Breakthrough Leaching Techniques Drive 96% Copper Recovery at Elizabeth Creek
Coda Minerals has unveiled promising results from metallurgical testwork that could significantly enhance the economics of its flagship Elizabeth Creek Copper-Cobalt Project in South Australia, with new leaching techniques delivering copper recoveries of up to 95.9% – a substantial improvement over the project's current 82.8% recovery rate.
Revolutionary Processing Method Slashes Capital Requirements
The company's tests on two whole-ore leach techniques have demonstrated exceptional results for its Emmie Bluff deposit, with both methods eliminating the need for complex flotation circuits and specialized processing equipment in favor of simpler infrastructure.
Key findings include:
- Ammonium chloride leach achieved 95.9% copper recovery after just 8 hours
- Catalyzed ammonia leach delivered 92.5% copper recovery in the same timeframe
- Silver recovery using ammonium chloride reached an impressive 97.3%
- Coarse grind size (75μm) still delivered excellent results, further simplifying processing requirements
"Elizabeth Creek already demonstrates robust fundamentals, with a published post-tax NPV(7) of $802 million and an IRR of 28%. Improving recoveries is the single most powerful lever we can pull. Every percentage point gained translates directly into increased revenue over the life of mine."
— Chris Stevens, CEO, Coda Minerals
The breakthrough has significant implications for both capital and operating expenses, as the whole-ore leach approach would replace complex processing equipment with simple polycarbonate tanks, potentially reducing overall project costs substantially.
Understanding Whole-Ore Leaching: A Simpler Path to Higher Recoveries
Traditional processing at copper projects often relies on flotation to concentrate the valuable minerals before further processing. This approach typically leads to some loss of recoverable metals in tailings – in Coda's case, around 18% of contained copper.
Whole-ore leaching bypasses this step by applying the leaching solution directly to the entire crushed ore body. The technique is particularly well-suited to the carbonate-rich ore at Emmie Bluff, as both leaching methods operate in near-neutral or alkaline conditions.
How Whole-Ore Leaching Works
In conventional copper processing, ore is first concentrated through flotation before the concentrate is further processed to extract metals. This multi-stage approach involves complex equipment and inevitably results in some metal losses at each stage.
Whole-ore leaching simplifies this process by:
- Crushing and grinding the ore to an optimal size (in this case, 75μm)
- Applying leaching solution directly to the entire crushed material
- Dissolving target metals into solution without prior concentration
- Recovering metals from solution through subsequent processing
The two methods tested by Coda operate differently but achieve similar results:
- Catalyzed Ammonia Leach: Uses a readily available, low-cost catalyst in ammonia solution to promote and accelerate sulphide oxidation at 70°C
- Ammonium Chloride Leach: Uses ammonium chloride solution at 90°C with air sparging to oxidize and dissolve copper minerals
Both methods are particularly effective for carbonate-rich ores like those at Emmie Bluff, where the near-neutral or alkaline conditions help prevent acid consumption by carbonate minerals.
Pathway to Production: Next Steps and Timeline
Coda is now advancing on multiple fronts to integrate these findings into its development plans:
- Rapidly progressing OPEX and CAPEX estimation work
- Conducting trade-off studies comparing whole-ore leach to the current base case flowsheet
- Continuing optimization of cobalt leaching, which is currently underway
- Integrating findings into the ongoing Pre-Feasibility Study (PFS)
The company's strategy remains focused on advancing Elizabeth Creek to a construction-ready state, with technical studies, economic assessments, and approvals in place.
Cobalt Recovery Strategy
While copper and silver have demonstrated excellent recovery rates in the initial testing, Coda is also focused on optimizing cobalt recovery. The company is investigating a second-stage reducing leach using various lixiviants to enhance cobalt recovery, which was not extracted in the initial oxidizing phase of either leaching method.
Cobalt in the deposit is hosted in carrollite, which has historically demonstrated strong flotation performance (75-90% recoveries in the most recent Scoping Study update), providing multiple viable pathways for its extraction.
Investment Case Strengthened by Higher Recoveries
The Elizabeth Creek project already boasted compelling economics in Coda's most recent Scoping Study, which demonstrated a pre-tax NPV7 of approximately A$1.2 billion and an estimated All-in Sustaining Cost (AISC) of US$1.80/lb of copper.
These new metallurgical findings could materially enhance these already robust numbers. With copper and silver prices at historically strong levels, the timing of these breakthroughs appears particularly favorable.
The project's resource base includes:
- Emmie Bluff: 40.2Mt @ 1.27% copper, 569ppm cobalt, 17g/t silver
- Windabout: 17.7Mt @ 0.8% copper, 490ppm cobalt, 8g/t silver
- MG14: 1.8Mt @ 1.2% copper, 330ppm cobalt, 14g/t silver
- Cattle Grid South: 5.8Mt @ 0.6% copper, 120ppm cobalt, 3.5g/t silver
Recent Exploration Results
Beyond the metallurgical breakthroughs, Coda has also reported recent drilling results that confirm mineralization outside the main basin that hosts the Emmie Bluff Mineral Resource. Drillhole DD25EB0038 intersected 0.76m @ 0.81% copper from 435.6m, indicating potential for resource growth in several directions.
Why Investors Should Track Coda Minerals
Coda's Elizabeth Creek project offers a compelling investment proposition that has just become significantly more attractive:
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Enhanced Economics: The breakthrough in recovery rates could materially improve project returns, with every percentage point gained in recovery translating directly to increased revenue over the life of mine.
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Tier 1 Jurisdiction: Located in South Australia's productive Olympic Copper Province, just 100km south of BHP's Olympic Dam mine and 15km from its Oak Dam West Project.
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Growing Resource Base: Recent drilling at Emmie East has confirmed mineralization outside the main basin, highlighting growth potential beyond the current 1 million tonne copper equivalent resource.
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Processing Simplification: Whole-ore leaching could substantially reduce capital requirements by replacing complex flotation plants, Albion circuits, and oxygen plants with simpler polycarbonate tanks.
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Strong Copper Market: The project is advancing amid favorable copper price forecasts, driven by electrification and renewable energy transitions.
Development Optionality
The breakthrough in processing technology creates multiple new strategic pathways for project development, including:
- A lower-CAPEX, fast-start scenario focused on early copper and silver production
- Potential to re-optimize open pit designs to enable a larger Stage 1 development
- Greater flexibility to stage the project and maximize value over time
Key Takeaway:
"Coda Minerals has positioned itself with a significant copper-cobalt project in a premier mining jurisdiction, now enhanced by breakthrough metallurgical results. With a clear pathway to development and a simplified processing route that could deliver recoveries approaching 96%, Elizabeth Creek represents one of the most compelling emerging copper development stories on the ASX."
Ready to Capitalise on One of Australia's Most Promising Copper Opportunities?
Discover how Coda Minerals' breakthrough leaching techniques could transform the economics of the Elizabeth Creek Copper-Cobalt Project, potentially delivering copper recoveries of up to 95.9%. With a published post-tax NPV(7) of $802 million already established, every percentage point gained in recovery translates directly to increased project value. For more information about this compelling investment opportunity in South Australia's productive Olympic Copper Province, visit www.codaminerals.com today.
