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Spain

Cobre Las Cruces (Underground) Project

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Overview

Mine TypeUnderground
StagePermitting
Commodities
  • Copper
  • Zinc
  • Lead
  • Silver
Mining Method
  • Longhole open stoping
  • Drift & Fill
  • Longitudinal open stoping
  • Transverse open stoping
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Mine Life... Lock
SnapshotFrom 2009 to 2021 Cobre Las Cruces has been producing cathodes from open pit mined secondary copper ore by means of hydrometallurgical processing. Tailings reprocessing commenced in January 2021 and was completed in June 2023 after which the current plant was placed onto care and maintenance. As of September 2023, there remains 5 million tonnes of Indicated Primary Polymetallic sulphide (PPS) Mineral Resource on stockpile.

The proposed Project comprises a new dual drift access underground mine and will process complex polymetallic primary sulphides. High recovery processing will produce final commercial products of copper cathodes, zinc ingots, silver cement and metallic lead briquettes. The existing plant will be supplemented with a new bulk flotation, zinc solvent extraction, zinc electrowinning and a chloride leaching facility, and with a lead and silver recovery plant.

Environmental permits were granted in June 2021 with the water concession granted in March 2023.
Related AssetCobre Las Cruces

Owners

SourceSource
CompanyInterestOwnership
First Quantum Minerals Ltd. 100 % Indirect
Cobre Las Cruces, S.A. (operator) 100 % Direct
In April 2013 First Quantum Minerals acquired 100% ownership of Cobre Las Cruces. The site operating entity is Cobre Las Cruces S.A.U. (CLC) of which FQM holds a 100% interest.

Contractors

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Deposit type

  • VMS
  • Breccia pipe / Stockwork

Summary:

The Cobre Las Cruces (CLC) deposit is overlain by 150 to 200 m of Cenozoic Guadalquivir Basin sediments which, towards the base, hosts a confined porous aquifer (1 to 3 m thick) known as the Niebla-Posadas Aquifer. The aquifer has a ph of ~ 8.0, low salinity and a temperature of 18-31 °C. The host Paleozoic sequence underlies these basin sediments and has an east-west strike, dipping between 20° to 45° to the north. The Paleozoic rocks also contain pressurised water which is more saline and with temperatures between 22 to 43 °C. No methane has been intersected in either of the aquifers.

Deposit Types
The CLC deposit is a Volcanogenic Massive Sulphide (VMS) deposit which has resulted from precipitation of metals from hydrothermal fluids in a volcanically active sub-marine area. The metals precipitate as sulphides inter-layered with the volcanic sediments. Consequently, CLC’s mineralization is hosted by black shales, sedimentary and felsic volcaniclastic rocks.

The deposit is characterized by a tabular dipping massive sulphide body underlain by a stockwork vein system. The deposit has been folded and faulted, resulting in dislocated mineralised volumes. Hydrothermal alteration is typically chloritic/quartz sericitic and is restricted to the stockwork zones. CLC deposit shows zonation where copper rich volumes are flanked by zinc and lead mineralization. Lead, zinc and silver tend to concentrate in unevenly distributed polymetallic zones. Minor gold is noted in both polymetallic and copper rich areas. Pyrite is dispersed throughout.

At CLC, post-deposition tectonism uplifted the deposit, exposing it to erosion and weathering with partial oxidation of some of the primary sulphides. An uppermost copper-leached gossan resulted with some immobile gold and silver and overlies the cementation zone of secondary sulphide mineralization.

Primary Polymetallic Sulphide (PPS) Mineralization
PPS mineralization comprises two mineralization domains, primary massive sulphides and semi-massive primary sulphides or stockwork.

The primary massive sulphide occurs as a single 30 to 130 m thick lens with around 1,000 m of strike and a 500 m down dip length. Primary mineralization underlies secondary mineralization and is open at depth and to the northeast. Mineralization thickens to the west but is truncated by a north-south striking fault. The PPS massive sulphide mineralisation is underlain by a zone of mineralised stockworks.

The primary massive sulphides have an upper Zn-rich zone and a lower Cu-rich zone interbedded with barren massive pyrite. Sulphides are dominated by pyrite with chalcopyrite, sphalerite, and galena. The polymetallic zones contain centimetre-thick bands of alternating pyrite + chalcopyrite and sphalerite + chalcopyrite + galena. Deformation is responsible for the formation of alternating layers of sphalerite-chalcopyrite-galena and pyrite. The sulphides other than pyrite show widespread recrystallization to a granoblastic assemblage hosting abundant minute subhedral pyrite.

The massive sulphides show conspicuous layering with few clear sedimentary features. Features include banding and graded bedding, especially in the interbedded shale and chert. However, the widespread late recrystallization has masked most primary features.

While the uppermost shale-hosted massive sulphides are likely to be exhalative, the lowermost orebody formed mainly by replacement. Evidence of replacement includes the presence of relicts of variably altered dacite within the massive sulphides and a gradual contact with the underlying stockwork mineralised zone. No oxidation has been observed in the hanging wall of the massive sulphides, thus indicating that seafloor oxidation processes were minimal and that the massive sulphides were originally isolated from an oxidising open ocean.

The PPS massive sulphide mineralization is underlain by a mineralised stockwork and related hydrothermal zone which extends some 200 m beneath the massive sulphides and tends to be copper rich with localized zinc. The stockwork is hosted in hyaloclastic dacite and shale having chlorite ± quartz alteration. The stockwork veins are between 0.5 to 2 cm thick and are folded or sub-parallel to the dominant foliation.

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

Primary polymetallic sulphides processing treats copper, zinc and lead (bearing silver) primary sulphides to produce the four metals as commercial products, specifically copper cathodes, zinc ingots, lead metal briquettes and silver metal cement.

The proposed PMR Project comprises a new dual drift access underground mine producing up to 2.0Mtpa, feeding a polymetallic refinery with a design throughput of up to 2.2 Mtpa. Additional ore feed of 0.2Mtpa will be sourced from existing surface stockpiles to meet plant capacity:
- Ore mined LOM: 36,546 kt
- Ore reclaimed from stockpile LOM: 5,121.9 kt
CommodityProductUnitsAvg. AnnualLOM
Copper Cathode M lbs 44889
Copper Payable metal M lbs 889
Zinc Payable metal M lbs 871,742
Lead Payable metal M lbs 38755
Silver Payable metal koz 93217,057
Copper Equivalent Payable metal kt 41

Operational metrics

Metrics
Annual ore mining rate  ....  Subscribe
Annual processing capacity  ....  Subscribe
Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2023 study.

Production Costs

CommodityUnitsAverage
Assumed price Lead USD  ....  Subscribe
Assumed price Zinc USD  ....  Subscribe
Assumed price Copper USD  ....  Subscribe
Assumed price Silver USD  ....  Subscribe
* According to 2023 study / presentation.

Operating Costs

Currency2023
UG mining costs ($/t mined) USD  ....  Subscribe
UG mining costs ($/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 2023 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
UG OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 2,391
G&A costs $M USD 321.6
Total OpEx $M USD  ......  Subscribe
Total Taxes $M USD  ......  Subscribe
Royalty payments $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 10% $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe

Required Heavy Mobile Equipment

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Personnel

Mine Management

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Aerial view:

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