Coda Minerals (ASX:COD) has reported the successful concentration of cobalt from material left over from whole-ore chloride leaching.
The program involved a series of flotation tests designed to simulate the addition of a flotation circuit after the whole-ore chloride leach step, but before the residue is disposed of in the tailings storage facility.
Recent test work on representative composites from the Emmie Bluff copper-cobalt deposit has demonstrated average cobalt extraction of 39.7%, with most of the cobalt in the ore reporting to the leach residue.
Emmie Bluff forms part of Coda’s 100%-owned Elizabeth Creek Copper-Silver Project in South Australia.
Coda notes that recovering additional cobalt from this residue could substantially increase overall cobalt recovery.
Test JR012, representing the anticipated chloride leach residue, achieved 83% cobalt recovery into a concentrate grading 1.48% cobalt (Co), at a 4% mass pull from a head grade of 717 parts per million Co. The recovery indicates the amount of metal extracted from the residue into the concentrate, while mass pull indicates the total mass of the concentrate produced following flotation.
To date, the project’s economics have assumed zero cobalt revenue, but the new work indicates potential recovery upside from the mineral resource at Emmie Bluff, which contains around 23,000 tonnes of Co.
Coda is undertaking further leaching tests, with subsequent testing to assess a wider range of samples and the performance of recycled material in the process.
CEO Chris Stevens says that the test work has indicated potential upside in cobalt for Elizabeth Creek that is not currently included in the company’s leach-case economics.
“In the latest laboratory test, we collected 83% of the cobalt left after leaching into just 4% of the residue mass,” Stevens says.
“That gives us a much smaller amount of material to treat and a clear focus for the next stage of work.
“The task now is to extract the cobalt from that concentrate and demonstrate that it makes economic sense. Our preferred option is to return it to the proposed leach circuit, subject to test results.”
Impacts on Elizabeth Creek PFS
As noted, the Emmie Bluff mineral resource holds around 23,000 tonnes of contained Co, with an additional 9,300 tonnes across the Windabout and MG14 mineral resources at Elizabeth Creek.
While early Scoping Studies for Elizabeth Creek included cobalt, the simplified whole-ore chloride leach flowsheet from August 2025 does not.
The flotation results demonstrate a potential way to recover cobalt from the residue for further treatment, rather than sending it to tailings.
Coda Minerals is now assessing how much cobalt can be extracted, which methods to use, and at what cost. Its preferred approach is to return the concentrate to the proposed chloride leach circuit.
The company notes that if re-leaching is effective, there is also an opportunity to increase copper and silver recovery, as both metals were concentrated above their residue head grades.
If re-leaching is not a viable pathway, the company could consider a dedicated circuit for treating carrollite, the main cobalt-bearing mineral.
Coda Minerals is now conducting tests to determine whether cobalt in carrollite can be extracted through a second chloride leach. Ongoing work includes the regrinding of leached residue followed by a 24-hour re-leach under base-case conditions.
Further testing will assess the economic viability of cobalt recovery from the concentrate. Coda Minerals will continue to provide updates to the market as the work progresses.
Alongside this work, the company is progressing its Prefeasibility Study, with metallurgical modelling, engineering studies, groundwater drilling, and environmental studies underway.
Coda Minerals is focused on the discovery and development of minerals aligned with the global energy transition through electrification and renewable energy.
Write to Amy Rotman at Mining.com.au
Main image: Coda Minerals
