Anax Metals Upgrades Heap Leach Study to Add Upside to $501M NPV Project
Key Takeaways
- Anax Metals (ASX: ANX) is upgrading its Whim Creek Heap Leach Scoping Study to a full Feasibility Study, targeting completion in Q1 2027, adding a second processing pathway on top of the already-confirmed concentrator base case.
- The concentrator project's February 2026 DFS Update confirmed a pre-tax NPV(7) of A$501M, IRR of 98%, free cashflows of A$723M over a 10-year mine life, and a payback period of just 14 months — on a 100%-project basis.
- CSIRO-validated 1.0m column leach testwork confirmed copper extraction of 77–80% and zinc extraction of greater than 90% from lower-grade ores, providing the metallurgical foundation for the Feasibility Study.
- Existing permitted heap leach infrastructure is already in place at Whim Creek, reducing regulatory de-risking burden and compressing the study timeline.
- Anax's proprietary preconcentration and bioleaching technology is being developed for both direct application at Whim Creek and potential future commercialisation, creating value beyond a single project.
Anax Metals upgrades heap leach study to feasibility level at Whim Creek
Anax Metals (ASX: ANX) announced on 3 September 2026 that it will upgrade its September 2023 Whim Creek Heap Leach Scoping Study to a full Feasibility Study, adding a potential second processing pathway on top of an already-confirmed robust concentrator project.
The concentrator project’s economics, confirmed in the February 2026 DFS Update, set a strong baseline. On a 100%-Project basis (Anax holds an 80% interest), the DFS Update reported a pre-tax NPV(7) of A$501M, an IRR of 98%, free cashflows of A$723M over a 10-year mine life, an all-in development cost of approximately A$91M, and a payback period of just 14 months. The heap leach circuit now being studied is additional to this base case, not a replacement for it.
Managing Director Geoff Laing
“While our immediate focus is advancing the concentrator project to development, with Front-End Engineering Design (FEED) and financing discussions advancing well, the heap leach opportunity provides upside potential to the compelling base case concentrator project. The combination of existing permitted heap leach infrastructure along with larger-scale column testwork provides an important platform for this Study, which will incorporate enhanced processing strategies, current costs and metal prices. In addition, the Company plans to advance the valuable sorting and leaching IP towards commercialisation.”
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What’s inside the heap leach feasibility study
The proposed Feasibility Study covers six distinct work streams:
- Incorporation of the larger-scale (1.0 m) column test results, including revised copper extraction assumptions of 77–80% and zinc extraction of >90%, plus updated leach kinetics.
- Assessment of potential process enhancements, including investigation of pyrite leaching.
- Updated copper, zinc and foreign exchange assumptions consistent with the base case adopted in the February 2026 DFS Update, together with sensitivity analysis around these inputs.
- Re-based capital cost estimates for the heap leach circuit, SXEW plant and zinc sulphate processing plant, together with updated operating cost estimates.
- Refinement of the heap leach production schedule and its integration with the broader Whim Creek development schedule.
- Assessment of marketing and offtake options for copper cathode and zinc sulphate crystal product.
One practical advantage worth noting: existing permitted heap leach infrastructure is already in place at the Whim Creek site. That reduces the de-risking burden for the study, since the regulatory groundwork has already been laid.
Why bioleaching matters — and why Anax is developing it
The majority of the world’s copper is locked in primary sulphide minerals, with chalcopyrite the dominant form. Standard heap leaching does not work well on these primary sulphides, which is precisely why there is an active global effort to commercialise viable leaching routes for sulphide copper. Bioleaching uses naturally occurring microorganisms to accelerate the oxidation of sulphide minerals, unlocking copper recovery from lower-grade material that would otherwise be uneconomic to process.
Anax’s proprietary preconcentration and bioleaching technology sits squarely in this space. It is being developed for direct application at Whim Creek and is also being prepared for potential future commercialisation, giving the technology value beyond a single project.
CSIRO testwork validates the approach
The technical foundation for this Feasibility Study is not speculative. Larger-scale 1.0 m column leach testwork conducted at CSIRO, referenced from the 29 January 2025 announcement, confirmed copper extraction of 77–80% and zinc extraction of >90% from lower-grade ores. These results feed directly into the study scope, providing the metallurgical data that underpins the recovery assumptions and leach kinetics to be incorporated.
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Timeline, next steps and the path to Q1 2027
Anax has outlined a clear sequence of near-term activity:
- Immediately commencing the update of the previous scoping study with CSIRO column testwork technical data and advancements in the bioleaching technology.
- Capital and operating cost update to follow, supported by engineering consultants EPCM and CPC.
- Feasibility Study expected to be completed in Q1 2027.
- FEED and financing discussions on the concentrator project continuing in parallel.
The dual-track nature of the opportunity is worth holding in mind. The concentrator project remains the primary development path, with FEED already commenced and financing discussions underway. The heap leach Feasibility Study is intended to quantify the additional value that integrated preconcentration and bioleaching could deliver, layered on top of those already-confirmed standalone economics. At this stage, the heap leach represents a study outcome, not a confirmed development decision.
| Processing Pathway | Ore Type Targeted | Key Technology | Study Status | Potential Output |
|---|---|---|---|---|
| Concentrator (base case) | High-grade sulphide ore | Conventional flotation | DFS Update completed February 2026; FEED commenced | Base metal concentrate |
| Heap Leach (upside) | Low-grade and transitional ore | Preconcentration and bioleaching (proprietary) | Feasibility Study commencing; expected completion Q1 2027 | Copper cathode; zinc sulphate crystal |
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