First Quantum’s La Granja copper giant: design and risk notes for project engineers
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
First Quantum Minerals’ updated NI 43-101 for the La Granja copper project in northern Peru outlines 4.8 billion tonnes of measured and indicated resources at 0.48% Cu (23.0 Mt contained), plus 5.2 billion tonnes inferred at 0.40% Cu (20.7 Mt), based on 832 diamond holes totalling 370,000 metres. The company plans pit-side comminution and slurry transport via a 7 km tunnel to a processing and tailings complex on a flatter Pacific coastal plain ~100 km away, using desalinated seawater as primary supply. Engineering focus centres on managing arsenic as discrete, “packageable” mineral phases to maintain saleable concentrate through a conventional flowsheet under Peru’s strict ESIA regime.
Technical Brief
- Pit optimisation used a copper-only cut-off at a long-term price assumption of $4.00/lb.
- Processing and tailings are planned on an arid Pacific coastal plain ~100 km from the open pit.
- Ore will be slurried and pumped through a 7 km tunnel after pit-side comminution, reducing high-altitude plant footprint.
- Primary process water will be desalinated seawater, with contact water capture and reuse to limit freshwater abstraction.
- La Granja lies at 2,000–2,800 m elevation, easing logistics compared with higher Andean copper operations.
- Project capex was previously estimated by the Peruvian government at over $2.4 billion for full development.
- First Quantum acquired 55% from Rio Tinto for $105 million and has already invested $70 million of a $546 million commitment.
- Taca Taca, another First Quantum greenfield copper project, targets 291,000 t/y Cu at 97¢/lb cash cost over its first decade.
Our Take
The use of a $4/lb copper price for pit optimisation at La Granja versus the stated $6.65/lb market price signals that project economics are being framed against a conservative price deck, which should matter for lenders such as IFC that are already engaged with First Quantum at Taca Taca on performance and ESG standards.
A projected life-of-mine cash cost of $1.26/lb at Taca Taca, combined with La Granja’s very large but low-grade resource in northern Peru, suggests First Quantum is building a portfolio of scale copper assets in the South American copper belt that could sit in the lower half of the cost curve if infrastructure and community agreements are secured on schedule.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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