PERTH (miningweekly.com) – Minerals explorer Gunson Resources on Tuesday announced that it would launch a prefeasibility study (PFS) at its MG14 and Windabout copper/cobalt/silver deposits, in South Australia, following the completion of a scoping study.

The ASX-listed junior conducted a series of metallurgical tests to confirm the viability of using a sodium cyanide leaching process to extract copper from the deposits, and to recycle the majority of the sodium cyanide.

The tests resulted in copper recoveries of between 80% and 85%, with a potential upside of more than 90% based on the cyanide-soluble copper remaining in the leach residue, as well as a sodium cyanide regeneration in excess of 80%.

Gunson told shareholders that although still subject to the completion of further studies, the proof of concept results were critically important as they suggested that copper could be economically leached from the MG14 and Windabout deposits.

The company’s farm-in partner Torrens Mining would now conduct further metallurgical testwork, which would lead to a PFS to allow process design to be completed, and the capital and operating costs to be estimated.

The PFS would also include work on refining the leaching process to maximise copper recovery, and to optimise the cyanide recovery system and to examine the flotation of the cobalt and silver components.

“Although it is still early days, we are very encouraged by the results of the test programme, which has demonstrated copper recoveries and cyanide generation levels consistent with Torren’s pre-test objectives,” said Gunson MD Bill Bloking.

MG14 has a Joint Ore Reserves Committee-compliant indicated resource of 1.62-million tonnes averaging 1.4% copper, 397 parts per million (ppm) cobalt and 14 g/t silver. The larger Windabout deposit has a resource of 18.7-million tonnes averaging 1% copper, 500 ppm cobalt and 10 g/t silver.