Core Energy Minerals Reports Yttrium Enrichment at Tunas REE Project

Core Energy Minerals Confirms Depth Potential and Elevated Yttrium at Tunas REE Project

Core Energy Minerals Limited (ASX: CR3) has reported further assay results from the second-phase infill mechanised auger drilling program at its 100%-owned Tunas Rare Earth Element (REE) Project in Paraná, Brazil. Results continue to show thick, near-surface mineralisation and a clear trend of increasing grades with depth. The latest batch also identified yttrium oxide (Y₂O₃) values of up to 637 ppm, marking the first reported significant yttrium enrichment at the project.

The update matters because it adds a new element to the Tunas exploration story. Core Energy confirmed that mineralisation remains open at depth, no fresh basement was intersected, and the strongest part of some holes may not yet have been fully tested due to auger depth limits.

For investors following the rare earths sector, that combination of near-surface scale, favourable magnet rare earth proportions, and rising yttrium values is likely to keep attention focused on upcoming leachability and follow-up drilling results.

What the Latest Tunas Drill Results Show

In the report, Core Energy said the remaining assays from the second-phase infill drilling continue to support a laterally extensive, regolith-hosted REE system across the project area. The company highlighted several intervals from the latest batch of holes.

The strongest single result discussed in the announcement came from TNTR023, where the deepest sample from 13m to 14m returned 2,749.4 ppm TREO and 636.8 ppm Y₂O₃. Core Energy stated the hole ended because of the practical depth limits of the auger method, not because mineralisation had stopped.

That distinction is important. It suggests the weathered profile, which hosts the mineralisation, may continue below the drilled depth and may hold stronger REE and yttrium values deeper in the system.

Managing Director Commentary

"The remaining bulk sample assay results from our second-phase infill auger drilling program continue to reinforce our confidence in the Tunas Project. The latest results have confirmed the lateral continuity of the mineralised horizon and, importantly, continue to demonstrate increasing REE grades towards the base of the weathering profile, with mineralisation remaining open at depth."

— Tony Greenaway, Managing Director, Core Energy Minerals

Why Yttrium Is Important in This Update

The new yttrium data is one of the more material parts of the announcement. While investors often focus first on neodymium and praseodymium in rare earth projects, yttrium is an important heavy rare earth element with industrial uses in advanced ceramics, phosphors, solid oxide fuel cells, and defence-related technologies.

Core Energy said yttrium values at Tunas increase progressively with depth and occur alongside elevated TREO and strong MREO ratios. In practical terms, that means the lower portion of the weathering profile appears to be carrying a more valuable mix of rare earth oxides than the upper section.

Furthermore, rare earth projects are not judged on total grade alone. The mix of contained elements also matters because some rare earths generally command stronger market interest than others. A project with a solid magnet rare earth component and meaningful heavy rare earth content may attract closer scrutiny than one dominated by less sought-after light rare earths.

Core Energy also noted that yttrium is drawing greater attention due to Chinese trade restrictions and its concentrated supply chain. That observation provides market context, however the project-specific significance still depends on future metallurgical and drilling work.

Understanding the Ionic Adsorption Clay Model at Tunas

One of the central themes in this exploration update is Core Energy's view that Tunas may display characteristics associated with an ionic adsorption clay (IAC) rare earth system. An IAC deposit is a style of rare earth mineralisation where rare earth elements are loosely attached to clay particles within deeply weathered rock.

These deposits are commonly sought after because they can, in some cases, be processed using relatively simple leaching methods rather than more complex hard-rock treatment routes.

What Is an Ionic Adsorption Clay Rare Earth Deposit?

For non-specialist investors, IAC deposits represent a distinct and commercially relevant type of rare earth system. Key features of IAC deposits often include:

• Near-surface mineralisation, which may reduce stripping requirements
• Clay-rich weathered material rather than fresh hard rock
• Potential for ion-exchange extraction using conventional reagents such as ammonium sulphate
• A tendency to carry useful proportions of heavy rare earths and magnet rare earths

At Tunas, the mineralisation is hosted within a clay-rich saprolitic horizon developed over weathered biotite gneiss. In simpler terms, saprolite is rock that has been heavily weathered into soft, clay-rich material but still retains some of the original rock texture.

The announcement also described a vertical geochemical pattern in hole TNTR023. According to Core Energy, the upper part of the profile shows elevated cerium values linked to surface weathering, while deeper parts show increasing TREO, MREO, and Y₂O₃. This zonation is presented as being consistent with weathered rare earth systems and supportive of the IAC interpretation.

That said, the company made it clear that the key economic question remains unresolved. The mineralisation model still needs to be validated through leachability work, which is now underway.

Key Technical Terms Investors Should Know

Rare earth announcements often contain dense technical language. The main terms used in this update can be simplified as follows:

This matters because project value in rare earths often depends on more than just one number. Grade, depth, mineral mix, weathering profile, and leach response all play a role in determining commercial viability.

Tunas Project Snapshot

The Tunas project is located in Tunas do Paraná, approximately 75 km from Curitiba and around 162 km from Paranaguá Port. It covers 18.32 km² across two exploration tenements held through Core Energy's wholly owned Brazilian subsidiary Mineração Remo Ltda.

The logistics profile is relevant because early-stage projects located close to existing roads, cities, and port infrastructure often attract more market interest than remote greenfield assets. However, infrastructure alone does not determine project value. The next phase of technical validation remains the primary focus.

What Investors Should Watch Next

The ASX update outlined a clear set of upcoming work programmes, with leachability testwork at the centre of the next round of news flow. The planned and pending work includes:

1. Leachability testwork now underway — Testing whether the mineralisation responds to ion-exchange extraction using conventional reagents such as ammonium sulphate. Positive results would support the IAC interpretation.

2. Sieved sample assay results pending — Samples from holes TNTR025 to TNTR032 are being assessed using both bulk and sieved methods to help refine sampling and analytical procedures.

3. Electric tomography geophysics — This work may be used to define the thickness of the weathering profile across the project area.

4. Reverse circulation drilling subject to results — Pending positive leach test outcomes, Core Energy said follow-up RC drilling may be completed over the main anomalous areas to test below auger depth limits.

Each of these steps serves a different purpose. Leachability addresses processing potential. Sieved sample comparisons refine technical confidence. Geophysics may help define profile thickness, and RC drilling would test whether stronger grades at the base of auger holes continue at greater depth.

Why the Update Matters for the ASX Rare Earths Sector

For ASX investors tracking emerging rare earth projects, the latest Tunas results provide three clear data points. First, the infill programme continues to indicate continuity of near-surface mineralisation across the drilled areas. Second, grades in some holes appear to increase toward the base of the weathering profile, with mineralisation still open where drilling stopped.

Third, the first reported significant yttrium enrichment adds another dimension to the project's rare earth mix. The investment relevance, however, still depends on the next technical steps.

Core Energy has not yet reported leachability outcomes, resource estimates, or development economics for Tunas. As a result, the current announcement is best viewed as an exploration update that strengthens the geological model and sets up near-term technical catalysts.

Investor Takeaway

According to the ASX announcement, Tunas is showing a combination of near-surface REE mineralisation, MREO ratios of up to 38%, and yttrium oxide values of up to 637 ppm, with several holes strengthening at depth. The next key milestone is whether leachability testing supports the proposed ionic adsorption clay model. If that testwork is favourable, the project may move into a more advanced phase of drilling and technical assessment.

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