Heavy Rare Earths Limited (“HRE” or “the Company”) is pleased to announce its December 2022 quarterly activities report for the second quarter since listing on the Australian Securities Exchange (ASX).
- 438-hole rare earth exploration and resource expansion drilling program at Cowalinya complete with thick sequences of clay-rich saprolite intersected across the project area
- Assays from initial 53 holes deliver coherent zones of rare earth mineralisation
- Total rare earth assays of up to 2255 ppm TREO returned
- Particle size (metallurgical) analysis reveals up to 90% of rare earths hosted in -25 µm size fraction in as low as 21% of bulk saprolite feed
- Rare earth grade increase of up to 299% in -25 µm size fraction
- Re-assaying of samples from 2021 Cowalinya resource drilling delivers an average increase of 3.8% in total rare earths
- Acquisition of additional exploration tenements in the Cowalinya project
- Well-funded to progress with company objectives and exploration activities
HRE’s key exploration project is Cowalinya in the Norseman-Esperance region of Western Australia. This is a clay-hosted rare earth project with a JORC Inferred Resource of 28 Mt @ 625 ppm TREO1 and a desirable rare earth composition where 25% are the valuable magnet rare earths and 23% the strategic heavy rare earths.
Cowalinya Rare Earth Project, Western Australia
Analytical (Re-Assay) Program
During the quarter the Company announced results from 729 two-metre composites from 102 air core holes drilled at Cowalinya in 2021 which were re-assayed by Lithium Borate Fusion/ICP-MS (refer to ASX announcements 4 and 26 October 2022).
The program delivered a length-weighted average grade in total rare earth oxides (“TREO”) of 856 ppm for samples where the original analytical work by 4-Acid Digest/ICP-MS (on largely four-metre composites) returned assays above 300 ppm TREO-CeO2, the cut-off grade for the project’s Inferred Mineral Resources.
This represents a 3.8% increase in grade over the original assays which average 825 ppm in contrast to the more modest resource grade of 625 ppm that includes significant dilution in the grade estimate.
The results from the Analytical (Re-Assay) Program confirm routine two-metre sample compositing for assay by Lithium Borate Fusion/ICP-MS as the basis for future grade estimation of rare earth mineralisation from the Company’s ongoing resource exploration and expansion program at Cowalinya.
Resource Exploration and Expansion Drilling Program
During the quarter the Company completed its 438-hole resource exploration and expansion drilling program at Cowalinya, and announced assays from the first 53, or 12%, of the holes (refer to ASX announcement 1 December 2022).
These 53 vertical air core holes, drilled on 200 metre centres to depths of between 7 and 52 metres, were amongst the first 92 holes drilled in the current program along five north-south and east-west lines up to 4.2 kilometres long. These drill lines were designed to explore for thick developments of clay-rich mineralised saprolite on the Company’s E63/1972 tenement primarily to the south and south-east, but also immediately east and west, of the Cowalinya South rare earth deposit, and be used to guide subsequent grid-based resource expansion drilling. Their locations were determined using a combination of publicly available airborne electromagnetic and magnetic, and digital elevation model data.
Drilling by HRE successfully intersected saprolite along all five exploration drill traverses. Saprolite averages 17.1 metres thick along these traverses which compares with 17.7 metres for the Cowalinya resource. In the subsequent 207 air core holes which were drilled on 200 x 400 metre centres mainly to the west and south of the Cowalinya South resource, the average thickness of saprolite increases by 29.8% to 22.2 metres.
Subsequent to the end of the quarter, the Company announced assays from the remaining 39 air core holes along the five exploration traverses (refer to ASX announcement 3 January 2023). These assays, when combined with those from the first 53 holes, demonstrate that coherent zones of saprolite-hosted rare earth mineralisation are apparent up to 4.2 kilometres away from the Cowalinya South deposit. The widest of these mineralised zones, defined by 11 consecutive 200 metre-spaced holes located west of the deposit along drill section A-B on Figure 1, now exceeds 2 kilometres, with mineralisation open to the west of hole AC201. A second zone of mineralisation at least 600 metres wide is present on the same drill section and possibly represents part of an easterly/south-easterly extension to the Cowalinya South resource2. Confirmation of this extension awaits assays from a number of holes north and south of AC178-AC181 and east of AC110-AC112.
Table 1 lists rare earth assays for all mineralised intercepts in the 92 reported holes (AC110- 181, AC186-205) where their grade-thickness exceeds the average grade-thickness of the mineralised horizon in the Cowalinya deposit (~9 metres thick @ 624 ppm TREO3).
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Table 1: Summary of financial metricsExchange Rates used, 1 
Figure 1 – ChemX HiPurA® Solvent Extraction (SX) module completed, pending energisation infrastructure installation
Figure 1: Location of the Gyttorp property (red cross), with new properties within the black square.