Axel REE (ASX: AXL) has selected the Woolrich deposit in Area B of its Caladão project in Brazil’s Lithium Valley as the site of its inaugural field trial for in situ recovery (ISR) of rare earth elements.
The decision shifts the company from exploration and laboratory metallurgical work into field-scale ISR program development.
The test was designed to generate pregnant leach solution under realistic operating conditions and supply it to Core Resources in Australia for downstream mixed rare earth carbonate production.
Woolrich was chosen after earlier magnesium sulphate leach work confirmed metallurgical characteristics consistent with an ionic-adsorption clay system and pointed to a deposit that can support the move from auger and laboratory results into a functioning wellfield model.
Moving ISR Program into Development
The field trial – which will take place within a defined area of about 2 hectares inside the Woolrich ISR deposit – is designed to generate the operating parameters needed for wellfield and process design.
These include permeability response, reagent consumption, pregnant leach solution tenor, recovery behaviour, hydraulic control, and impurity management under field conditions.
Axel REE is assembling a multidisciplinary technical team spanning geology, hydrogeology, geotechnical support, engineering, environmental co-ordination, and specialist consulting disciplines needed to design, install and monitor the program.
The selected area offers low-relief topography to support gravity-assisted pregnant leach solution drainage, a well-developed lateritic regolith profile over coarse pegmatitic granite for leachant distribution, and fresh bedrock beneath the mineralised zone that is expected to act as a natural hydraulic boundary.
The chosen location also sits close to the highest-grade auger intersections from the November 2025 leach test program, giving the company a technically favourable starting point for its first field installation.
Metallurgy Underpins Woolrich Selection
Woolrich previously returned soluble total rare earth oxide (TREO) grades averaging 464 parts per million from initial magnesium sulphate leach tests, a level the company noted compares closely with the 486ppm soluble TREO grade reported at the operating Gerik ISR rare earth mine in Malaysia.
The soluble rare earth assemblage is weighted toward magnet rare earth oxides, which account for about 42% of soluble TREO, while neodymium and praseodymium make up about 40% and dysprosium and terbium contribute about 2%.
The mineralisation remains open at depth in every hole intersected, with the deepest samples consistently returning grades above interval averages, which Axel REE reads as evidence of ionic rare earth enrichment toward the base of the saprolite.
Best previously reported auger intercepts included 8m at 597ppm soluble TREO from 6m, 10m at 590ppm from 5m, and 4m at 514ppm from 12m.
Woolrich hosts an inferred mineral resource of 128 million tonnes at 1,013ppm TREO within Axel REE’s broader Caladão resource base of 572Mt at 1,506ppm TREO and 439Mt at 38ppm gallium.
Next Phase Connects Extraction with Product
The immediate program now turns to completing column leach work at Core Resources, finalising the specialist project team and carrying out hydrogeological and geotechnical assessment across the test area.
Axel REE then plans to install the wellfield, begin magnesium sulphate injection, and recover pregnant leach solution for downstream mixed rare earth carbonate production, directly testing the chain from in situ extraction through to a saleable product.
The field trial data will then be integrated with the Caladão Area B mineral resource as Axel REE advances further technical studies around its modular ISR development concept in Brazil.
Non-executive chair Paul Dickson said that Woolrich had consistently demonstrated the hallmarks of a quality ionic clay system and the physical and geological characteristics that favour ISR.
“We are focused on executing this field trial efficiently and systematically, and on building the technical foundation that supports Axel's longer-term ambition to become a producer of high-value MREC products,” he said.
