Cobalt Blue has completed a key metallurgical sampling program at its Halls Creek Project, setting the stage for an updated Scoping Study and increasing its interest to 75%.
- 870 kg of core sampled from Onedin and Sandiego deposits
- Metallurgical testwork to optimise heap leach flowsheet and assess silver recovery
- Retained 51% JV interest and exercised option to increase to 75% by 2028
- Updated Scoping Study targeted for Q4 2026
- Potential for simplified development and regional processing hub
Metallurgical Sampling Targets Development Optimisation
Cobalt Blue Holdings (ASX:COB) has taken a significant step forward at its Halls Creek Project in Western Australia's Kimberley region, completing a targeted core sampling program to underpin metallurgical testwork. The company collected approximately 870 kilograms of material from the Onedin and Sandiego deposits, aiming to optimise the Stage 1 heap leach flowsheet and explore a combined heap leach route for both deposits. Notably, the program also assesses the potential recovery of silver, a new value lever not included in the June 2025 Scoping Study, which focused solely on copper and zinc.
JV Earn-In Secures Majority Interest
In parallel with technical progress, Cobalt Blue has met the minimum A$500,000 expenditure threshold required to retain its 51% beneficial interest under the Halls Creek Project Earn-in agreement. The company has now exercised its right to increase its stake to 75% by committing an additional A$1.5 million in expenditure by June 2028, with costs associated with the upcoming Scoping Study and Pre-Feasibility Study (PFS) counting towards this earn-in. This solidifies Cobalt Blue’s control over the project and aligns financial commitment with advancing the technical development pathway.
Updated Scoping Study to Incorporate Metallurgical Insights
The metallurgical program is designed not just to refine the existing heap leach process at Onedin but also to evaluate whether a single heap leach operation could treat material from both Onedin and Sandiego deposits. If successful, this could simplify the development pathway, reduce capital expenditure, and improve operational efficiency. The results will feed into an updated Scoping Study targeted for completion in Q4 2026, which will also incorporate silver recovery potential. Following the Scoping Study, Cobalt Blue intends to progress to a PFS phase, further de-risking the project.
Strategic Regional Development Potential
Beyond near-term optimisation, the Halls Creek Project is viewed as a potential foundation for a regional processing hub. The Onedin and Sandiego deposits could underpin a centralised facility capable of processing feed from satellite deposits and exploration targets across the broader tenement package. This regional approach aims to enhance infrastructure utilisation and scale, offering a more integrated and efficient development model. Cobalt Blue’s in-house Broken Hill Technology Centre plays a pivotal role in advancing these metallurgical and process development efforts.
Robust Geological and Historical Data Support
The announcement confirms no new drilling was undertaken for the metallurgical sampling, which relied on extensive historical diamond core from 2021 and earlier programs. The drilling and sampling data underpinning the project are comprehensive, with detailed logging, assay, and density measurements supporting Mineral Resource estimates for both deposits. While some historical assay data quality issues were noted, these are not expected to materially affect the current development pathway or upcoming study outcomes.
Bottom Line?
Metallurgical testwork and JV milestones position Halls Creek for a critical development update in Q4 2026, but investors should watch for how silver recovery impacts economics.
Questions in the middle?
- Will metallurgical testwork confirm the feasibility of a combined heap leach operation for Onedin and Sandiego?
- How significant could silver recovery be as an additional revenue stream in the revised development plan?
- What are the key risks or uncertainties that could affect the timing or outcome of the updated Scoping Study and PFS?