Cobre Ltd (ASX:CBE) has achieved copper recoveries of up to 77.4% for high-grade samples from the Ngami Copper Project (NCP) in the Kalahari Copper Belt of Botswana, with bottle roll tests carried out on high-grade and low-grade composite samples from the project.
The company improved copper recoveries by more than 20% compared to initial metallurgical tests with the addition of a combination of ferric sulphate and chloride to the leach system, resulting in 77.4% for high-grade samples and 71.9% for low-grade samples.
CBE also found a low chloride concentration allows for the recovery of associated silver mineralisation, which could provide a second metal stream.
High copper recoveries expected
“The metallurgical test results are highly encouraging, demonstrating that the extensive chalcocite dominant mineralisation intersected at NCP can be effectively beneficiated with a leaching solution with high copper recoveries expected,” Cobre CEO Adam Woolridge said.
“The recovery of the associated silver credit is an unexpected bonus.”
The company says these latest metallurgical results provide further evidence for the potential to beneficiate the copper-silver mineralisation at NCP using an in-situ copper recovery process (ISCR).
CBE intends to generate further evidence with a series of pump tests to begin in the current quarter. Cobre says the ISCR method would provide an effective mining method at the bottom of the global cost curve with low environmental impact, should it prove amenable.