St George Mining Ltd (ASX:SGQ, FRA:S0G, OTC:SGQMF) has started pilot plant beneficiation test work on material from its 100%-owned Araxá Niobium and Rare Earths Project in Brazil, advancing work towards a processing flowsheet capable of producing both niobium and rare earth products.
The program at the CIT-SENAI facility in Belo Horizonte is using about nine tonnes of near-surface saprolite material and is expected to run for four to six weeks, with results anticipated during the fourth quarter of 2026.
The work builds on earlier flotation testing that produced a high-grade niobium concentrate while also upgrading rare earths into the niobium flotation tailings.
Locked-cycle flotation incorporating recycle streams will be used to further optimise recoveries and grades, with additional metallurgical and mineralogical programs underway at laboratories including SGS Lakefield in Canada and Tecnicas Reunidas in Spain.
The large-scale pilot program will use grinding, magnetic separation and flotation to generate a niobium concentrate and a rare-earth-enriched tailings stream.
Niobium concentrate will then undergo downstream testing targeting ferroniobium containing about 65% niobium. Testing will assess pyrometallurgical refining to improve niobium oxide grades and remove contaminants, followed by an aluminothermic process to convert the refined concentrate into ferroniobium.
The rare earth-enriched tailings will meanwhile undergo hydrometallurgical testing targeting an intermediate product such as mixed rare earth carbonate or rare earth oxalate. Previous pilot-scale work on Araxá mineralisation produced rare earth oxalate at greater than 99% purity and achieved overall total rare earth oxide recovery of 86%.
"Our aim is to replicate these strong results in the pilot plant study and continue developing the flowsheet that will be implemented in our own pilot plant being built at CEFET-MG in Araxá," St George executive chair John Prineas said.
"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."
Simplified niobium processing flowsheet highlighting the niobium concentrate and the rare earths enriched niobium flotation tailings.
Separately, construction has started on St George's own large-scale pilot plant at the CEFET-MG Araxá campus, where it will form the foundation of the St George Technological Centre.
The plant is designed for throughput of up to 300 kilograms per hour and will support niobium flotation as well as production of rare earth concentrates, mixed rare earth carbonate and rare earth oxides. Completion is targeted for December 2026, with first operations scheduled for January 2027.
3D model of the proposed St George Technological Centre in Araxá.
Araxá is in Minas Gerais, adjacent to the operations of CBMM, the world's largest niobium producer, in a region with established infrastructure, skilled labour and a long history of commercial niobium production.
St George formally began environmental permitting for a potential mining and industrial operation in August 2026.
The project hosts a JORC mineral resource of 111.2 million tonnes at 3.57% TREO and 0.57% Nb₂O₅, containing around 760,000 tonnes of NdPr oxides and 630,000 tonnes of Nb₂O₅. Of this, 75.2 million tonnes sits in the measured and indicated categories at 3.64% TREO and 0.58% Nb₂O₅.