Norwest Minerals Limited (ASX: NWM) has commenced drilling to test for ionic adsorption clay (IAC) hosting rare earth elements (REE) at its 1250sq. km Arunta West project in Western Australia.
The 23-hole Air Core drill programme includes the redrilling of three holes that intersected highly enriched REE paleochannel clays in 2015. All high tenor REE clay samples will undergo REE recovery testing to determine if they classify as ionic adsorption clays (IAC).
Norwest is targeting REE in shallow Cenozoic clays thought to be associated with a covered paleo- drainage network.
Although little is known about the REE enrichment of these clays, their geologic setting suggests the REEs were released into solution from the weathering granite parent rock with the soluble REEs migrating tens of kilometres south through the sediment cover package. These REEs attached onto the paleo clay surfaces via ion exchange to form ionic adsorption clays (IAC).
IAC are the most valuable of the REE enriched clays due to their high REE recovery via simple, low -cost processing and minimal reagent (acid) requirements.
Background
In December 2022 Norwest drilled 20 RC holes into a 3km REE soil anomaly located along the contact between the Mount Webb Granites & Bitter Springs sediments.
As all rare earth deposits in the region are hard rock hosted, Norwest targeted the granites along the contact with the three southernmost holes intersecting +1000 ppm TREO in granite saprolite clays. This was the first reported encounter with clay hosted REE in the region.
Subsequently, Norwest undertook a data review of First Quantum Minerals (FQM) 2015 exploration drilling program targeting sediment hosted copper across the Bitter Spring formation.
Although no significant copper was found, FQM’s multi-element assaying revealed strong REE tenor in the near surface clays. The FQM geological report indicates these clays occur within a 40m to 70m thick sedimentary package which includes phanerozoic sandstone, clays and limestone associated with a covered paleo-drainage network.
A total of 24 of the 28 holes were drilled into the cover sequence. The widely spaced drill holes extend across 1000sq. km with assay & XRF results showing:
• Eight intersections > 1000ppm TREO, 5 > 500ppm TREO, and 7 >250ppm TREO.
• high TREO mineralization intersected in Bitter Springs sediments along the entire 90km contact with the local granites.
• high TREO mineralization was intersected up to 15km southwest of the granite-sediment contact
The drill programme is expected to take five to seven days with the REE assay and recovery results reported next quarter.
For further information please visit: https://norwestminerals.com.au/
