Cyclone Metals Limited (ASX: CLE) has obtained initial results from the recent round of metallurgical testwork conducted on samples from its Lady Ethleen copper gold project in north-western Queensland.
The test work involved initial leach tests on all three sample types using acid only to simulate conventional leaching methods and provide reference results to enable comparison of subsequent alkaline leaching technology.
Acid only results for as received sample (P80 ~ 2mm) using ~80 kg per tonne of acid demonstrated copper recoveries of 85% for oxide, 49.6% for transitional and 44.1% for sulphide.
After curing the as received (P80 ~ 2mm) samples in dilute acid (10kg per tonne) and leaching with GlyLeach using resin (for extraction) followed by a hot wash with water, copper recoveries were found to increase to 92.9%for oxide, 65.2%for transitional and 64.9%for sulphide.
Non-Executive Chairman, Terry Donnelly, said these numbers are expected to increase further if the sample is ground prior to processing up to possible recoveries of ~85% for sulphide.
This process allows for very minimal acid usage which is entirely consumed followed by use of the recoverable GlyLeach lixiviant leading to potentially reduced costs and a significantly more environmentally friendly process.
Based on the success of these results, stage 2 of the testwork has been approved and is now underway.
This work will consist of:
- Small column leach tests on as received sample with acid cure, glycine leach stripped with resin and hot water wash to simulate heap leaching;
- Continuous vat leach tests on as received sample with acid cure, glycine leach stripped with resin and hot water wash;
- Reactor leach tests on as received sample with acid cure, glycine leach stripped with resin and hot water wash to simulate a horizontally rotating reactor (similar to a cement mixer truck);
- Additional inclusion of cyanide using the Glycat technology to recover any gold present in the samples.
Following success of stage 2, the company will assess conducting pilot trials envisaging the use of truck/trailer mounted horizontal reactors based on or near site to demonstrate processing practicality at increased scale.
These are very encouraging results and allow the company to move to stage two testing. Together with the newly acquired Nickol River Mining Project and our existing Yalardy Project the company is in an excellent position to further development a portfolio of prospective projects in multiple commodities including gold, copper and rare earths,” Mr Donnelly said.