Cobra's 88% Rare Earth Recovery Peak vs a 48.1% Mean: 7 Things You Need to Know

Wudinna's Maiden Resource & November Leach Results

Cobra Resources (LSE: COBR) reported a maiden Mineral Resource Estimate of 150 million tonnes at 470 parts per million total rare earth oxides (TREO) at its Wudinna Rare Earth Project in South Australia. That total includes material assessed for both in-situ recovery (ISR) and conventional mining, and no Ore Reserve has been estimated. Cobra describes the maiden resource as the foundation for economic evaluation.

Cobra reported leach results on November 5, 2026 from drill return samples taken at the Boland and Head discovery areas and tested by the Australian Nuclear Science and Technology Organisation. The samples underwent a 24-hour, ambient-temperature leach at a hydrogen potential of 3 using a 0.5 molar ammonium sulfate solution. The results include a peak of 88.4% extraction of total rare earths plus yttrium (TREY), a Pidinga Formation mean of 48.1%, and a mean of 69.8% across 3 samples from the Narlaby Formation, which has not yet been shown to be amenable to ISR.

1. Pidinga Extraction Ranged From 4.2% to 88.4%, with a 48.1% Mean

Across 25 samples from the Pidinga Formation, which Cobra describes as amenable to ISR, TREY extraction ranged from 4.2% to 88.4%, with an unweighted mean of 48.1%. Across the full sample set, the unweighted mean TREY extraction was 47.1%. The Pidinga sample that returned 88.4% TREY extraction also returned 81.2% samarium and 75.6% yttrium.

Cobra states that the program identifies both the opportunities and the variability that must be reflected in the Scoping Study. Its next steps include defining metallurgical domains and assessing the relationship between extraction, mineralogy and aquifer permeability.

Managing Director of Cobra Resources, Rupert Verco, described the objective behind the testwork:

"Our strategy is to maximise recoverable value and build an efficient, scalable operation."

2. Dysprosium-Terbium Averaged 50.9% in Pidinga & 72.9% in Narlaby

Within the Pidinga samples, dysprosium-terbium recovery averaged 50.9% and neodymium-praseodymium recovery averaged 48.3%. The Pidinga dysprosium-terbium range ran from 12.2% to 80.6%. In the Narlaby samples, dysprosium-terbium averaged 72.9% and neodymium-praseodymium 71.6%.

Cobra presents Wudinna as a dysprosium and terbium project and describes its target product as containing no cerium and more than 43% heavy rare earths. Its development strategy for Wudinna includes maximizing valuable rare earth recovery and optimizing the product to reduce downstream costs.

3. Narlaby Averaged 69.8% TREY Extraction but Is Not Yet Shown to Be ISR-Amenable

The 3 Narlaby Formation samples from Head returned a mean TREY extraction of 69.8%, with a peak of 88.3% and dysprosium-terbium recovery of up to 92.6%. Cobra describes Narlaby as permeable and mineralized, but it has not yet been shown to be amenable to ISR for resource estimation purposes. The company will study whether Narlaby can be included in the Head ISR resource in whole or in part.

Cobra describes the Narlaby results as an opportunity to move existing open-pit mineralization into ISR-recoverable resources.

4. Recovery at pH 3 & Cobra's Acid Consumption Benchmarks

Cobra's presentation lists recoveries of 25% at pH 7, 44% at pH 5 and 80% at pH 3. The November program ran at pH 3.

Cobra's peer comparison lists Boland at 80% dysprosium-terbium recovery at pH 3 with acid consumption of 6.7 kilograms per tonne. Cobra also cites acid consumption of less than 5 kilograms per tonne and recoveries above 50% with no ammonium sulfate. The company states that, compared with peers, Boland has the highest recoveries at the lowest acid consumption, and that acid usage can be further reduced with natural acid generation.

Cobra lists a recovery versus reagent trade-off evaluation among its next steps, aimed at evaluating optimal economics.

5. A Scaled Bench Study Recovered 66% of Heavy Rare Earth Oxides in 17 Days

A scaled bench study recovered 66% of heavy rare earth oxides in 17 days, with acid consumption of 3.88 kilograms per tonne and permeability above 8 meters per day. Cobra describes metallurgy, geology and permeability as the Wudinna project's advantage to shorten the pathway to production.

Cobra states that Wudinna mineralization is contained in a laterally uniform permeable sand aquifer, which reduces surface infrastructure, and that the hypersaline aquifer has no users. Cobra has prepared a large-scale ISR column to replicate its planned small-scale production study, including precipitation, transport and re-dissolution.

6. Cerium Removal Targets a Higher-Value Product

Cobra's optimized flowsheet leaches at pH 3, removes actinium, cerium and iron at pH 4.5, removes aluminum and uranium at pH 6.2, and precipitates a mixed rare earth carbonate at pH 7.5. The resulting product grades 58.8% TREO, with cerium at about 0.6% of TREO and impurities below 0.9%.

Within that product, neodymium-praseodymium makes up 34.4% of TREO, dysprosium-terbium 4.5% and other heavy rare earths 37.5%. Cobra states that cerium removal preserves the high-value magnet rare earth signal and reduces low-value carbonate mass. Its development strategy targets a higher-value product achieving a market premium and includes qualifying the product with prospective customers.

7. Laboratory Results Still Need Field Confirmation

Cobra classifies the November results as laboratory diagnostic results. Commercial recoveries, costs, saleable product specifications and environmental performance remain subject to further testing and field validation. The diagnostic data will be assessed alongside permeability measurements, intact-core testing and field performance.

Verco set out the steps from laboratory to operation:

"The next step is to establish how these laboratory results translate into an integrated mine plan and field performance."

Cobra plans to operate a small-scale production study in the first quarter of 2027 to validate ISR parameters and support feasibility studies (FS). Its indicative schedule runs from definition and testing in 2027 to validation and preparation in the second half of 2027 and 2028, with milestone-dependent development and execution in 2029. A final investment decision (FID) requires feasibility, approvals, funding and commercial agreements. Cobra states these are indicative planning windows, not committed dates.

Key Takeaways for Investors

The best Pidinga Formation sample returned 88.4% extraction of total rare earths plus yttrium, and the Pidinga mean was 48.1%. Cobra states that the variability identified by the program must be reflected in the Scoping Study. Dysprosium-terbium recoveries averaged 50.9% in the Pidinga Formation and 72.9% in the Narlaby Formation, against 48.3% and 71.6% for neodymium-praseodymium.

The Narlaby Formation returned a mean of 69.8% from 3 samples, and Cobra will study whether this material, which it describes as existing open-pit mineralization, can be included in the in-situ recovery resource. A scaled bench study recovered 66% of heavy rare earth oxides in 17 days with acid consumption of 3.88 kilograms per tonne. Cobra plans a small-scale production study in the first quarter of 2027 to validate in-situ recovery parameters and support FS.