Significant metallurgical test work has been conducted on the Chaarat ore since 2005 by both Mintek in South Africa and Resource Development Inc (RDI) in the USA. The Chaarat ore is what is commonly referred to as refractory ore and the recovery of gold requires pre-treatment of the ore to oxidize the gold containing minerals and ease the leaching out of the gold. A comprehensive suite of flotation tests was conducted culminating in a relatively large sample.
The company has further looked into different technologies of oxidation and gold recovery in order to maximise the extractable value of the concentrate. Whilst the work is still ongoing the company is confident, based on results from the work, that 95% of the gold and silver can be recovered by conventional cyanidation followed by CIL extraction.
Whilst further work is required it seems that the company faces two principal operating options;
- Produce and sell low mass pull concentrate. It was shown repeatedly that a flotation concentrate with about 13% mass pull can be produced into which approximately 87% of the gold and over 90% of the silver and antimony are reporting. This type of concentrate is fairly common in Asia and a number of smelters in both the CIS and China are accustomed to treating such concentrate.
- Produce high mass pull concentrate (which collects over 90% of the gold but is less practical to transport) and treat it by Pressure oxidation followed by CIL.
The decision on which metallurgical process to select will be based on careful economic risk assessment taking into account all relevant facets of the process besides its cost/recovery parameters, such as the environmental and transport risk weighted cost and impact.