Great Boulder Resources (ASX:GBR) has achieved high gold recoveries of up to 98.7% from metallurgical testwork on samples from the Mulga Bill Project in Western Australia.
The testwork, completed by Independent Metallurgical Operations (IMO), was designed to look at gravity and cyanide leach recoveries of gold over various grind sizes. The testwork also considered whether the presence of copper minerals would negatively impact cyanide consumption and gold recovery.
Great Boulder, which has a market capitalisation of $35.67 million, says the results were positive, with high gold recoveries and low levels of cyanide-soluble copper.
As a result, copper levels within Mulga Bill will not unduly affect gold recoveries of cyanide consumption.
Managing Director Andrew Paterson says the results demonstrate that Mulga Bill is amenable to industry standard cyanide leaching and can be processed at any of the existing gold mills in the Meekatharra region. This means that it can be processed through a conventional gold plant or any of the existing gold plants in the region.
“This is a hugely important outcome, as it removes one of the last remaining questions around potential mine development at Side Well,” Paterson says.
“Mulga Bill has the majority of gold ounces known to date, so it will always be the engine room of any mining operation here, and hence we’re extremely pleased and excited with this outcome.”
In the next stage of testwork, IMO will run a series of reagent optimisation tests to examine the effect of varying cyanide concentration levels while keeping the grind size constant.
Further testing will look at blending the MET-1 and MET-2 samples to achieve a cyanide-soluble copper concentration of 170 parts per million, which is the highest level at which copper has had negligible effect on cyanide consumption and leach times in this round of results.
If this is achieved, subsequent tests will look to further optimise blend characteristics by testing higher levels of cyanide-soluble copper to find the maximum permissible cyanide-soluble level.
The Mulga Bill Project sits within the Side Well Gold Project which has a defined mineral resource of 7.45 million tonnes @ 2.8g/t gold for 668,000 ounces of gold.
Great Boulder Resources is a mineral explorer focused on its portfolio of gold and base metals projects in Western Australia.
Write to Aaliyah Rogan at Mining.com.au
Images: Great Boulder Resources
