Alma Metals Hits 383m of Copper at Briggs as Drilling Advances Feasibility Study
Key Takeaways
- Drill hole 26BRD0042 returned 383.8m @ 0.25% Cu from 10.2m depth, including a higher-grade zone of 76.7m @ 0.34% Cu at the geologically predictable intrusive contact on the northern rim of the Briggs deposit.
- The hole ended in mineralisation at its planned termination depth of 394.0m, indicating copper grades extend beyond the current intercept and the system remains open at depth.
- The infill program has now completed approximately 3,600m across ten holes as part of a broader 80-hole campaign targeting 80m drill spacing — the critical step required to convert Inferred Resources to Indicated ahead of a Pre-Feasibility Study.
- At least 200m of strike length has been defined along the northern margin, with further drilling to the northwest planned for later in 2026.
- The Briggs MRE hosts 2 million tonnes of contained copper metal and sits 60km from the deep-water port of Gladstone, Queensland — a tier-one jurisdiction with established infrastructure.
Strong copper returns from Briggs as infill drilling program advances
Alma Metals (ASX: ALM) has received assay results for drill hole 26BRD0042, drilled on the northern side of the Briggs Mineral Resource Estimate (MRE), returning 383.8m @ 0.25% Cu from 10.2m depth, including a standout higher-grade zone of 76.7m @ 0.34% Cu.
The result advances the company’s infill drilling program, which is designed to upgrade Inferred Resources to the Indicated category in preparation for a Pre-Feasibility Study (PFS). The program has now reached approximately 3,600m drilled across ten completed holes, forming part of a broader 80-hole campaign targeting a nominal 80m drill spacing across the entire MRE.
Results are consistent with the geological model and block model expectations, reinforcing confidence in the deposit’s grade continuity and predictability.
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Q1 2026 drill results at a glance
Hole 26BRD0042 ended in mineralisation at its planned termination depth of 394.0m, signalling that copper grades continue beyond the current intercept. The significant assay results are summarised below.
| Interval | From (m) | To (m) | Length (m) | Cu (%) |
|---|---|---|---|---|
| Main intercept | 10.2 | 394.0 | 383.8 | 0.25 |
| Including | 130.0 | 261.0 | 131.0 | 0.31 |
| Including | 146.3 | 223.0 | 76.7 | 0.34 |
| And | 269.0 | 289.0 | 20.0 | 0.31 |
| And | 315.0 | 387.45 | 72.45 | 0.28 |
| Including | 371.0 | 385.0 | 14.0 | 0.38 |
What porphyry copper mineralisation means for investors
A porphyry copper deposit forms when a large body of magma intrudes into surrounding rock. As the intrusive cools, copper-bearing fluids migrate outward, depositing mineralisation in a broadly predictable halo around the intrusive core. It is one of the most common styles of large-scale copper deposit in the world, prized for its size and consistency rather than ultra-high grades.
The contact zone between the intrusive core and the surrounding volcanic or sedimentary rocks is typically where grade concentrates most strongly. At Briggs, the higher-grade zone of 76.7m @ 0.34% Cu occurs precisely at this contact, tracking the boundary between the porphyritic felsic intrusive core and the surrounding volcanosediments in what Managing Director Dr Frazer Tabeart describes as a “consistent and predictable pattern.”
That predictability is what matters most at this stage. Before a PFS can be completed, the geological model needs to be converted from Inferred Resources to Indicated Resources. Inferred Resources carry a lower confidence level, meaning there is insufficient drilling data to define grade and continuity with the precision required for engineering studies. Indicated Resources, by contrast, meet the threshold that allows mine planning and economic analysis to proceed with meaningful confidence.
Converting that resource classification is exactly what this infill program is designed to achieve. Here is why the result from hole 26BRD0042 is material to that objective:
- Consistent mineralisation confirmed along 383.8m of the drill hole from near surface
- Higher-grade zone aligns with the geologically predictable intrusive contact
- Results are consistent with the current MRE block model
- Supports the conversion of Inferred Resources to the Indicated category
At least 200m of strike length has already been defined along this northern margin, and further drilling to the northwest is planned later in 2026.
Director’s confidence in the geological model
Managing Director Dr Frazer Tabeart highlighted the northern rim results as a recurring pattern emerging across the system, reinforcing the geological model that will underpin the PFS.
Dr Frazer Tabeart, Managing Director, Alma Metals
“Hole 26BRD0042 confirms what we are increasingly seeing across the northern rim of the system, a well-developed higher-grade zone of copper mineralisation that follows the contact between the intrusive core and the surrounding volcanics in a consistent and predictable pattern. With at least 200m of strike-length already defined on this margin and further drilling planned to the northwest later this year, we expect to see this zone continue to grow. The predictability of grade distribution here gives us real confidence in the geological model underpinning the Pre-Feasibility Study.”
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Next steps on the path to a Pre-Feasibility Study
The company has outlined a clear sequence of workstreams it is pursuing in parallel with ongoing drilling. For investors tracking progress toward the PFS, the key milestones are:
- Ongoing infill drilling to convert Inferred to Indicated Resources across the first half of the potential mining operation. This program may support an interim MRE update, which in turn could allow for revisions to the Scoping Study.
- Further 35-hole program (approximately 17,500m) in H1 2027 to convert most of the remaining Inferred resource to Indicated. This would provide the basis for an updated MRE to support the engineering, mining, and mine-scheduling components of the PFS.
- Four exploration holes (approximately 1,250m) planned to test surface copper anomalism west of the current MRE boundary.
- Metallurgical test work to optimise copper and molybdenum recovery.
- Evaluation of coarse particle flotation and the potential addition of a molybdenum circuit to the mineral processing flowsheet to maximise potential copper and molybdenum revenue streams.
- Environmental baseline surveys, with consultants appointed and further specialist engagements planned.
The Briggs project hosts a Mineral Resource Estimate containing 2 million tonnes of copper metal in Indicated and Inferred Resources at a 0.15% Cu cut-off grade. The project is located 60km from the deep-water port of Gladstone, Queensland, in a tier-one jurisdiction with substantial existing infrastructure supporting its development economics.
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