The historic Youanmi Gold Project has produced approximately 670,000 ounces of gold over its lifetime. One of the primary reasons Rox became interested in Youanmi was the potential to apply new technology in the mining industry to progress towards a return to production at a mine and resource that has been idle since 1997.
Our initial scoping level Youanmi Deeps metallurgical test work shows that that using a sulphide float and Pressure Oxidation (POX) process to remove in situ gold from Youanmi sulphide ore, will give us an outstanding recovery of approximately 96 per cent in these ore types.
The options for the treatment of sulphide ores and concentrates include traditional oxidation roasting, Albion Process, POX, and bacterial oxidation (Bi-Ox).
All of these processes – and others – come with pros and cons.
Roasting is generally very capital intensive and applicable to high tonnage projects with long mine life.
Bi-Ox is something that has been around for approximately 30 years but has had some high-profile failures and requires the operators to keep “bugs” alive by making sure their living conditions are optimal at all times.
Under the POX process, ore is mined and crushed to create a fine material, before being mixed with water to create a slurry. The slurry is pumped into a pressure vessel where oxygen is added, and the entire mixture is kept under pressure to aid the oxidisation process. It usually takes approximately 60 minutes to complete the oxidizing process in the autoclave.
Upon leaving the high pressure and temperature atmosphere of the pressure vessel the slurry must be returned to atmospheric conditions. This is accomplished through one or two letdown/flash stages. Once the slurry is at atmospheric conditions it is washed and separated at which point the gold, copper or other minerals can be recovered from the liquid fraction.
The major benefits of POX include the ability to quickly separate gold, copper, and other minerals from sulphide ores, achieve higher recoveries, and reduce environmental impacts.
Rox is keeping an open mind on all of these processes, and others including the Albion Process, and Ox-Tec processes, and will investigate the potential of them all to be applied to the deep ore at Youanmi. Rox will keep the market informed if any decisions are made ahead of the release of a feasibility study for Youanmi, expected in the second half of 2022.