Mining Intelligence and News
Argentina

Josemaria Project

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Overview

Mine TypeOpen Pit
StagePermitting
Commodities
  • Copper
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
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Mine Life... Lock
SnapshotJosemaria is a large-scale copper-gold-silver project.

A study to increase plant throughput was finalized in the fourth quarter of 2023. Additional studies including concentrate transportation, infrastructure review, mine optimization and equipment selection, execution plan update, and commercial strategies will be completed in 2024.

The Josemaria Project team is working with the national and provincial authorities to progress the project through the next stages of development, including securing additional sectorial permits.

Owners

SourceSource
CompanyInterestOwnership
Lundin Mining Corp. 100 % Indirect
Desarrollo de Prospectos Mineros S.A. (operator) 100 % Direct
Desarrollo de Prospectos Mineros S.A. is a wholly-owned indirect subsidiary of Lundin Mining that owns the Josemaria Project.

In 2022, Lundin Mining acquired the Josemaria Project located in Argentina.

Contractors

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Deposit type

  • Porphyry

Summary:

The Josemaria project area is underlain most extensively by Permo-Triassic rocks assigned to the Choiyoi Group, which forms the Andean basement in the region. They include volcaniclastic and ignimbritic rhyolites as well as broadly equivalent granites. Triassic intrusive complexes of tonalite, diorite and granodioritic composition intrude the rhyolites and granite. Swarms of andesite dykes, which are typical of the Permo-Triassic in this region, cut the older Permo- Triassic units.

Porphyry intrusive rocks and associated porphyry and epithermal mineralized systems are largely hosted within basement rocks. Late Oligocene systems form a north-south trend extending from Josemaria to the Sillimanita and Cerro Blanco Cu-Au porphyry prospects formed around similar dacitic intrusions. Middle Miocene systems such as the Filo del Sol porphyry-epithermal Cu-Au-Ag deposit and the Los Helados porphyry Cu-Au deposit occur several kilometres westward.

The Josemaria porphyry copper-gold deposit is centred on a Late Oligocene dacitic porphyry intrusive complex emplaced into Permo-Triassic rhyolite and tonalite. Porphyry ascent and localization appears to have been guided by a pre-existing north-south structural zone.

The Cu–Au mineralization at Josemaria is hosted within a porphyry system that includes two main types of hypogene mineralization. These two types occur in proximity to one another due to a high degree of telescoping of high-sulphidation alteration and mineralization over deeper mineralization related to potassic alteration. Late supergene enrichment within the northern part of the deposit has upgraded copper values over part of the system. Deposit dimensions, defined by the current resource, are ~1000 m east-west, ~1500 m north-south, and 600 to 700 m vertically.

The first and most widespread type of hypogene Cu and Au mineralization is associated with the upper parts of the potassic alteration zone (Min zone PyCpy). Disseminated and vein-style chalcopyrite mineralization is associated with an A-type quartz-magnetite veinlet stockwork in the area above and around the porphyry intrusions. Minor bornite is present, but in an approximate ratio of 30:1 (chalcopyrite:bornite) within the potassic zone.

Sericite-chlorite-clay alteration overprints potassic but was not grade-destructive and some of the best Cu grades are found in the SCC domain. Where overprinted, which is through much of the deposit, the sulphide assemblage has been variably reconstituted to pyrite-chalcopyrite with pyrite:chalcopyrite ratios of approximately 3-10:1. Copper and gold values are in the range of ~0.35% Cu and 0.2 g/t Au.

This Cu-Au mineralization is overlapped by a molybdenite-bearing annulus best developed on the northern and eastern sides, with grades averaging > 50 ppm Mo. It is related to molybdenitebearing B-veins surrounding the central part of the system.

