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Peru

Constancia Mine

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Copper
  • Molybdenum
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
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Mine Life... Lock
SnapshotConstancia is one of the lowest cost open pit copper mines in South America.

The Constancia mine is a traditional open pit shovel/truck operation with two deposits: Constancia and Pampacancha. The operation consists of open pit mining and flotation of sulphide minerals to produce commercial grade concentrates of copper and molybdenum. Silver and a small quantity of payable gold reports to the copper concentrate.

In 2024, Hudbay Minerals increased mineral reserve estimates at Constancia to include the addition of a tenth mining phase in the Constancia pit after conducting positive geotechnical drilling and studies in 2023. This extended the expected mine life at Constancia by three years to 2041 and there is potential for future mine life extensions.

Partially as a result of processing stockpiles to lower fuel consumption in early 2023, the mine life of the Pampacancha deposit has now been extended to the third quarter of 2025.

Owners

SourceSource
CompanyInterestOwnership
Hudbay Minerals Inc. 100 % Indirect
Hudbay Peru SAC (operator) 100 % Direct
Hudbay owns and operates 100% of the Constancia mine through its wholly-owned subsidiary HudBay Peru S.A.C.

Contractors

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Deposit type

  • Porphyry
  • Vein / narrow vein
  • Skarn
  • Epithermal

Summary:

Constancia mine include the Constancia and Pampacancha deposits

The Constancia deposit is a porphyry copper-molybdenum system which includes copper-bearing skarn mineralization. Multiple phases of monzonites and monzonite porphyry have intruded a sequence of sandstones, mudstones and micritic limestone of Cretaceous age.

The majority of the mineralization is associated with potassic alteration and quartz veining, occurring as chalcopyrite-(bornite)-molybdenite-pyrite mineralization in “A” and “B” type veinlets, and replacing ferromagnesian minerals or filling fractures. Copper grades are highest where fracture-filling style copper mineralization is superimposed on earlier disseminated copper mineralization. The higher-grade hypogene copper mineralization is hosted by a dense A-veinlet stockwork developed in an early porphyry phase. The pyrite/chalcopyrite ratio is typically below 2:1. Molybdenite commonly increases with depth in association to “B” veinlets. Bornite occurs sporadically especially at deeper levels, sometimes associated with some gold values.

Propylitic alteration is transitional to the potassic alteration and extends more than one kilometre from the porphyry intrusive contacts. The propylitic alteration mineral assemblage includes epidote-chlorite-calcitepyrite-rhodochrosite. Subordinate chalcopyrite is also present, filling fractures or replacing mafic minerals. Sphalerite-galena veinlets and veins are distributed as a halo to the copper-molybdenum mineralization within the propylitic alteration zone up to 3 km away from the porphyry copper system.

Phyllic alteration forms a pervasive carapace surrounding and sometimes overprinting potassic alteration. The phyllic alteration accompanies almost complete destruction of primary rock textures; the mineral assemblage includes sericite-quartz-pyrite, limited amounts of chalcopyrite and associated occasional “D” veins and veinlets.

At the contact between intrusions and limestones, a magnetite garnet skarn develops, while a pyroxene– diopside (garnet–epidote) association is more common in calcareous sandstones and arkoses of the Chilloroya formation. Skarn mineralization is volumetrically much smaller, but grades are normally higher.

Structural deformation has played a significant role in concentrating the hydrothermal alteration and the copper-molybdenum-silver-gold mineralization, including skarn formation. Major inter and post mineral fracture systems in the deposit area strike northeast and include the Barite fault system. This is represented by a number of nearly parallel vein-faults carrying base metal sulphides and barite which have been exploited by artisanal workings throughout the property. A second important system strikes northsouth. It appears to be more recent than the Barite system and controls part of mineralization and most of the silicified breccias (sometimes mineralized) in the system.

