Oceana Metals Doubles Serra Negra REE Footprint to 4.5 sq km Without New Drilling
Key Takeaways
- Re-sampling of historical phosphate drill core has more than doubled the known REE mineralisation footprint at Serra Negra to 4.5 sq km within a 10km-diameter carbonatite complex — without drilling a single new hole across the broader project area.
- Three headline intercepts from the latest batch include 106m @ 1.00% TREO from 18.9m (OA167) and a peak assay of 10.59% TREO with 6.39% Nb₂O₅ from hole LG31, signalling both scale and a second niobium value driver.
- Assays from 45 historical holes (~4,750m) remain pending, meaning the current 4.5 sq km mineralised footprint is expected to grow further before maiden drilling results are even released.
- The re-sampling programme has saved approximately A$2.5 million in equivalent drilling costs, with all 68 available historical holes now re-sampled using modern lithium borate fusion ICP-MS methods.
- Oceana is well-funded with approximately A$8.16m cash at 30 June 2026 plus a further A$12.6 million received from Tranche 2 of its Placement in July 2026, providing a strong runway into first maiden drilling assays expected early Q4 2026.
Serra Negra doubles in size as re-sampling uncovers major new REE zone
Re-assaying historical drill core that was never designed to target rare earths has doubled the known area of REE mineralisation at Serra Negra to more than 4.5 sq km within the carbonatite complex — a significant exploration breakthrough achieved without a single new drill hole across the broader project area.
Oceana Metals Limited (ASX: OCN) holds the Serra Negra Project in Minas Gerais, Brazil, where previous operators drilled for phosphate rather than rare earth elements or niobium. The company is now extracting substantial new geological understanding from that existing core using modern analytical methods, while simultaneously running a maiden drilling programme with two rigs in the priority Central area. First assay results from that programme are expected in early Q4 2026 (calendar).
Managing Director Mick Wilson
“These latest assays from historic core provide more evidence that Serra Negra is rapidly emerging as a major rare earths project.”
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Q1 FY27 (September 2026) exploration highlights
Key results from the latest re-sampling programme include:
- Known REE mineralisation footprint more than doubled to 4.5 sq km within the 10km-diameter carbonatite complex
- New thick REE intervals from wide-spaced historical holes (300m–1km apart):
- 32m @ 2.7% TREO within 122m @ 1.2% TREO from 50m (L179) — Peak Assays: 4.79% TREO, 1.19% MREO
- 106m @ 1.00% TREO from 18.9m (OA167) — Peak Assays: 4.34% TREO, 1.01% MREO
- 26m @ 1.4% TREO + 0.63% Nb₂O₅ from 127m to EOH (LG31) — Peak Assays: 10.59% TREO, 2.22% MREO, 6.39% Nb₂O₅
- All 68 available historical drillholes have now been re-sampled; assays still pending from 45 holes (~4,750m)
- High-resolution drone magnetic survey completed across the priority target area; inversion modelling underway
- Company well-funded: approximately A$8.16m cash as at 30 June 2026, plus a further A$12.6 million (before costs) received from Tranche 2 of the Placement in July 2026
How re-sampling historical core is creating district-scale value
A cost-effective shortcut to regional understanding
Rather than drilling entirely new holes across a 10km carbonatite complex, Oceana is systematically re-assaying historical drill core using modern analytical methods for the full REE suite and co-products such as niobium. The previous operators drilled these holes to test for phosphate — not rare earths — which makes positive intercepts across the full breadth of the complex particularly significant for understanding scale.
Managing Director Mick Wilson highlighted the economics of the approach: the re-sampling programme has saved approximately ~A$2.5 million in equivalent drilling costs, plus the time that would have been required to complete an equivalent new programme.
The process works as follows:
- Collection — Quarter core samples taken at 1m intervals from available historical core, respecting geological contacts
- Analysis — Samples dispatched to ALS Belo Horizonte for the full suite of REE and niobium assays using lithium borate fusion ICP-MS
- Integration — Results fed into Oceana’s evolving geological model of the Serra Negra Carbonatite Complex
- Target refinement — Assay data, combined with drone magnetic and LiDAR datasets, guides targeting for the maiden Oceana-led drilling programme
Because holes were drilled at 300m–1km spacing and were never intended to test for REE, each new batch of assays is meaningfully expanding the company’s understanding of mineralisation scale and continuity.