The second type of hypogene sulphide mineralization is located along the western and central parts of the system, associated with the advanced argillic domain and the underlying sericitic alteration (Min zone PyCc(H)). This high-sulphidation assemblage includes disseminated grains of pyrite rimmed by hypogene chalcocite, bornite and/or covellite with trace amounts of tennantite and enargite. Arsenic values are relatively low, in the range of ~10–100 ppm. Pyrite:copper-bearing sulphide ratios are roughly 10:1.

In the central part of the system, where the highest degrees of alteration telescoping are mapped, the high-sulphidation alteration extends downward over the potassic- and SCC-related chalcopyrite mineralization. In this area, the early potassic-related sulphide mineralization is reconstituted and upgraded by the high-sulphidation sulphide assemblage, reflected in higher gold and hypogene copper grades in the central part of the system. In places values of ~0.6% Cu and ~0.7 g/t Au are attained in the south-central, highest grade part of the system.

Supergene copper enrichment (PyCc(S)) is focused along the NNE structural zone through the northern part of the deposit. The Late Oligocene erosional event removed the upper parts of the mineralized system, but erosion took pace at a rapid rate that did not allow for development of an extensive leached cap or supergene enrichment at that time. Only more recently, likely during most recent glacially-aided erosion into the system, has a leached cap been developed over the system (Ox and Mix) with an underlying supergene enrichment zone. The leached zone ranges from 10–20 m in thickness over the relatively impermeable felsic volcanic rocks in the west to a maximum of 230 m within the Josemaria NNE structural corridor and the tonalite farther east where it was facilitated by damage zones along faults and increased permeability through groundwater removal of sulphate veins. The underlying supergene enrichment domain attains grades in the range of 0.8-1.5% Cu.

Appreciable oxide Cu (malachite and neotocite) mineralization is restricted to a small zone of fractures within the leached cap (Ox) in the northern part of the deposit. This is interpreted to be the result of leaching of the pyrite-poor potassic domain. Also, a significant Au-rich portion of the leached cap occurs along the centre of the deposit, between section lines 4100N and 4600N, with values averaging 0.35 g/t Au within the oxide zone. This area corresponds to the central, and perhaps deepest, parts of the advanced argillic alteration zone within the system.

Based on geological features and location, the Josemaria deposit is classified as a Cu–Au porphyry system.

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

CommodityProductUnitsAvg. AnnualLOM
Copper Concentrate kt 9,600
Copper Payable metal M lbs 2895,503
Gold Payable metal koz 2244,257
Silver Payable metal koz 1,04819,903
Copper Equivalent Payable metal M lbs 7,751

Operational metrics

Metrics
Daily milling capacity  ....  Subscribe
Annual milling capacity  ....  Subscribe
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Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Total tonnes mined, LOM  ....  Subscribe
Tonnes milled, LOM  ....  Subscribe
* According to 2020 study.

Production Costs

CommodityUnitsAverage
Cash costs Copper Equivalent USD  ....  Subscribe
All-in costs Copper Equivalent USD  ....  Subscribe
Assumed price Copper USD  ....  Subscribe
Assumed price Silver USD  ....  Subscribe
Assumed price Gold USD  ....  Subscribe
* According to 2020 study / presentation.

Operating Costs

Currency2020
OP mining costs ($/t mined) USD 1.2 *  
OP mining costs ($/t milled) USD  ....  Subscribe
Crushing costs ($/t milled) USD  ....  Subscribe
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2020 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Working capital $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 2,974
Freight costs $M USD 1,615
Refining and transportation $M USD  ......  Subscribe
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
Total Taxes $M USD  ......  Subscribe
Royalty payments $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Required Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Mar 4, 2024
....................... Subscription required ....................... Subscription required Subscription required Nov 5, 2020
....................... Subscription required ....................... Subscription required Subscription required Nov 5, 2020
....................... Subscription required ....................... Subscription required Subscription required Nov 5, 2020
....................... Subscription required ....................... Subscription required Subscription required Mar 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 4, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 4, 2024

Total WorkforceYear
...... Subscription required 2020

Aerial view:

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