Xanadu’s Mongolian copper-gold venture showing a heap of potential
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Special Report: Tests from Xanadu Mines’ Kharmagtai copper-gold project in Mongolia has emerged with news of high gold recoveries.
Xanadu (ASX:XAM) announced this week that it had completed preliminary metallurgical testwork on the diamond drill core from the Golden Eagle deposit at Kharmagtai.
This is where shallow gold mineralisation is hosted in an oxide cap above a deeper and significantly large copper-gold porphyry.
The gravity and leach testwork conducted showed excellent recoveries of up to 92.56 per cent and has raised the prospect of a heap leach gold operation at Kharmagtai as a low-cost and low risk means of moving the project into production.
“These early stage gravity and bottle roll test results on composite samples from Golden Eagle are outstanding,” Xanadu managing director Andrew Stewart said.
“Achieved at a moderate grind size, they indicate high gold recoveries. Standard crushing, grinding and leaching processes are all that will be required to extract all of the economic gold grades from the oxide cap mineralisation.”
Heap leaching involves stacking the mined ore onto a pad – the heap – and irrigating it with chemicals such as cyanide to promote separation of the valuable minerals from the waste rock.
Several major copper and copper-gold deposits around the world that feature oxide gold caps including Sepon in Laos and Tujuh Bukit in Indonesia have started production as heap leach operations.
They are considered low capital cost, low operating cost and low technical risk.
Xanadu has estimated an exploration target for Golden Eagle of 66 million tonnes to 103 million tonnes at 0.3-0.6 grams of gold per tonne for 1-1.3 million ounces of gold.
The exploration target confirms the presence of a substantial oxide gold system with a strike length of about 500m and up to 375m in width at surface, which is mineralised to a depth of at least 200m and remains open.
The company has identified another seven zones of significant shallow oxide gold mineralisation at Kharmagtai and has set exploration targets for each.
“While further drilling is required across the orebody as the project advances, previous intersections of significant widths of shallow oxide mineralisation in our bedrock drilling highlight the potential and shows we have literally scratched the surface at Golden Eagle,” Mr Stewart said.
“Further, it represents an opportunity for a low-cost, high value gold leach operation that could be run early in the life of Kharmagtai, injecting significant cash into the project to offset the cost of developing a large-scale copper-gold mine.”
The indicated and inferred mineral resource at Kharmagtai currently stands at 1.9 million pounds of copper and 4.3 million ounces of gold and is spread across three porphyry deposits: Stockwork Hill, White Hill and Copper Hill.
Based on the recent turn of events, Xanadu will now deliver a scoping study on a larger development at Kharmagtai at the end of March, rather than the starter pit project that was previously envisaged.