Niobium adds a second value driver
Recent re-sampling results are also highlighting significant niobium mineralisation across parts of the project, reinforcing the broader prospectivity of the Serra Negra system. The LG31 intercept — 26m @ 1.4% TREO + 0.63% Nb₂O₅ from 127m — is a notable example of both REE and niobium occurring coincidentally in a wide-spaced hole that was never designed to test for either element.
Managing Director Mick Wilson
“The presence of both rare earths and evidence of coincident niobium mineralisation in wide-spaced holes…highlights the fertility of the Serra Negra carbonatite system and provides an additional avenue for value creation as Oceana’s exploration advances.”
What makes carbonatite rare earth systems so compelling?
Carbonatites are igneous rocks unusually enriched in carbonate minerals, formed by rare magmatic processes. They are one of the highest-grade rare earth element (REE) host rock types known to geologists, and Serra Negra’s weathered carbonatite setting places it in the same broad geological style as some of the world’s largest and highest-grade REE deposits — including Mount Weld in Western Australia, referenced explicitly in the announcement.
The “hard rock” carbonatite setting is regarded by explorers and investors as favourable for both scale and grade potential.
Two key metrics appear throughout Oceana’s reporting:
- TREO (Total Rare Earth Oxides) — the sum of all rare earth oxide values, reported as a percentage. This is the broadest measure of REE content.
- MREO (Magnet Rare Earth Oxides) — specifically Nd₂O₃ + Pr₆O₁₁, the rare earths most in demand for electric vehicle motors and wind turbines. A high MREO fraction within TREO is commercially significant.
The three headline intercepts from this release, compared side by side:
| Hole ID | Interval (downhole) | TREO Grade | MREO Grade |
|---|---|---|---|
| L179 | 32m within 122m from 50m | 4.79% TREO (peak) | 1.19% MREO (peak) |
| OA167 | 106m from 18.9m | 4.34% TREO (peak) | 1.01% MREO (peak) |
| LG31 | 26m from 127m to EOH | 10.59% TREO (peak) | 2.22% MREO (peak) |
The LG31 intercept is particularly notable for its peak niobium grade of 6.39% Nb₂O₅, a co-product that adds a second prospectivity signal within the same system.
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What’s next — milestones and investment thesis
Indicative timetable
The company’s indicative timetable for key upcoming milestones is as follows (noting this timetable is indicative only and is subject to change, as stated in the announcement):
- Historical core re-sampling assay results — Ongoing
- Interpretation of drone magnetic and LiDAR datasets — September 2026
- First assay results from maiden Oceana-led drilling programme — Early Q4 2026 (calendar)
- Introduction of additional rigs and expansion of drilling capacity — Early Q4 2026 (calendar)
- Maiden Mineral Resource Estimate for Serra Negra — Coming months
The investment case
Serra Negra is emerging as a potentially district-scale REE system being defined at low cost through the re-sampling of historical core. With 45 holes (~4,750m) still to return assay results, the current 4.5 sq km mineralised footprint is expected by the company to continue growing. Assays from wide-spaced holes in a carbonatite setting are also informing drill targets for the live maiden programme, which is already testing the 1.5km x 1.5km priority Central area — host to existing intercepts of up to 50m @ 4% TREO.
The Serra Negra drilling program was launched with a 20,000m target across the priority Central area, where existing intercepts of up to 50m at 4% TREO have already outlined a high-grade core for systematic testing.
On the corporate side, completion of the acquisition of Songeo Mineração S.A. is expected imminently, with both parties working on satisfying the remaining conditions precedent.
The company remains well-funded, with approximately A$8.16m cash as at 30 June 2026 and a further A$12.6 million (before costs) received from Tranche 2 of the Placement in July 2026.
As Managing Director Mick Wilson put it, Serra Negra offers “multiple opportunities for value creation through expansion of the known system and discovery of additional mineralised centres.”
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