Arizona Sonoran Copper Company says it has engaged Ausenco as lead engineer to deliver an integrated prefeasibility study (PFS) at the Cactus and Parks/Salyer project, in Arizona, USA, by early 2024.

The project, on private land, is a brownfields site with in-place infrastructure and is accessible via highway.

Additionally, the company is pleased to announce the appointment of Victor Moraila as Chief Engineer, joining as the company transitions into a US-based copper developer.

Ausenco will initially review the Cactus draft PFS and incorporate into the new re-scoped PFS, which includes Parks/Salyer. The study will explore a simple heap leach operation, targeting a potential of 50,000 tons (45,359 t) per annum of LME Grade A Copper Cathode from an on-site solvent extraction/electrowinning (SX/EW) plant.

Mineralised material will be sourced from four deposits initially, including Stockpile, Cactus East, Parks/Salyer and Cactus West.

Pending a successful metallurgical program with Rio Tinto’s Nuton Technologies, and a subsequent commercial agreement, the company and Ausenco will layer in the primary sulphides as a fifth source of mineralised material for the SX-EW plant.

Back in July, Arizona Sonoran announced it had entered into a one-year exclusivity period with Nuton™, a Rio Tinto Venture that, at its core, is a portfolio of proprietary copper leach related technologies and capability. The sulphide potential is not included in the 2021 Cactus preliminary economic assessment, which contemplated a simple heap leach and SX-EW operation over an 18-year mine life, producing an average of 28,000 t/y of LME Grade A copper cathode.

In addition to its own technical staff, Ausenco will lead a technical consultant team comprised of Samuel Engineering, AGP Mining Consultants, Stantec, MineFill Services, Clear Creek Associates and Call & Nicholas Inc.

As part of the PFS work for the project, the company and Ausenco have agreed to complete trade-off and optimisation studies and detailed mine production scenario analysis, in conjunction with AGP Mining, around the following areas:

• Mineralised material sources from an open-pit expansion (Cactus West), underground development (Cactus East and Parks/Salyer), and the existing stockpile;
• Ore handling, storage, and agglomeration;
• Leach pad design and operation;
• Acid storage, consumption and handling;
• Solvent extraction and electro-winning;
• Existing and new infrastructure (as required);
• Preliminary design of access roads in coordination with mine access roads;
• Preliminary design and location of mine support facilities; and
• Mine and geotechnical design.

A PFS detailing the oxide and enriched mineralised material is projected to take approximately 10 months to complete, with results currently expected in the December quarter of 2023. Based on the results of current metallurgical testing with Nuton, layering in the primary sulphide material into the mine plan would extend delivery into early 2024.

George Ogilvie, ASCU President and CEO, said: “As Arizona Sonoran Copper Company emerges as a mid-tier copper developer, we are thrilled to welcome the depth of experiences of both Victor and Ausenco; each rooted in quality and value-driven projects. Looking forward, Arizona Sonoran Copper Company is bolstering the technical services team, necessary team to deliver domestically produced copper into the US copper supply chain, from the third largest independent copper deposit in the US.”