Cobalt Blue Looks to Simplify Halls Creek Development with Core Sampling Program

Cobalt Blue Holdings (ASX: COB) has completed a targeted core sampling program at the Halls Creek base metals project in Western Australia aimed at improving and simplifying the development pathway.

The program builds on a June 2025 scoping study and tested practical opportunities to improve and simplify the proposed multi-stage operation.

That study only considered the recovery of copper and zinc from Stage 1 operations, and so assessing the potential for silver recovery through the heap leach process is therefore a core objective of the company’s upcoming metallurgical test work.

Results from this program will establish achievable silver extraction performance and provide the technical basis for determining whether Cobalt Blue can incorporate silver recovery into the revised Stage 1 flowsheet and economic evaluation.

Proposed Workstreams

The first workstream will focus on optimising a Stage 1 heap leach flowsheet for the Onedin deposit including key parameters relevant to copper-zinc recovery, reagent performance, leach conditions, and downstream processing.

The second workstream will assess whether selected material from Onedin and the nearby Sandiego deposit could be treated through a single heap leach processing operation and evaluate silver recovery as an additional value driver.

If this alternative configuration is supported by test work and future studies, it could allow the company to reduce development complexity and improve capital efficiency.

The deposits could underpin a centralised processing facility capable of accepting future feed from satellite deposits and any regional exploration targets across the wider tenement package.

Therefore, Cobalt Blue regards the development of Onedin-Sandiego as an important foundation for broader regional growth.

Halls Creek Development Case

Chief executive officer Dr Andrew Tong said core sampling represented a key step in strengthening the Halls Creek development case and advancing the project toward the next phase of study work.

“The scoping study established a strong foundation for Halls Creek as a staged copper-zinc opportunity, and we are now focused on testing practical options to improve that development case,” he said.

“Our Broken Hill Technology Centre is a key enabler of this work, providing in-house metallurgical capabilities and flowsheet optimisation expertise.”

“By leveraging the extensive historical core that is available, we are well positioned to progress this work efficiently and assess ways to unlock further value from this project.”

Cobalt Blue is looking to boost its equity at Halls Creek to 75% by progressing a technical and commercial pathway that supports near‑term optimisation and longer‑term regional development opportunities.

To do so, the company needs to spend a further A$1.5 million on the tenements by 30 June 2028.