerivativesmaturity
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The forward pricing quotation received from suppliers. + References No definition available. + Details
Name: | cik0001013131_ForwardPricing
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition The provisional pricing quotation received from suppliers. + References No definition available. + Details
Name: | cik0001013131_ProvisionalPricing
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The volume of commodities. + References No definition available. + Details
Name: | cik0001013131_QuantityOfMetal
Namespace Prefix: | cik0001013131_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | cik0001013131_TypesOfCommodityAxis=cik0001013131_CopperCathodeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cik0001013131_TypesOfCommodityAxis=cik0001013131_CopperConcentrateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cik0001013131_TypesOfCommodityAxis=cik0001013131_MolybdenumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |