Chile

Escondida Mine

Click for more information

Categories

Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Copper
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life... Lock
SnapshotEscondida in Chile is the world’s largest copper mine. Escondida’s two pits feed three concentrator plants, as well as two leaching operations (oxide and sulphide).

Owners

SourceSource
CompanyInterestOwnershipInvestor's Info
Jeco 2 Ltd. 2.5 % Indirect
JECO Corp. 10 % Indirect
Rio Tinto plc 30 % Indirect
BHP Group Ltd. 57.5 % Indirect
Minera Escondida Ltda. (operator) 100 % Direct
Minera Escondida Limitada operates the Escondida property. Current ownership, which has been stable since 2010 is BHP (57.5%), Rio Tinto (30%), JECO Corporation (10%) and JECO 2 Limited (2.5%).

Minera Escondida Limitada holds mining concessions in accordance with the current mining laws and national constitution of Chile.

Contractors

Lock

- subscription is required.

Deposit type

  • Porphyry

Summary:

Both Escondida and Escondida Norte are porphyry copper deposits, being the deposit type typical of the majority of Chilean/Andean copper deposits. The deposits lie in the Escondida-Sierra de Varas shear lens of the Domeyko Fault System. The deposits are supergene-enriched copper porphyries with primary mineralisation associated with multiple phase intrusions of monzonite to granodiorite composition into host volcanics. The deposits are related geographically and geologically to porphyry bodies intruded along a regional lineament which exerts strong control over the regional distribution of deposits of this age and type.

The Escondida cluster is formed by the Escondida (including Escondida Este) and Escondida Norte - Zaldívar porphyry copper deposits. The latter corresponds to the same ore body mined by two different companies and operations. Additionally, the porphyry copper deposits of Chimborazo and Pampa Escondida, as well as Pinta Verde, have been recognised.

Escondida Deposit
Alteration and Hypogene Mineralisation
Much of the feldspathic porphyry shows sericitic alteration in shallow levels already exploited an advanced argillic zone and at deeper only along fault zones. Quartz, pyrophyllite and subordinate alunite, diaspore, and svanbergite are reported (Brimhall et al., 1985; Alpers and Brimhall, 1988). At depth and as remnants in the sericitic zone, patches of chlorite-sericite alteration exist, which give way downward to biotite in andesitic volcanic rocks and k-feldspar > biotite in the porphyries (Padilla-Garza et al., 2001). The superimposed potassic and sericitic alteration contains abundant A and B type quartz veinlets. The Granodiorita Verde unit shows a weak potassic alteration in veinlets with a generalised chlorotic overprint within which the remaining hydrothermal k-feldspar stands out. The Intermineral Porphyry unit presents diverse alteration associations with variable intensities and showing as a characteristic element, the truncation of veinlets. In some sectors of the pit, there is a marked superimposition of hydrothermal events that originate an intense obliteration on the primary texture, leaving only some quartz relics, which evidence the presence of the intermineral unit (Technical Note, SI Geology, 2021). This unit can be presented primarily with a Chlorite - Sericite - Illite association (Event 1) or affected by superimposition of hydrothermal events such as Sericite - Quartz (Event 2), Sericite (Event 3) and Pyrophyllite - Alunite or Pyrophyllite (Event 4).

The hypogene sulphide mineralisation at Escondida is obliterated by the effects of the supergene enrichment. However, chalcopyrite and bornite are identified in relict potassic zones along with chalcopyrite and pyrite from the overprinted chlorite-sericite and sericite zones. The high sulphidationmineralisation occur in the advanced argillic zone. In the underlying Green Granodiorite intrusion, pyrite dominates over chalcopyrite and copper grades are 0.05 to 0.25%, decreasing at depth.

Supergene Mineralisation
Escondida is characterised by a mature supergene profile with high kaolinite contents, which include a hematitic leaching layer, with an average thickness of ~ 200 m, but locally, can reach 400 m. This leaching zone is supported by a NW-trending enrichment zone that covers an area of 4.5 × 1.8 km with a maximum thickness of ~ 400 m. NW-trending faults, fractures, and veins intersecting the NW trend combined with higher hypogene copper contents appear to have been the main controls on both the shape and depth of the enrichment zone (Ojeda, 1986, 1990; Padilla-Garza et al., 2001). The zone is dominated by chalcocite-group minerals in its higher grade upper part with lower-grade covellite and hypogene sulphides remaining that become dominant at depth. The supergene event is dated between ~ 18 to 14 Ma (Alpers and Brimhall, 1988) in supergene alunite at the limit of the leaching and enrichment zone.

