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METC was appointed lead engineering, procurement, and project management consultant for the BFS.
METC Engineering: solving the metallurgical puzzle at Omitiomire
In Namibia’s Kalahari Copperbelt lies the Omitiomire copper deposit — a long-studied but technically challenging project containing both oxide and sulphide mineralisation. The fundamental hurdle has always been metallurgical: the ore requires two different recovery routes, each with traditionally narrow economic margins. METC was appointed lead engineering, procurement, and project management consultant for the Bankable Feasibility Study (BFS). In this role, METC Engineering played a pivotal role in the development of the process innovation that finally provided a technically robust and economically viable solution. Unlocking a path forward
Among the key innovations is the adoption of a dynamic heap- leach pad, rather than a conservative static design, providing significantly greater operational flexibility. The process route underpins forecast production of 23–32 ktpa of LME Grade A copper cathode over a 15-year mine life, with lower reagent intensity translating directly into reduced operating cost and environmental impact. John Edwards, METC Chief Metallurgist, notes: “At Omitiomire, we weren’t simply adjusting an existing flowsheet. We revisited the chemistry from first principles. Operating at higher copper concentrations allowed us to control acid behaviour and design a process that is both practical and economically sound.” Nick Tatalias, METC Managing Director, adds: “This project reflects METC’s core philosophy: solve complexity through focused engineering and disciplined test work. We pushed the boundaries where needed but avoided unnecessary complication. The result is a flowsheet that unlocks value for Omico and Namibia.” Beyond the Chemistry As EPCM lead, METC integrated metallurgical findings directly into engineering design, ensuring scale-up fidelity and reducing technical risk. The Omitiomire project stands as a clear example of METC’s ability to advance hydrometallurgical thinking — applying established technologies in new ways to solve long-standing challenges. More than a successful design exercise, it demonstrates METC’s enduring commitment to innovation, value creation and engineered solutions that make difficult projects possible. n
Chloride heap leaching — pioneered globally by MJO in Chile — offered a promising processing alternative to sulphuric acid heap leaching. For Omitiomire, the test work was carried out by Mintek using conventional chloride leach conditions. Early test work confirmed that chloride leaching effectively breaks down sulphide minerals, but slow kinetics and extremely high sulphuric acid consumption threatened economic viability. However, column tests revealed something important: although acid consumption was intense in the first metre of the heap, copper continued to leach effectively in deeper layers. Recognising this as an opportunity, the Omico/Mintek/ METC team proposed operating the heap at elevated copper tenors, shifting the solution chemistry from cupric to cuprous conditions. This approach reduced the acid consumption without compromising on leach kinetics. Follow-up test work confirmed this breakthrough. Acid consumption dropped from roughly 44 kg/t to just 9 kg/t. Leach cycle times shortened from about 300 days to roughly 120 days. Total copper recovery remained strong at ~73.5%. This advance — achieved through multiple test-work phases and detailed modelling — became the foundation of the BFS flowsheet. Engineering innovation with impact This new chemistry introduced several engineering challenges to the process plant design. Drawing on its extensive experience and technical expertise, METC resolved these issues and delivered a BFS flowsheet that optimises the project’s economics.
DECEMBER 2025 - JANUARY 2026 | www.modernminingmagazine.co.za MODERN MINING 23
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