OD6 Metals (ASX: OD6) – Heap Leaching Validated as Lower-Cost Pathway for Splinter Rock Rare Earth Story
- Noel Ong
- Sep 18
- 6 min read
Announcement
OD6 Metals Limited (ASX: OD6) has released results from its CPC Engineering Optioneering Study, confirming that heap leaching is the lower-cost and preferred primary leach option for the Splinter Rock Rare Earth Project (Figure 1). This is a significant step in de-risking the project and optimising development economics, with the study showing heap leach delivers superior recovery, lower capital intensity, and simplified operations when compared to conventional agitated tank leaching.
Figure 1: The Splinter Rock Rare Earth Project (source: OD6)
Key Highlights - Beginning of the Rare Earth Story
Heap Leach Confirmed as Preferred Route: CPC Engineering’s multi-criteria assessment validates heap leaching as the lower-cost option for clay-hosted REE mineralisation.
Higher Recovery Potential: Heap leach shows superior rare earth recovery compared with tank leach, enabling more MREC production per tonne processed.
Lower CAPEX Profile: Eliminates the need for large leach tanks, clay washing, and complex separation circuits. Modular design allows for scalable, staged construction.
Lower OPEX Drivers: Energy and maintenance costs are reduced; the inclusion of a Chlor-Alkali Facility allows on-site reagent generation and acid recycling.
Premium MREC Product: The downstream process flowsheet (heap leach + nanofiltration + ion exchange + impurity removal) is designed to deliver a high-quality, low-impurity Mixed Rare Earth Carbonate (MREC).
Strategic Partnerships: Ongoing collaboration with ANSTO and CPC Engineering, guiding development pathway decisions.
Upcoming Drill Campaign: Twin-hole diamond core drilling to provide 1.5–2.5t of REE-bearing material for advanced ANSTO testwork.
Techno-Economic Review & Peer Benchmarking
OD6 assessed multiple flowsheet options against criteria such as recovery, circuit complexity, capital and operating costs, product quality, and scalability (Figure 2). Benchmarking shows OD6 sits mid-range among ASX peers on capital intensity, with potential upside once stripping ratios and reagent cost efficiencies are finalised.
Key observations:
Simplicity and Expandability: Heap leach reduces system complexity and allows for staged pad expansions.
Operating Advantage: Lower energy demand and mechanical maintenance; acid recycling and CAF integration further enhance cost profile.
Market Alignment: Uranium and thorium removal steps ensure transport compliance and widen potential markets (Asia, Europe, US).
Figure 2: Peer Comparison Table – Heap Leach vs Tank Leach Projects (source: OD6)
Metallurgical and Study Progress
OD6, CPC, and ANSTO have successfully demonstrated a multi-stage pathway (Figure 3) from heap leach through to final MREC/MREH precipitation, with key steps including:
Figure 3: Indicative Processing Steps – Heap Leach, NF, IX & Impurity Removal (source: OD6).
Heap Leach: Low-acid leach to generate enriched solution.
Nanofiltration: Acid recycling and REE concentration.
Ion Exchange: Further concentration and impurity reduction.
Impurity Removal: Eliminates deleterious elements (Al, Fe, U, Th).
Precipitation: Produces premium, low-impurity MREC/MREH.
Chlor-Alkali Facility: Provides reagent supply security and lowers OPEX (Figure 4).
Figure 4: Example of two BICHLOR™ Electrolysers utilised to produce H2 (g) + Cl2 (g) + 2NaOH (aq) (source: OD6)
The final MREC/MREH product contains elevated Nd, Pr, Dy, and Tb – highly sought-after magnet rare earths critical for global EV and wind turbine supply chains.
Managing Director Brett Hazelden commented:
“The work being conducted by CPC’s optioneering study confirms what our ANSTO testwork and flowsheet work have indicated – heap leaching combined with our innovative downstream steps appears to be the most capital-efficient and operationally simple route to unlock value at Splinter Rock.
Importantly, when benchmarked against other peers in the industry, it suggests a lower CAPEX profile is possible after removing the complex and expensive solid-liquid separation steps in an agitated tank leach process. Notably, integration of our impurity removal steps and a Chlor-Alkali Facility (CAF) suggests a lower capital cost outcome and supports production of a high-value MREC product.
We’ll now move quickly to commence scale up testwork to optimise the Heap Leach and Impurity Removal conditions and produce MREC samples for testing and offtake discussions.”
Next Steps
Scale-Up Testwork: Heap leach and impurity removal optimisation using 1.5–2.5t bulk samples; expected to yield ~1kg of MREC for offtake discussions.
Offtake Partner Engagement: Initiating commercial payability discussions for MREC and MREH.
Government & Financing Engagement: Ongoing dialogue with government bodies and potential financiers.
Exploration & Drilling: September campaign to deliver high-quality core for testwork and resource updates.
Samso Concluding Comments
This is a very interesting release as the Heap leach validation could be a major milestone for OD6, as it positions Splinter Rock as a competitive and scalable rare earths project in a global market hungry for magnet REEs. The decision to focus on a lower-cost, modular, and technically robust solution will materially improve project economics.
From an investor’s point of view, this milestone will significantly de-risk the project’s processing route, assuming all the numbers do indeed stack up. As an avid follower of the OD6 story, this will start to move OD6 closer to producing a high-value MREC product that aligns with global magnet rare earth demand. The upcoming drill program and bulk testwork will be key to translating these study outcomes into a full feasibility case.
The value of OD6 will be further enhanced by the fact that competitors in this area are decreasing. If OD6 comes to fruition, I believe it will lead to substantial value creation for shareholders, as it will essentially be a situation of being the last one standing. However, I think this will likely not happen in the short term, and the ongoing efforts to make the business viable will be crucial for potential investors and current shareholders when considering their future decisions.
As always, #SamsoNews reminds investors that the project remains at a study and testwork stage, with further exploration and feasibility work required before production decisions.
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