DevEx Resources (ASX:DEV) metallurgical test work strengthens outlook for the Kennedy Rare Earths Project

DevEx Resources has delivered a substantial advancement in metallurgical understanding at its 100 per cent owned Kennedy Ionic Adsorption Clay Hosted REE Project in Queensland, with new column leach test work confirming strong extraction of critical rare earth elements from within the Inferred Mineral Resource Estimate.

The results reinforce the potential for Kennedy to support a simple heap leach processing route, supported by shallow and unconsolidated clays that commence at surface.

Highlights

• Magnet rare earth recoveries of 67 per cent and 68 per cent from column leach tests.
• Low acid consumption of 6 to 8 kilograms per tonne.
• Minimal cerium recovery of less than 5 per cent.
• Low gangue and impurity extraction relative to rare earth content.
• Column test program completed on a 127 kilogram composite sample drawn from 167 intervals across 68 drill holes.
• Mineralisation situated in soft clays occurring from surface with no overburden.
• Metallurgical work undertaken by ANSTO in consultation with WGA.

The column leach test work follows earlier diagnostic leach studies that showed rapid desorption of rare earth elements using ammonium sulphate solution.

The latest program was designed to assess the suitability of a heap leach processing pathway by examining solution flow characteristics, impurity dissolution and extraction performance for magnet rare earths.

Two columns were packed with agglomerated ore sourced from the homogenised composite sample, each column containing approximately 38 kilograms of mineralised material.

The lixiviant was applied at five litres per square metre per hour over 37 days, followed by a six day water wash.

The test results showed consistent magnet rare earth extractions of 67 per cent and 68 per cent across the two ammonium sulphate concentrations of 0.2M and 0.5M.

Acid consumption remained low at between 6 and 8 kilograms per tonne, and very low cerium extraction indicated selective recovery of the higher value rare earth elements.

The flow of ammonium sulphate solution through the clay rich material was recorded as excellent, supporting the potential for a straightforward heap leach process.

During the later phase of testing, the lixiviant pH was progressively reduced from pH 3 to pH 1.5 to assess the relationship between magnet rare earth extraction and impurity dissolution.

The results showed increased extraction accompanied by higher aluminium dissolution, indicating the trade off between recovery and impurity levels within the leach solution.

The progressive results from the column tests highlight a clear opportunity to optimise acid addition strategies to achieve a balance between high extraction and low impurity dissolution.

The representative composite sample used for the column trials was prepared from 167 individual intervals collected from air core and RAB drill holes located within the Kennedy Inferred Resource.

The composite was screened, crushed and homogenised to form a 127 kilogram sample, with the head grade aligning closely with the higher cut off portion of the Inferred Resource, ensuring the tests reflect the characteristics of the mineralised zone targeted for development.

Kennedy’s geological characteristics support the metallurgical outcomes, with the deposit comprising surficial clays enriched in rare earth elements derived from weathered granitic rocks.

The mineralisation contains praseodymium, neodymium, dysprosium and terbium, which are essential inputs to permanent rare earth magnets used in electric vehicles, wind turbines and other renewable energy applications, and Kennedy remains one of only a select number of defined ionic clay rare earth systems in Australia.

The project is situated across two pastoral properties with existing access agreements in place, enabling efficient engagement with landholders and ongoing exploration activities.

The broader region is supported by established transport networks, power supply and proximity to bulk port facilities.

The results of the column leach program provide a strong foundation for DevEx Resources to advance metallurgical studies at Kennedy, including further optimisation of acid addition, additional mineralogical analysis using XRD techniques and the evaluation of larger scale bulk sampling.

With shallow, unconsolidated clays beginning at surface and favourable leach response demonstrated in preliminary tests, the Company is well positioned to progress the next phase of technical assessment at the Kennedy Project.

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