Copper oxide mineralisation at Escondida is mainly found in andesitic volcanic rocks altered with biotite and chlorite-sericite in which brochantite and antlerite are the main minerals along with minor chrysocolla, atacamite, various copper phosphate minerals, cuprite, and native copper with the last two being concentrated in the upper part of the enrichment zone.

Escondida Norte Deposit
Alteration and Hypogene Mineralisation
Potassic alteration is present at depth throughout the deposit, with biotite-feldspar-K association in the felsic rocks and biotite and minor magnetite predominate in the andesitic volcanic rocks and diorites. The potassic alteration have biotite and magnetite veinlets and abundant feld-K and quartz-feldspar-K veinlets,the latter of A-type. Grey sericite veinlets overlie the potassic zone.

At shallower levels, the generalised alteration is chlorite-sericite, which is characterised by the occurrence of chlorite-sulphide veinlets overlaying and destroying the potassic association. This is covered by a sericitic zone, which is locally overlain by quartz-pyrophyllite ± alunite alteration, closely associated with the NW-directed high sulphidation vein zones. Most of the hypogene sulphide mineralisation at Escondida Norte consists of chalcopyrite and pyrite with the development of only localised centres of chalcopyrite - bornite ± chalcocite mineralisation in the potassic zone.

Supergene Mineralisation
A well-developed supergene profile is present at Escondida Norte, which include a leached hematitic surface, averaging 100 to 200 m (up to 350 m) thick, and a 20 to 250 m thick enrichment zone. The enrichment zone has a surface of 2 × 1.5 km, trending NE; it is divided into a high-grade, chalcocite-dominated upper zone (High Enriched), and a lower-grade basal part with covellite and lower chalcocite (Low Enriched). Supergene kaolinite is present throughout the zone and supergene alunite is dated to be ~ 17 to 14 Ma (Morales, 2009).

Copper oxide mineralisation is irregularly developed above the enrichment zone, mainly with antlerite and brochantite in the higher-grade central parts (Maturana and Saric, 1991; Monroy, 2000; Williams, 2003), and chrysocolla and atacamite peripherally.

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Comminution

Crushers and Mills

Lock

- subscription is required.

Processing

Lock

- subscription is required.

Production

CommodityProductUnits2024202320222021202020192018201720162015
Copper Total kt  ....  Subscribe
Copper Cathode kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe253288232330310
Copper Metal in concentrate kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe882926540649916
Gold Metal in concentrate koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe28622911110982
Silver Metal in concentrate koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe8,8308,7964,3265,5614,786
^ Guidance / Forecast.

Operational metrics

Metrics20232022202120202019201820172016
Daily milling capacity  ....  Subscribe  ....  Subscribe
Annual production capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe350 kt of copper cathode350 kt of copper cathode350 kt of copper cathode350 kt of copper cathode
Total tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe417,469 kt416,411 kt
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe125,566 kt118,275 kt
Annual milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe153.7 Mt153.7 Mt153.7 Mt153.7 Mt
Daily mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1.2 Mt

Production Costs

Commodity production costs have not been reported.

Financials

Units2023202220212020201920182017
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,036   997   999  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 6,876   8,774   4,576  
After-tax Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,360   2,221   516  
EBIT M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
EBITDA M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 3,384   4,921   2,397  
Operating Cash Flow M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe

Heavy Mobile Equipment

Lock

- subscription is required.

EV - Electric
AV - Autonomous

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Oct 26, 2023
....................... Subscription required ....................... Subscription required Subscription required Oct 26, 2023
....................... Subscription required ....................... Subscription required Subscription required Oct 26, 2023
....................... Subscription required ....................... Subscription required Subscription required Oct 26, 2023
....................... Subscription required ....................... Subscription required Subscription required Oct 26, 2023

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required 2015

Aerial view:

Lock

- subscription is required.