St George Mining has kicked off a crucial pilot plant study at its massive Araxá niobium and rare earths project in Brazil, marking a key step in developing a processing flowsheet to unlock the value of two sets of critical minerals from the one deposit.
Work has now begun at the Brazilian Centre of Innovation and Technology's national service for industrial training (CIT-SENAI) advanced laboratory facility in Belo Horizonte, using an estimated nine tonnes of saprolititic - or weathered - near-surface sample material. The study, which is expected to run for four to six weeks, aims to build on earlier successful tests that delivered a high-grade niobium concentrate and a separate rare earths-enriched tailings stream.
The pilot plant program is designed to deliver two distinct product streams for further downstream evaluation. The niobium concentrate will undergo further pyro-metallurgical test work to produce ferroniobium, aiming for a target grade of approximately 65 per cent niobium.
Meanwhile, the rare-earth-enriched tailings from the niobium flotation circuit will be put through hydrometallurgical testing to create an intermediate product, such as mixed rare earth carbonate (MREC) or rare earths oxalate.
The company says results from the beneficiation test work are expected in the fourth quarter of this year.
The move comes as Brazil is being actively courted by the US and Europe for its critical minerals supply, adding strategic relevance to new Brazilian niobium and rare earths projects. The global rare earths market remains tight and geopolitically sensitive, with Western nations scrambling to build new supply chains outside China. The metals are poised to meet the growing demand for high-strength rare earths magnets and niobium used in everything from electric vehicles to wind turbines, defence equipment, electronics and medical equipment.
St George Mining executive chairman John Prineas said: "Our initial flotation test work produced niobium concentrate with recoveries and grades that are consistent with niobium mining operations for Araxá-style pyrochlore mineralisation. Significantly the test work also achieved significant upgrading of the rare earths in the niobium flotation tailings. This beneficiation work stream is an important step in our journey to advance the development potential of Araxá to become a globally significant producer of rare earths and niobium."
The pilot plant testwork is aimed at de-risking the metallurgy for what is now considered South America’s biggest and highest-grade hard-rock rare earths resource. The project, positioned in the mining-friendly state of Minas Gerais, hosts a mammoth total combined resource of 111.2 million tonnes grading an impressive 3.57 per cent total rare earth oxides (TREO) and 0.57 per cent niobium pentoxide.
That resource contains an estimated 760,000 tonnes of valuable neodymium-praseodymium (NdPr), oxides and 630,000 tonnes of niobium pentoxide. A hefty 75.2 million tonnes of the inventory sits in the higher-confidence measured and indicated categories.
Importantly, the entire deposit lies within 120 metres of the surface in soft, weathered saprolitic clay, making it potentially amenable to simple, low-cost open-pit mining, much of it directly from surface.
While the current study is underway, St George is already building its own, larger-scale pilot plant at the St George Technological Centre within the Federal Centre for Technological Education of Minas Gerais (CEFET-MG) campus in Araxá.
Construction of the Technological Centre has already started, with completion slated for December and first operations in January 2027. The plant will have a throughput capacity of up to 300 kilograms per hour and will produce both niobium and a range of rare earth products.
To execute its Brazilian strategy, St George has assembled a formidable in-country team stacked with former senior figures from CBMM – the world’s largest niobium producer, whose mine sits right next door to St George's Araxá deposit. The line-up includes former CBMM head of mineral processing, Ricardo Nardi and former production manager Adriano Rios.
With a pilot plant study now spooling up and a bigger, company-owned pilot facility already under construction, St George is steadily chipping away at the myriad tasks required to turn its giant resource into a producing asset. With a who's-who of local niobium talent now on its payroll, the company seems to have placed the right people in the right place to get it all done.
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By Doug Bright
