Metallurgical testwork at Xanadu Mines’ Kharmagtai copper-gold project in Mongolia has highlighted impressive recovery levels of 80 per cent from sulphide feed and a high-grade concentrate with low impurities.
The potentially-saleable concentrate shows grades of up to 25 per cent copper and 25 grams per tonne gold from the porphyry deposits at the company’s South Gobi site in the landlocked East Asian country. The testwork results, which will be included in an upcoming prefeasibility study (PFS), build upon previous testing used for a 2022 scoping study.
Management says the key objectives of the program included ore hardness and comminution attributes, optimal grind sizing, gravity gold recoveries and copper-gold recoveries by froth flotation.
Xanadu completed full locked-cycle testwork (LCT) across representative deposit and master composites. The program defines a conventional flowsheet of crushing, grinding and flotation to produce a concentrate that management believes could attract strong market demand.
It can also use the oxide feed from the top 20m of the deposits to produce gold doré through an upfront gravity circuit, along with leaching of cleaner tails that can be further processed to extract purely the gold content.
The company says it collected 132 samples across five deposit types based on geometallurgical models specifically built for rock type, alteration type, sulphide species and grade. It ensured the selected samples represented a spread across the various modelled categories.
Xanadu Mines executive chairman and managing director Colin Moorhead said: “This concludes a comprehensive metallurgical testwork program which aimed to define the optimal ore processing pathway for the key deposits at Kharmagtai. Results are within our expectations, delivering a high-quality gold-rich copper concentrate that we expect to be in high demand.”
The company notes that its more significant PFS data set provides the basis for product quality, overall recovery levels and process engineering design. The combined process plant is expected to deliver average recoveries of about 81 per cent copper and 80 per cent gold from sulphide feed, which will be made up of gravity gold recoveries of 10 per cent and simple flotation recovery of 81 per cent copper and 63 per cent gold. Carbon-in-leach (CIL) recovery adds a further 7 per cent gold.
Management added that using the LCT method with the addition of sodium cyanide lifted the copper concentrate grade to 26.3 per cent and recovery levels remained the same. It says the PFS is due in the coming weeks and will contain the metallurgical testwork results.
The Kharmagtai project has an existing mineral resource estimate of 3.8 million tonnes of copper and 9.3 million ounces of gold. It is anticipated to initially be a bulk-scale open-pit operation with a 30-year mine life.
The operation has a mining licence across a 40 square-kilometre district and more than 280km of drilling has been completed at the project, with a big portion of the resource sitting in the indicated category.
Xanadu has a joint-venture (JV) at Kharmagtai with Shanghai-Hong Kong stock exchange-listed Chinese giant mining firm Zijin Mining, worth an estimated $US56.8 billion ($AU84 billion). The two firms have an evenly-split JV through Khuiten Metals, which controls 76.5 per cent of the project.
Effectively, it provides Xanadu with a 38.25 per cent interest in the imposing future operation, where the aim is to begin concentrate production in late 2027 or early in 2028.
The company says Kharmagtai comes with the benefits of new discoveries that continue to grow the resource, increasing grade with depth. It also has existing power and water and transport infrastructure in close proximity to the site.
Management adds that South Gobi is known for its deep aquifers with plenty of water, which should enable sufficient resources for its expected initial 26 million tonnes per annum mining and processing operation.
The renowned Rio Tinto-Mongolian Government’s jointly-owned Oyu Tolgoi mine sits within the South Gobi Desert and is considered one of the world’s biggest copper-gold deposits. Xanadu says Kharmagtai’s open-pit potential is similar to Oyu Tolgoi, albeit without the huge underground development.
The company appears to have a sizeable grip on a monster copper-gold deposit. With gold prices on the march, it may only need copper prices to join the party to begin to reap the real benefits of the massive project.
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By Craig Nolan
