Unicorn Mineral Resources Plc says it is increasingly positive about the economic potential of the Klein Aub Copper Mine after glycine leaching tests delivered copper recoveries of up to 70% from slimes and up to 45% from historic tailings, with further optimisation still underway.
The company said the latest laboratory work, carried out on tailings material from the Namibian project, showed materially improved copper recoveries following adjustments to the leaching process, including the addition of an oxidation element, longer test durations and higher operating temperatures.
Unicorn said the recovery curve continued to rise at the end of the tests, indicating the reaction had not yet completed and that further optimisation could yield even higher recoveries.
Earlier test work achieved copper recoveries of about 60% to 70% from slimes and approximately 35% to 45% from tailings, figures that the company has previously described as encouraging for a historic tailing reprocessing project. The latest optimisation programme builds on those results and strengthens confidence in the project’s commercial viability.
The metallurgical test work is being conducted by Draslovka using its proprietary glycine leaching technology. The current phase of testing has focused exclusively on copper extraction, with further work planned to investigate the potential recovery of silver from the tailings.
Unicorn said the results remain preliminary and have been submitted for independent analysis.
The company is progressing the acquisition of a 75% interest in Klein Aub, as announced in November 2025, with completion expected in April 2026.
Unicorn said the improving recovery profile supports its strategy of redeveloping the historic mine as a low-impact tailings retreatment operation.
Chairman Paddy Doherty said the partnership with Draslovka is proving critical in unlocking value from the project.
“We are delighted to be working with Draslovka on these tests. Their expertise in glycine leaching technology, an environmentally friendly approach to extracting value locked up in tailings, is helping to move this project from concept to a commercially viable proposition,” Doherty said.
Klein Aub is a former underground copper mine near Rehoboth in Namibia’s Hardap Region that ceased operations in the late 1980s, leaving behind significant volumes of surface tailings containing residual copper.
At the time, lower copper prices and processing constraints rendered further recovery uneconomic.
Growing global demand for copper, driven by electrification and the energy transition, has renewed interest in historic tailings projects such as Klein Aub.
Glycine leaching, which uses an amino-acid-based reagent instead of conventional acids, is increasingly viewed as a lower-impact processing option for brownfield copper assets, particularly where legacy tailings offer scale without the cost and risk of reopening underground operations.
