Gold Mountain’s latest metallurgical tests from its Capivara Prospect in Brazil reveal promising ionic adsorption clay rare earth mineralisation, with extraction rates nearing 66%. New targets at Irajuba add to the project’s expanding footprint.
- Up to 65.9% rare earth extraction from shallow Capivara samples
- Ionic Adsorption Clay (IAC) style mineralisation confirmed
- Three new priority target areas identified at Irajuba
- Metallurgical variability indicates geological complexity
- Further deeper drilling and metallurgical work planned
Capivara Shows Strong Rare Earth Extraction Potential
Gold Mountain Limited (ASX:GMN) has reported metallurgical test results from its Capivara Prospect that underpin the presence of Ionic Adsorption Clay (IAC) style rare earth mineralisation. Testing of shallow auger samples yielded extraction rates of up to 65.9% for Total Rare Earth Elements plus Yttrium excluding Cerium (TREY-Ce), with magnet rare earth elements showing up to 63.6% successful desorption from the upper saprolite zone. These figures suggest a mineralisation style amenable to low-cost, environmentally friendly processing.
Importantly, the current auger drilling has only sampled the upper weathering profile, with indications that deeper saprolite zones may hold even stronger metallurgical responses. This aligns with the favourable extraction rates observed in deeper sections of a 13-metre diamond drill hole (CPAD250007) at Capivara, where lower saprolite samples outperformed near-surface material.
Expanding Targets at Irajuba Highlight Project Scale
Beyond Capivara, Gold Mountain identified three separate areas within the Irajuba Prospect with characteristics consistent with IAC-style rare earth deposits. Clusters of desorption results from auger drilling in the eastern Irajuba area exhibit low levels of deleterious contaminants such as aluminium, iron, and calcium, a critical factor for downstream processing economics.
The Irajuba drill holes tested so far cover a broad 16-kilometre area, underscoring the extensive nature of the mineralised system within the 2,512 km² Down Under Project. The company’s ongoing wide-spaced auger drilling aims to systematically evaluate large-scale TREO stream sediment anomalies, with plans to deploy higher-capacity auger rigs to reach deeper saprolite horizons.
Metallurgical Variability Reflects Geological Complexity
Gold Mountain’s metallurgical testing, conducted by Australia’s ANSTO, reveals significant variability in leaching performance across both prospects. Variations in extraction efficiency and contaminant concentrations suggest differing rare earth mineral associations within the weathering profiles, which will require detailed follow-up to delineate zones with optimal metallurgical characteristics.
Additional acid leaching tests at lower pH levels improved magnet rare earth element extraction but also increased the mobilisation of deleterious elements, raising questions about the economic viability of these conditions. The company emphasises that further metallurgical work will focus on balancing extraction efficiency with reagent consumption and contaminant removal.
Next Steps: Deeper Drilling and Resource Definition
Gold Mountain plans to accelerate deeper auger and diamond drilling around promising zones at Capivara and Irajuba to better understand the vertical distribution and continuity of mineralisation. This work aims to support future JORC Mineral Resource estimation and refine the project’s development potential.
The company’s strategy prioritises rare earth deposits that can be processed with low environmental impact and cost, producing high-quality rare earth products. With 58 samples already tested metallurgically and ongoing exploration across multiple prospects, Gold Mountain is building a robust pipeline of targets within its extensive Brazilian portfolio.
These results build on recent drilling successes that expanded the Irajuba IR-1 resource area over 1.2 kilometres, confirming high-grade rare earth zones with strong magnet rare earth oxide content. The combination of encouraging metallurgical data and broadening exploration coverage suggests a project advancing steadily towards defining economically viable rare earth resources.
Bottom Line?
Gold Mountain’s metallurgical breakthrough at Capivara confirms IAC-style rare earth potential but hinges on deeper drilling and economic assessment of extraction methods.
Questions in the middle?
- Will deeper drilling confirm improved extraction rates and thicker saprolite zones?
- Can Gold Mountain economically manage increased deleterious element removal under stronger acid leaching?
- How will ongoing regional auger drilling refine the pipeline of rare earth targets within the Down Under Project?