Cyprium Metals Heap Leach Tests Match Resource Model Ahead of Q4 2026 First Copper
Key Takeaways
- Grade control drilling across 24 wells reconciled within +/- 5% of the Mineral Resource block model, giving the near-term mine plan firmer ground.
- Target direct injection rates were achieved on Pad 6, with lower pressure injections exceeding targets and monitoring wells confirming heap permeability.
- Acid consumption averaged 4.25 g/l with a copper-to-acid ratio of 1:4.25, in line with or better than modelled PFS assumptions.
- 212 wells now access about 1.7 million tonnes of material, supporting an estimated six to eight months of leaching.
- High voltage power is connected to the SXEW plant, and first copper cathode remains on track for Q4 2026.
Heap leach commissioning hits early milestones at Nifty
Cyprium Metals (ASX: CYM / OTCQB: CYPMF) has reported initial leaching and commissioning milestones at the Nifty Copper Complex in Western Australia’s Paterson region, with the heap leach area “ramping steadily towards operations.”
For investors, the point is simple. The company is testing its operating assumptions on live ore before the solvent extraction and electrowinning (SXEW) plant starts up.
Three headline points stand out:
- Grade control drilling reconciled within +/- 5% of the Mineral Resource block model.
- Target injection rates and volumes were achieved on Pad 6.
- High voltage power is now connected to the SXEW infrastructure, with wet commissioning and first cathode on track for Q4 2026.
Executive Chairman Matt Fifield framed the results as validation of the plan.
Matt Fifield, Executive Chairman
“It is exciting to see the early results of heap leach commissioning so quickly validating our operating assumptions…”
“…This is another foundational moment as we continue to build Australia’s next great copper company.”
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Grade control drilling validates the resource model
Grade control drilling checks whether the ore in the ground matches what the resource model says is there. A close match means the mine plan rests on firmer numbers.
212 wells and 1.7 million tonnes in place
Following the August direct injection field trial, Cyprium completed and cased an additional 198 production and monitoring wells across Heaps 13 to 16 on Pad 6. That brings the total to 212 wells.
The production area accesses approximately 1.7 million tonnes of material. This is expected to support approximately six to eight months of leaching activity, and additional production blocks will be drilled, cased and commissioned as operations deplete the existing area.
Composite samples from 24 wells were assayed and reconciled within +/- 5% of block model grades in Cyprium’s Mineral Resource estimates for the existing Nifty heaps, released on 19 August 2024. The company called this “an important validation.”
What that tells you is that the grade assumptions behind the near-term mine plan are holding up against direct sampling.
Injection results match leach chemistry expectations
Target direct injection rates and volumes have been achieved in the initial Block 1 production area. For lower pressure injections, those targets were exceeded.
Fluid flows are also being seen in monitoring wells as expected. According to the company, this is further confirmation that the existing Nifty heap has adequate permeability and connectivity to use the direct injection leach method.
| Metric | Result | Context |
|---|---|---|
| Free acid injected | 5 to 7 g/l | Weak acid solution; free acid is acid available to extract copper |
| Average acid consumption | 4.25 g/l | Initial results; aligned to baseline assumptions |
| Copper concentration increase | Roughly 1 g/l, to approximately 1.3 g/l | Off-flow solution; typical intermediate leach solution (ILS) grade |
| Copper to acid ratio | 1 : 4.25 | Average ratio of copper produced to acid consumed |
| ILS recirculation target | 2.5 g/l or higher | Adequate for recovery and concentration in the solvent extraction plant |
The acid and copper figures are described in the announcement as approximate and are drawn from its charts.
The company said the observed acid consumption and copper-to-acid ratio are within the range of earlier column testing results in the Nifty pre-feasibility study (PFS). It also said they are “in line with or better than” its modelled assumptions.
Early results do not guarantee future results, as the announcement itself cautions.
What is direct injection leaching?
Direct injection leaching applies leach solution directly into selected zones within an existing heap leach pad through wellbores. Rather than relying solely on surface irrigation and gravity-driven percolation from the top, solution is delivered under controlled pressure to targeted horizons within the heap.
Cyprium’s planned cycle works as follows:
- Pre-condition the targeted material.
- Inject solution at high pressure to quickly saturate material within a radius of the wellbore.
- Follow with lower pressure applications to move larger volumes of solution through the stimulated material.
- Rotate to non-active wells, then return to the first area to repeat the cycle until the wells reach economic cutoff.
The company says this method has the potential to materially improve the operational flexibility of the heap leach restart. It also reaches higher-grade areas lower in the heaps that would otherwise sit near the end of the mine life in a traditional surface re-leaching operation.
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Next steps: scaling leach volumes ahead of SXEW
Leaching solution is currently being delivered to Blocks 1 and 3. Over the next few weeks, Fifield said the company will expand the leaching footprint across multiple areas of the heaps to match its targeted rates.
Copper in solution inventory is expected to build progressively to support wet commissioning of the SXEW plant. Pre-commissioning activities on the plant are accelerating now that high voltage power is connected, and first copper cathode production remains on track for Q4 2026.
The Nifty restart is progressing in phases, with solution grade building ahead of the SXEW plant. The next test is whether the company can scale injection volumes across more of the heaps to match its targets.
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