Successful Electrochemical Recovery Of 99.9% Pure Copper Metal From La Plata Sulphide Mineralization

VANCOUVER – Metallic Minerals Corp. reported on its research collaboration with Columbia University under its “Mines of the Future” initiative. The study demonstrates the successful electrochemical recovery of high-purity copper metal directly from sulphide mineralized material at the Company’s La Plata copper-silver-gold-PGE critical minerals project in southwestern Colorado.
Researchers at Columbia University’s Gadikota Research Group have established proof-of-concept for an ambient-temperature electrochemical oxidative leaching process applied directly to whole La Plata chalcopyrite-dominant sulphide material without prior flotation concentration. Chalcopyrite is widely recognized as the most abundant copper sulphide mineral and one of the more refractory primary copper sulphide phases.
In initial laboratory-scale testing, approximately 70% of the copper contained in sulphide from drill samples was selectively solubilized within four hours at ambient temperature without prior flotation, roasting, or pressure oxidation. The dissolved copper was subsequently recovered through controlled electrodeposition, producing 99.9% pure metallic copper as confirmed by X-ray diffraction analysis. Near-complete recovery of copper from solution was achieved during the electrodeposition step.
These results demonstrate, for the first time on La Plata mineralized samples, that direct electrochemical oxidative leaching can effectively dissolve copper from chalcopyrite-dominant sulphide mineralization under mild conditions. This demonstrates early-stage, laboratory-scale proof-of-concept for a potential electrochemical copper recovery pathway, where copper may be produced directly via electrowinning rather than through conventional concentrate production and transport to a smelter.
Importantly, under the leaching conditions employed, silver (Ag), rare earth elements (REEs), platinum group elements (PGEs), and gold (Au) do not report to the copper solution. Instead, these metals partition into an iron-rich solid residue formed during the process. This natural metal partitioning enables high-purity copper recovery in a streamlined two-stage process-leaching followed by electrodeposition-while simultaneously generating a separate iron-REE-PGE enriched residue for subsequent downstream recovery.
The tests were conducted on mineralized drill core material without prior concentration as an initial feasibility step. Based on the sulphide mineralogy and established metallurgical principles, the Company anticipates that pre-concentration of the sulphide fraction through conventional flotation and other upgrading processes could materially enhance copper recoveries in subsequent optimization work. Achieving approximately 70% leach recovery of copper under ambient conditions and short reaction times is notable given the chalcopyrite-dominant sulphide mineralization tested.
The electrochemical system utilizes in situ generation of hydrogen peroxide to promote oxidation of less soluble Cu⁺ species to soluble Cu²⁺, enabling selective dissolution. Following copper electrodeposition, the leaching reagents are regenerated in situ without additional pre-treatment, supporting a closed-loop system design with potential operating and capital efficiency benefits.
Removal of copper from solution represents the first stage of a broader comprehensive mineral valorization strategy being evaluated with Columbia University. The selective partitioning of REEs, PGEs, silver, and gold into an iron-rich residue provides a defined secondary feedstock for subsequent recovery of these critical minerals. Ongoing research is focused on developing selective extraction pathways for REEs, PGEs, and other critical minerals from this iron-rich residue, representing a second phase of technology development and intellectual property advancement. Intellectual property protection strategies are being evaluated covering these process innovations.
Greg Johnson, CEO & Chairman, said, “These results demonstrate that copper can be selectively dissolved from La Plata’s chalcopyrite-dominant sulphide mineralization and recovered directly as 99.9% pure metal in a streamlined two-stage electrochemical process. Importantly, silver, rare earth elements, platinum group metals, and gold remain in an iron-rich residue, creating a natural partitioning of metals that simplifies downstream recovery pathways.
“As we continue to optimize and expand this work, our objective is to evaluate whether this technology can enhance overall metal recoveries while supporting a regenerative, lower-energy processing pathway. If successfully advanced, this approach may enable value-added metal production closer to the source-helping to retain more economic benefits locally, reduce reliance on high-temperature smelting, and support a more circular and responsible model of resource development.”