Rox Resources (ASX: RXL) and joint venture partner Venus Metals Corporation (ASX: VMC) have confirmed that initial gravity and cyanide leach recovery tests have delivered high gold recoveries from the Grace deposit at the Youanmi gold project in WA.
Youanmi sits within the OYG joint venture area, in which Rox holds a majority 70% stake and Venus holds 30%.
The work at Grace was conducted by Perth-based ALS Metallurgy to test oxide and fresh samples from two earlier reverse circulation drillholes as a sighter program to aid in the design of a more comprehensive testing regime.
Rox managing director Alex Passmore said the results were a positive step forward for the joint venture.
“[We are] pleased with these excellent initial metallurgical test work results, particularly the relatively high gravity recoverable gold from a coarse grind,” he said.
“Gold ores at Youanmi show a variety of metallurgical characteristics however it is becoming evident that granite-hosted, low sulphide mineralisation [such as that found] at Grace are free milling and therefore amenable to conventional carbon-in-leach processing.”
Test samples were collected from coarse rejects weighing approximately 30 kilograms and considered typical examples of mineralisation at Grace.
They were crushed to less than 3.35 millimetres and split using a rotary sample divider to create two 1kg composites, which were further ground down and assayed before being put through a Knelson Concentrator (synonymous with industry-best gravity gold recovery).
Tails and intensive cyanidation residue from the Knelson process were subjected to a 24-hour bottle roll using Perth tap water and the recovered gold in solution was then added to the gravity-recovered component to give total recovered gold for the sample.
Residues were tested by fire assay and a final gold recovery calculated.
Rox said the testwork produced a total gold extraction of up to 99.8% using a combination of gravity and 24-hour cyanide leach bottle rolls.
The gold recovered is believed to be hosted in low-suphide mineralisation within fractured, altered granite over a corridor extending 2.5km to the north of the historic Youanmi mine area.
High gravity recoveries of up to 69% of total gold recovered were achieved through the Knelson concentrator prior to cyanide leaching.
The results indicate that Grace will be amenable to a conventional gravity and cyanide leach processing circuit.