Lynas Rare Earths Limited announced the results of a 1 kilometre deep exploration hole drilled in fresh carbonatite below the current Mt Weld life of mine design and ore reserve. The results confirm continuous Rare Earth Element mineralisation along the 1020m drill core at an average grade of 2.22% REO, no cut-off grade applied. Apatite Zones at shallower depths show enriched REE grade.

The successful completion of the 1 km deep diamond drill hole was announced on 2 August 2021. The drilling program was partially funded by the Western Australia Government Exploration Incentive Scheme. The Mt Weld Carbonatite is a sub-vertical cylindrical igneous intrusion approximately 3.6 kilometres in diameter.

The MWC is concealed under a 25m thick layer of younger transported alluvial sedimentary cover. Prior to the sedimentation, a prolonged widespread lateritic weathering process over the Laverton geological region has concentrated REE minerals in the carbonatite's upper saprolite zone. The saprolite zone has variable thickness from about 80m to 120m below the surface.

Lynas' current REE open pit mine is about 65m deep and is producing REE ore from the saprolite zone. Previous exploration activities focused on the saprolite zone and shallow depths of less than 150m. The drilling of MWEX10270 was carried out to obtain a better understanding of the mineralogy and REE mineralisation within the fresh carbonatite below the Mineral Resource.

Analysis of samples obtained from the exploration drill hole have revealed: REE mineralisation was confirmed along the entire 1010m drillhole at an average grade of 2.22% REO, no cut-off grade applied. The weathering process has significantly enriched the REE grade in the saprolite zone, due to the relative enrichment of monazite within the Apatite Zones. Apatite Zones at shallower depths show 27m of 7.6% REO and 23m of 13.67% REO.

All samples returned REE assay; the highest grade is 21.44% REO from 60m to 62.4m hosted in the apatite zone and the lowest grade is 0.17% REO in a 4m composite sample from 969m to 973m depth hosted in calcite-rich carbonatite. The REE mineralisation continued beyond the end of the drillhole, with the last 4 meters of single metre samples analysed at an average grade of 1.47% REO from 1016m to 1020m.Dolerite dyke emplacement has resulted in a metasomatic alteration /remelting zone in carbonatite from 600m to 800m depth, which has been identified in the MWC as favourable for relative enrichment of HREE. Significant REE mineralisation observed is hosted within the dolomite and ankerite carbonatites of the upper 800m of the drill core.

The results reveal a large area of new exploration target in the fresh carbonatite below the zone of surficial aweathering profile.