The Pampacancha deposit is a porphyry Cu-Mo-Au related Skarn system. Oligocene unmineralized basement diorite is intruded by the diorite porphyry cited as the source for skarn mineralization. This in turn is cut by intra-mineral monzonite intrusions which provide minor local increases in Cu-Au and also locally replaces skarn Cu-Au mineralization which is most developed at the upper and lower margins of the limestone body. Magnetite-chalcopyrite-pyrite skarn ranges to marginal less well mineralized garnet and pyroxene skarn, locally overprinted by epidote-bearing retrograde skarn.

Epithermal mineralization as low sulphidation quartz-sulphide Au + Cu style accounts for common supergene enriched Au anomalies along with other features such as hydrothermal alteration and veins typical of near porphyry locations.

The Constancia porphyry copper-molybdenum system, including skarn, exhibits five distinct deposit types of mineralization:
1. Hypogene fracture-controlled and disseminated chalcopyrite mineralization in the monzonite (volumetrically small);
2. Hypogene chalcopyrite (rare bornite) mineralization in the skarns (significant);
3. Supergene digenite-covellite-chalcocite (rare native copper) in the monzonite (significant);
4. Mixed secondary sulphides/chalcopyrite in the monzonite (significant); and 5. Oxide copper mineralization (volumetrically small).

Molybdenite, gold and silver occur within all these mineralization types.

Two areas of porphyry-style mineralization are known within the project area, Constancia and San José. At Constancia, mineralization is deeper than that observed at San José which occurs at surface. The mineralized zone extends about 1,200 metres in the north-south direction and 800 metres in the east- west direction.

The Pampacancha deposit is located approximately three kilometers southeast of the Constancia porphyry. The stratigraphy unit in the area is the massive, gray micritic limestone of Upper Cretaceous Ferrobamba Formation; this unit in contact with the dioritic porphyry generates a magnetite skarn, hosts economic mineralization of Cu-Au-Mo.

The intrusive rocks are Oligocene age unmineralized basement diorite. Diorite porphyry is recognized as the source for skarn mineralization, which in turn is cut by mineralized monzonite intrusions which provide minor local increases in Cu-Au mineralization. Skarn Cu-Au mineralization is best developed at the upper and lower margins of the limestone body.

Epithermal mineralization of the low sulphidation quartz-sulphides Au + Cu style, accounts for common supergene enriched Au anomalies, and along with other features such as hydrothermal alteration and veins typical of near porphyry settings.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityProductUnits2024202320222021202020192018201720162015
Copper Metal in concentrate t  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe113,825122,178121,781133,432105,897
Molybdenum Metal in concentrate t  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,272904454
Gold Metal in concentrate oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe19,72324,18917,57926,27618,839
Silver Metal in concentrate oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe2,504,7692,729,8592,374,0082,760,3321,989,664
Copper Concentrate kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe488513480527399
^ Guidance / Forecast.

Operational metrics

Metrics202320222021202020192018201720162015
Daily milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe90 kt90 kt
Annual milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Stripping / waste ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe33,308,369 t34,372,156 t29,982,808 t26,519,954 t25,828,849 t
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe31,387,281 t31,282,610 t28,743,952 t27,032,775 t23,522,010 t
Annual processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Annual mining capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Daily milling rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe86 kt86 kt79 kt74 kt80 kt

Production Costs

CommodityUnits20242023202220212020201920182017
Credits (by-product) Copper USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe -0.23 / lb   -0.18 / lb   -0.09 / lb  
Cash costs Copper USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1.64 / lb   1.54 / lb   1.37 / lb  
Cash costs Copper USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1.41 / lb **   1.36 / lb **   1.28 / lb **  
All-in sustaining costs (AISC) Copper USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1.9 / lb **   1.59 / lb **  
^ Guidance / Forecast.
** Net of By-Product.

Operating Costs

Currency20232022202120202019201820172016
Total operating costs ($/t milled) USD 12.5  12.8  11.4  9.46  9.5  9.44  8.83  8.09  

Financials

Units20242023202220212020201920182017
Capital expenditures (planned) M USD  ....  Subscribe
Growth Capital M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 84.9   40   123.8  
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 87   42.3   137.8  
Gross profit M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 134.7   240.7  

Heavy Mobile Equipment

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Personnel

Mine Management

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EmployeesYear
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Aerial view:

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