en.Wedoany.com Reported - Cobra Resources has completed a new round of rare earth drilling at the Boland and Head prospects in South Australia, with the drilling scale now sufficient to support the first Mineral Resource Estimate (MRE) for these two prospects. Meanwhile, during radionuclide testing of its rare earth products, the company found that actinium content exceeded target limits and is now collaborating with the Australian Nuclear Science and Technology Organisation (ANSTO) on actinium suppression tests.
The drilling campaign completed 74 sonic core holes at the Boland and Head prospects, totaling approximately 3,200 meters. Drilling has delineated a continuous high-grade flank approximately 5 kilometers long at the Head prospect, with mineralization open to both the north and south. Approximately 80% of assay and permeability results have been received, with 12 drill holes at the Head prospect still pending. Notable intercepts include: 1.06 meters at 3,607 ppm Total Rare Earth Oxides (TREO) from 18.6 meters depth; 3.8 meters at 1,322 ppm TREO from 26.1 meters depth; and 2.7 meters at 1,458 ppm TREO from 33.3 meters depth.
Cobra Resources Managing Director Rupert Verco stated that these results demonstrate the scale of mineralization, and the company is defining mineralization over large areas across both prospects, which represents only a small portion of its extensive landholding.
Mineralization at the Boland and Head prospects occurs within three stacked formations suitable for In-Situ Recovery (ISR): the shallow Narlaby Sand, the Garford Clay, and the deeper Pidinga Aquifer. Among these, the Pidinga formation is the most mature, with hydrological work completed, exhibiting strong hydraulic head pressure and favorable metallurgical properties. Cobra's target permeability is 1 to 2 meters per day, while scaled bench studies have shown permeability exceeding 8 meters per day. A single simulated tracer test recovered nearly 80% of the injected tracer from an adjacent well within two days. The company plans wellfield spacings of 15 to 25 meters with leach cycles of 30 to 60 days, and its landholding covers a paleochannel system of 3,200 square kilometers.
The Boland prospect is located on license EL7074, 100% held by Cobra's wholly owned subsidiary LAM Wudinna, while the Head prospect is on license EL6784. Alcrest Royalties Australia retains a 1.5% Net Smelter Return (NSR) royalty on future production from licenses EL7074 to EL7078. The company has entered into a Native Title Agreement with the Barngarla people, and heritage surveys have cleared the drilling areas. Four ISR pilot studies have been conducted in South Australia over the past two years, including a uranium pilot project completed by Alligator Energy several hundred kilometers away, with a long-running commercial ISR uranium operation in the same formation. Additionally, Cobra is independently conducting a 24-hour-per-day diamond drilling program at its Manna Hill Copper-Gold project.
Net Acid Producing Potential (NAPP) analysis shows that within the continuous high-grade zone, natural acid production exceeds consumption, with a maximum potential acidity of 60 kg of sulfuric acid per tonne and modeled consumption of 1 to 16 kg per tonne. Reagent acid is a major operating expenditure in Mixed Rare Earth Carbonate (MREC) production. Verco noted that operating costs for a standard rare earth project could be $18 to $20 per kg of MREC, with approximately 30% attributed to acid requirements; significantly reducing acid usage would yield substantial cost savings. The capital intensity of in-situ recovery is only 15% to 20% of hard rock capital costs. For aquifer-confined ISR uranium operations, remediation and liability costs are approximately 28 times lower per pound of uranium produced compared to open-pit strip mining (such as the Ranger uranium mine).
The optimized MREC contains 58.83% TREO, with heavy rare earths comprising 42.9%. Neodymium accounts for 27.5% of TREO, praseodymium 6.7%, dysprosium 3.8%, and terbium 0.7%. Cerium can be precipitated without solvent extraction during the impurity removal process, increasing the heavy rare earth proportion to 43%. Radionuclide analysis of the MREC shows low levels of all radionuclides except actinium, which exceeds target limits. Cobra's target is an initial total resource of 200 to 400 million tonnes at grades greater than 1,000 ppm TREO, with the Pidinga formation expected to contain indicated resources and the overlying formations inferred resources. The initial MRE will incorporate permeability and acid production models as the basis for a scoping study. The company plans field trials in early 2027 to produce larger quantities of MREC and is evaluating a capital-light field demonstration using ANSTO's pilot facilities. Results from the remaining drill holes at the Head prospect are expected to be released in the coming weeks.
