St George Mining Launches Dual Niobium and Rare Earths Pilot Plant Program
Key Takeaways
- St George Mining has commenced processing approximately 9 tonnes of near-surface saprolite through a multi-stage flotation program at CIT-SENAI in Belo Horizonte, with results expected in Q4 2026.
- The dual-pathway flowsheet targets both a ferroniobium product (~65% niobium) and a rare-earth-enriched stream, with historical precedent from a 2012/13 program delivering rare earth oxalate at greater than 99% purity and 86% TREO recovery.
- The Araxá Mineral Resource Estimate stands at 111.2Mt @ 3.57% TREO and 0.57% Nb₂O₅ — the largest and highest-grade hard-rock rare earths resource in South America — with EIA/RIMA permitting formally submitted to FEAM in August 2026.
- St George's own large-scale pilot plant at CEFET-MG in Araxá, with throughput capacity of up to 300 kg/hour, is under construction with completion targeted December 2026 and first operation in January 2027.
- The metallurgical team carries direct CBMM pedigree, with the lead processing engineer holding 30+ years of niobium mineral processing experience as former Head of Mineral Processing at the world's largest niobium producer, which operates directly adjacent to the Araxá Project.
St George Mining Limited has commenced pilot plant beneficiation test work at its Araxá Niobium and Rare Earths Project in Minas Gerais, Brazil. Approximately 9 tonnes of near-surface saprolite from the Central Araxá Project area is being processed through a multi-stage flotation program at CIT-SENAI in Belo Horizonte, with the study expected to run for four to six weeks and results anticipated in Q4 2026.
What the pilot plant study is designed to achieve
The study is built around a two-track processing objective: producing a niobium concentrate and generating a rare-earth-enriched tailings stream that can be evaluated independently. Both commodity streams will then progress through separate downstream test work programs. The approach mirrors the processing principles used by CBMM, the world’s largest niobium producer, which operates directly adjacent to St George’s Araxá Project.
The flowsheet follows a clear sequence from the bulk sample through grinding and magnetic separation, with magnetic separation isolating iron-bearing tailings, and a subsequent niobium flotation stage separating the remaining material into a niobium concentrate and a rare-earth-enriched tailings stream.
Niobium pathway
The niobium concentrate produced from the pilot plant will be advanced through downstream pyrometallurgical processing. The proposed test work involves refining the concentrate in an electric arc furnace to increase niobium oxide grade and remove contaminants including lead and phosphorus. This is followed by an aluminothermic conversion process to produce ferroniobium containing approximately 65% niobium. This route is consistent with standard industry processing for Araxá-style pyrochlore mineralisation.
Rare earths pathway
The rare-earth-enriched niobium flotation tailings will be evaluated through hydrometallurgical test work targeting an intermediate product, either mixed rare earth carbonate (MREC) or rare earth oxalate. Historical precedent from the 2012/13 pilot plant program on Araxá mineralisation provides de-risking context: that program produced rare earth oxalate at greater than 99% purity with an overall TREO (total rare earth oxide) recovery of 86%, indicating the mineralisation is amenable to production of a high-grade rare earths product.
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Understanding niobium and rare earth beneficiation, and why it matters for investors
Beneficiation refers to the process of upgrading raw ore into a sellable or refinable concentrate — essentially transforming mined material into something that can be processed or sold into downstream markets. The strategic value here is that St George is developing a dual-commodity flowsheet capable of producing two separate product streams from a single mining operation.
Ferroniobium is a high-strength steel alloy additive used extensively in construction, automotive, and pipeline infrastructure. NdPr-bearing rare earths (neodymium-praseodymium) are critical inputs for permanent magnets used in electric vehicles and wind turbines. Running two parallel downstream programs simultaneously reduces timeline risk compared with a sequential approach, and a dual-commodity process flowsheet has the potential to materially improve project economics versus a single-commodity operation.
