VBX Ltd (ASX: VBX) has reported improved beneficiation outcomes from metallurgical optimisation test work completed as part of the Definitive Feasibility Study (DFS) at its Wuudagu bauxite project in northern Western Australia.
The news sent VBX shares soaring 14.29% to $0.640 by midday trade.
Managing director Ryan de Franck said the results confirmed a material uplift in product mass recoveries at high solids ratios and short residence times, creating scope to lift production capacity by 20%–30% during the DFS phase.
Highlights
- VBX says DFS metallurgical optimisation at its Wuudagu bauxite project has delivered materially improved beneficiation results versus 2025 PFS assumptions
- Product mass recovery lifted by 23% to 72.9% at a +3.35 mm product screen size
- A “volume” strategy using a +1.0 mm screen increased mass recovery by 34% to 79.8%
- Product grades of 44.2%–46.6% Al₂O₃ and 2.6%–4.4% SiO₂ achieved across multiple screen sizes, supporting operational flexibility
- VBX lifts Wuudagu beneficiation recoveries through DFS optimisation
The 2025 pre-feasibility study (PFS) assumed a wet scrubbing and screening flowsheet producing a beneficiated product grading 45.4% Al₂O₃ and 3.6% SiO₂ at a +3.35 mm screen size, with 59.5% mass recovery from the Wuudagu C deposit.
DFS test work has consistently exceeded these assumptions, including at the same screen size, delivering materially higher recoveries under comparable conditions.
“It is well understood that Wuudagu bauxite material is highly amenable to beneficiation through simple, industry standard methods. This has been demonstrated by metallurgical test work conducted by BHP in the 1960’s and by VBX over the past 10 years,” de Franck said.
“These results are very positive because they demonstrate improved beneficiation results than were expected based on the PFS metallurgical test work program.
“Most significantly, we are seeing a material increase in product mass recoveries at high solids ratios and short residence times in the scrubbing test work. This provides an opportunity to increase the production capacity at Wuudagu by 20 to 30% in the DFS before considering any potential increase in the mining rate that could be supported by increasing the size and confidence of the Wuudagu mineral resource.
“Pleasingly, the product quality results from the optimisation test work are consistent with the product quality regressions developed during the PFS. The high quality, low silica product grade at Wuudagu is a key competitive advantage, particularly in an Australian context, given existing bauxite producers are selling products with a significantly higher silica content.
“Commercially, we are seeing continued strong interest from groups who want to buy or market Wuudagu bauxite and we are advancing discussions with groups who are willing to provide funding solutions to secure these rights.”
DFS metallurgical test work program
The first stage of DFS optimisation was completed at Nagrom in Perth, using a 1,500 kg bulk composite sample from the Wuudagu C deposit.
The composite was compiled from 23 bulk samples across 10 of 12 bulk sample sites, covering the vertical profile of the deposit. It averaged 41% Al₂O₃ and 12% SiO₂ in situ and was considered representative of Wuudagu C.
Test work assessed scrubbing performance across solids ratios of 45%, 50% and 55%, and residence times ranging from 1.5 minutes to 12 minutes.
Higher recoveries at short residence times
Mass recoveries in the DFS program were consistently higher than those achieved during PFS test work, including a 23% increase to 72.9% at a +3.35 mm screen size.
Importantly, these recoveries were achieved at a 55% solids ratio and residence times of 1.5–2 minutes, which the company said could reduce scrubbing capacity requirements and lower water use, power consumption, capital costs and operating costs.
“Volume” strategy boosts recoveries
VBX also assessed the impact of reducing final product screen size to capture additional fines material.
Under a “volume”-focused strategy using a +1.0 mm screen, the company achieved 79.8% product mass recovery, representing a 34% increase compared with the PFS recovery case.
VBX noted this approach may appeal to certain offtake and marketing groups, despite the typical trade-off of slightly lower alumina grade and higher silica content.
The company said product quality results from the DFS optimisation aligned with regression models developed during the PFS.
At a +3.35 mm screen size, beneficiated product grades ranged from 45.2%–45.9% Al₂O₃ and 3.2%–3.5% SiO₂ at 55% solids and short residence times.
Across the tested screen sizes, product grades ranged from 44.2%–46.6% Al₂O₃ and 2.6%–4.4% SiO₂, which VBX said provides flexibility to tailor production to market requirements while maintaining Wuudagu’s low-silica profile.
Next steps
Additional scrubbing and screening test work is ongoing on bulk sample composites from the Wuudagu B and Wuudagu C deposits, alongside filtration test work on fines material.
Based on the results to date, VBX has elected to pursue a simplified tyre-driven scrubbing solution, with DFS scrubbing parameters to be selected to optimise product quality while minimising water and power use and reducing overall plant costs.