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Peru

Shahuindo Mine

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
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Mine Life... Lock
SnapshotShahuindo is an open-pit, heap leach gold mine, producing silver by products from doré, significant exploration potential exists to extend mine life.

Sustaining capital in 2024 is primarily related to waste dump preparation, heap leach pad expansions and construction of a water treatment plant.

Owners

SourceSource
CompanyInterestOwnership
Pan American Silver Corp. 100 % Indirect
Shahuindo S.A.C. (operator) 100 % Direct
The Shahuindo mine is 100% owned and operated by Pan American’s wholly owned subsidiary, Shahuindo S.A.C.

Contractors

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Deposit type

  • Epithermal
  • Sediment-hosted

Summary:

The Property is located within a regional fold and thrust belt of predominantly Mesozoic sedimentary rocks intruded by felsic stocks located along faults and cores of anticlinal structures. Sedimentary rocks of Lower Cretaceous age consist of a lower, shallow marine-to-deltaic siliciclastic sequence and an upper sequence of finer grained siliciclastic units.

The oldest rocks on the Property are thinly bedded and laminated mudstones with occasional coal seams of the basal Lower Cretaceous Chicama Formation. This formation is only exposed in valleys and in the cores of anticlines.

Overlying the Chicama Formation is the Goyllarisquizga Group, which is comprised from oldest to youngest of the Chimu, Santa, Carhuaz, and Farrat Formations.

White orthoquartzite beds of the Chimu formation form the Algamarca anticline to the southwest of the Shahuindo deposit. The Santa Formation which is exposed on the flanks of the Algamarca anticline consists of mudstone with intercalations of limestone. Overlying the Santa Formation is the Carhuaz Formation, consisting of interbedded sandstone, siltstone, and mudstone, with many sandstones displaying cross bedding and amalgamated wedge-shaped sandstone beds. The Farrat Formation consists of cliff-forming siliciclastic strata dominated by sandstone. The Carhuaz Formation hosts gold and silver mineralization along the core of the Shahuindo deposit while the Farrat Formation hosts mineralization along the northwest, northeast, and southeast flanks.

Multiple intrusions have intruded the Cretaceous sedimentary sequence at Shahuindo. Intrusions include rocks described as andesite, dacite porphyry, and intrusion breccia. Compositions vary from diorite porphyry (known as “andesite” in the district) to dacite porphyry, fine-grained dacite porphyry, quartz diorite porphyry, and foliated quartz diorite porphyry. The three intrusive breccia phases are heterolithic breccia with biotite diorite matrix, heterolithic breccia with fine-grained dacite matrix, and heterolithic megabreccia with foliated quartz-biotite dacite matrix.

Diorite porphyry (andesite) observed in the southeast part of the Property corridor formed as sills in the Goyllarisquizga Group sediments. It is characterized by large (8 mm diameter) biotite phenocrysts, a lack of quartz, and no evidence of hydrothermal alteration. An isotopic age determination is reported to have been made (thought to be zircon U-Pb) on this intrusion that yielded an age of ~26 Ma (Bussey and Nelson, 2011).

The dacite porphyry is the most widespread intrusive in the district that forms a commonly argillically altered dike-like body with relatively steep discordant contacts in the north part of the main corridor that splays into a series of narrow dikes to the southeast. The dacite porphyry is thought to have been emplaced as sills concordant to Goyllarisquizga Group sediment bedding. An isotopic age determination (zircon U-Pb) of this intrusive yielded an age of ~16 Ma (Bussey and Nelson, 2011).

Three intrusive breccia phases are recognized on the Property and include; (1) heterolithic biotite diorite breccia, (2) heterolithic fine-grained dacite breccia, and (3) heterolithic megabreccia. Heterolithic finegrained dacite breccia occurs as narrow (< 3 m width) dike-like bodies with rounded to subangular clasts (up to 10 centimetres (cm) in diameter) of sandstone, siltstone, dacite porphyry, and rare shale in a matrix of fine-grained lithic clasts and clay with 1 - 3 mm quartz, biotite, and plagioclase crystals.

Mineralization
The principal zone of mineralization in the Shahuindo district occurs in a belt between two large-amplitude regional-scale folds, the Algamarca anticline and the San Jose Anticline. The Algamarca anticline is upright and symmetrical with amplitude of at least 400 m, whereas the San Jose fold is an asymmetric, overturned, northeast-vergent fold with a shallowly dipping axial surface and amplitude of at least 300 m. Important structural elements include fold limbs and fold axial surfaces, fold-related fractures, faults and related extension fractures, breccia dikes and irregular bodies, and igneous intrusive contacts.

Mineralization at Shahuindo has been identified over an area approximately 3.7 km southeast to northwest and 0.5 km southwest to northeast. Oxidation of mineralization extends to a depth of 150 m below surface. Sulfide mineralization has been identified by surface drilling to 700 m depth.

Mineralization at Shahuindo can best be described as an intermediate-sulfidation epithermal system, though high-sulfidation mineralization occurs at depth and in the core of hydrothermal breccias. The highsulfidation mineralization was pervasively overprinted by intermediate-sulfidation mineralization (pyrite, galena, sphalerite, Ag sulfosalts), which occurs at shallow levels and in “feeder structures”. Mineralization occurs on fracture surfaces, in breccia matrix, and as disseminations within the sediment packages.

The host rocks at Shahuindo are the Carhuaz and Farat sedimentary formations which are folded and locally fault offset, and cut by porphyritic dikes and stocks. Sandstone tends to be a better host to higher grades of gold and silver compared to siltstone. Brecciated structures with polylithic fragments consist of wall rock clasts, locally clasts of residual quartz (the vuggy texture indicating rock dissolution), as well as juvenile clasts of dike rock, the latter evidence of a syn-hydrothermal timing of dike emplacement.

In the oxide facies, which is interpreted to be the result of weathering processes, gold and silver are associated with the presence of jarosite and hematit. In the sulfide facies, gold is typically extremely fine-grained and the mineral species has not been identified. Fine-grained pyrite forms a close association with gold mineralization and occurs as disseminations, veinlets, and semi-massive replacement bodies.

Tetrahedrite, sphalerite, galena, arsenopyrite, stibnite, and covellite have also been reported as minute blebs adhering to zoned pyrite. Although native silver has been identified at San José and in the historic Shahuindo mine, silver is usually found in sulfosalts at Shahuindo.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

CommodityUnits202420232022202120202019201820172016
Gold koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe145847948
Silver koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe13711654
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.

Operational metrics

Metrics2023202220212020201920172016
Daily processing rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe36,000 t
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe6,479 kt5,531 kt
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe11,219 kt5,360 kt3,153 kt
Daily ore mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe17,800 t10,000 t
Stripping / waste ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1 0.66

Production Costs

CommodityUnits2024202320222021202020192017
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 570 / oz **  
Total cash costs Gold USD 692 / oz  
Total cash costs Gold USD 668 / oz **  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 807 / oz **  
All-in sustaining costs (AISC) Gold USD 1,124 / oz **  
^ Guidance / Forecast.
** Net of By-Product.

Operating Costs

Currency2017
OP mining costs ($/t milled) USD 3.36  
Processing costs ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe

Financials

Units2024202320222021202020192017
Capital expenditures (planned) M USD  ....  Subscribe
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 31.2   69.4  
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 29.9   22.2  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 189.4   95.4  
Operating Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 69.8   30.1  

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Apr 10, 2024
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EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required 2021

Aerial view:

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