World-class team and multi-lab test program underpin technical credibility
The metallurgical team assembled for this program carries deep CBMM pedigree across several key roles. Ricardo Nardi, Lead Processing Engineer, is a former Head of Mineral Processing at CBMM with more than 30 years’ experience in niobium mineral processing. Adriano Rios, Director of Operations, is a former Production Manager at CBMM and former Director of Operations for COMIPA, the joint venture operating company between CBMM and the State of Minas Gerais. Alaercio Vieira, Metallurgy Manager, previously held the Metallurgy Manager role at Serra Verde, currently Brazil’s only producing rare earths mine. Independent oversight is provided by IMO’s Peter Adamini and Gavin Beer, both serving as Competent Persons for test work results.
| Expert | Role at St George | Previous Organisation | Key Credential | Relevance |
|---|---|---|---|---|
| Ricardo Nardi | Lead Processing Engineer | CBMM | Former Head of Mineral Processing; 30+ years’ niobium experience | Deep technical knowledge of Araxá-style pyrochlore processing |
| Adriano Rios | Director of Operations | CBMM / COMIPA | Former Production Manager and Director of Operations | Full mining and pyrometallurgy operational experience at adjacent operation |
| Thiago Amaral | Brazil Country Head | CBMM | Former Product Regulation Coordinator and Head of Sustainability | Quality control, environmental licensing, and ESG expertise |
| Alaercio Vieira | Metallurgy Manager | Serra Verde / Taboca / CBMM / CMOC | Metallurgy Manager at Brazil’s only producing rare earths mine | Rare earths and niobium processing across multiple operations |
| Carlos Araujo & Juliano Bianco | Chief Plant Engineer / Specialist Engineer | CBMM / Mosaic Company | Managed design, construction and commissioning of CBMM’s niobium processing plant | Pyrochlore and monazite processing plant expertise for own pilot plant build |
Testing is being conducted across multiple international laboratories in parallel, including CETEM, SGS Belo Horizonte, SGS Lakefield Canada, Auralia in Perth, and Tecnicas Reunidas in Spain. This multi-laboratory approach allows direct comparison of process performance and repeatability, reducing single-lab uncertainty and strengthening the scientific credibility of the results.
John Prineas, Executive Chairman
“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.”
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Own pilot plant and project-level context
Beyond the CIT-SENAI study, St George is constructing its own large-scale pilot plant at CEFET-MG (the Federal Center for Technological Education of Minas Gerais) in Araxá. The facility will have a throughput capacity of up to 300 kg/hour and is being developed as the foundation of the new St George Technological Centre at CEFET’s Araxá Campus. Environmental and building permits have been received, construction has commenced, and completion is expected by December 2026, with first operation of the pilot plant targeted for January 2027. Construction is being managed by St George’s in-house plant engineers alongside feasibility technical adviser Worley.
At the project level, the Araxá resource underpinning this work is substantial. The Mineral Resource Estimate (MRE), upgraded in August 2026, established Araxá as the largest and highest-grade hard-rock rare earths resource in South America. The total MRE stands at 111.2Mt @ 3.57% TREO and 0.57% Nb₂O₅, containing 760,000t of NdPr oxides and 630,000t of Nb₂O₅. Environmental Impact Assessment (EIA) and Environmental Impact Report (RIMA) permitting was formally submitted to the State Environmental Foundation of Minas Gerais (FEAM) in August 2026.
| Resource Classification | Million Tonnes (Mt) | TREO (%) | NdPr (%) | Nb₂O₅ (%) |
|---|---|---|---|---|
| Measured | 33.2 | 3.81 | 0.72 | 0.63 |
| Indicated | 42.0 | 3.50 | 0.67 | 0.54 |
| Measured & Indicated | 75.2 | 3.64 | 0.69 | 0.58 |
| Inferred | 36.0 | 3.43 | 0.66 | 0.53 |
| Total | 111.2 | 3.57 | 0.68 | 0.57 |
MRE classified and reported in accordance with JORC Code (2012). Effective date: 11 August 2026. The entire MRE is potentially amenable to open pit mining based on depth and geometry, lying within approximately 120m of surface. No ore reserve or detailed mine design is reported.
Key upcoming catalysts for the project include:
- Q4 2026: Pilot plant beneficiation test work results from CIT-SENAI
- December 2026: Expected completion of the St George Technological Centre construction at CEFET-MG, Araxá
- January 2027: Targeted first operation of St George’s own pilot plant
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