Mining
PSJ Cobre Mendocino has signed a preliminary agreement with Finland's Metso Corporation to acquire the ore processing plant for its future copper mine in Uspallata, in the Las Heras department of Argentina's Mendoza province. The agreement was signed in October in Mendoza.
According to the company, the plant is one of the central components of the operation, and settling it allows PSJ to move ahead with the equipment needed for construction. The company is currently working on the technical definitions required to formalize the definitive contract with Metso.
The agreement covers the full supply of the plant, with equipment for the different stages of ore treatment, including flotation and tailings filtration systems. With that configuration, the project will be able to process up to 42,000 tonnes per day (t/d) of ore, 50% more than the 28,000 t/d originally planned.
According to PSJ, the increase is made possible by the greater water-use efficiency of the filter technology, and is achieved with the same already-approved requirement of 141 liters per second, with no changes to the general layout of the facilities or to the area that was evaluated.
"Bringing Metso on board as a strategic supplier is a significant step forward for PSJ. It strengthens the Project's technical development by integrating internationally recognized technology, with a focus on operational efficiency, optimized water use and compliance with the highest standards in the mining industry," said Fabián Gregorio, president and spokesperson of PSJ Cobre Mendocino.
Tailings Filtration Targets Water Recovery
The company highlighted the addition of tailings filtration, a technology that, it said, will significantly reduce the moisture of the resulting material and recover a larger share of the water used during processing so it can be returned to the production circuit. PSJ presents the change as an evolution of its technical design within the water management scheme planned for the operation.
The system will produce filtered tailings with a higher solids content, which makes them easier to compact, handle and dispose of. The design of the tailings storage facility (TSF) was carried out by Knight Piésold, an international consultancy specializing in tailings storage engineering, geotechnical stability, operational monitoring and mine closure.
According to company data, Metso is present in about 50 countries and has around 18,000 professionals, with experience in crushing, grinding, flotation and filtration, and a track record in copper and other mineral projects.
Who Signed
PSJ Cobre Mendocino was represented by Fabián Gregorio, president and spokesperson; Marcelo Avecilla, CEO; and Enrique Gatti and Pavel Ermolaeff, investors in the project. Metso was represented by:
- Fernando Samanez, vice president of Minerals Sales for South America.
- Hannele Vuorimies, vice president of Global Solutions Sales.
- Einari Ojala, director of Plant Solutions.
- Felipe Viguera, director of EPCM Business Development for Minerals.
- Gabriel Peroni, senior business development manager.
- Tatu Vierma, senior chief engineer for plant mechanics and structures.
The signing came days after a change in the company's leadership. On Oct. 20, PSJ announced the appointment of Avecilla as CEO, replacing Gregorio, who remains president and spokesperson, in charge of leading the company and its institutional relations.
Avecilla is from Mendoza, has more than 20 years in the mining industry and has held executive positions at Mineral Resources, Fortescue Metals Group and BHP, including general manager of Mt Marion, in Australia.
From Environmental Approval and the RIGI to Feasibility
The project, backed by Switzerland's Zonda Metals and Argentina's Alberdi Energy, obtained legislative ratification of its Environmental Impact Statement (DIA, for its Spanish acronym) in December 2025, a requirement under Mendoza's Law 7,722 on metal mining, and with it began its feasibility stage. At the environmental approval stage, the published parameters called for an investment of $559 million and average output of 40,000 tonnes per year of contained copper.
In May 2026, the national government approved its admission to Argentina's Large Investment Incentive Regime (RIGI), the first for a project in Mendoza. At the time, Gregorio, then CEO, said the company expected to begin production in the second half of 2028.
Based on the feasibility data, PSJ projects output of 75,000 tonnes per year of contained copper in its first four years, plus gold and silver, with an investment of close to $800 million and a life of mine (LOM) of 16 years.
For the company, Metso's involvement adds technical knowledge and experience to what PSJ describes as the first copper project that will enter production in Argentina, which has not produced copper since the Bajo de la Alumbrera mine closed in 2018.