Brightstar Resources Ltd
- ASX Code: BTR
- Market Cap: $351,340,031
- Shares On Issue (SOI): 0
Brightstar Resources Drills 305m of Gold at Depth as Hole Ends Without Finding Ore Boundary
Brightstar Resources (ASX: BTR) has reported a 305.4 metre intercept grading 1.82 g/t gold from 351.9 metres depth at its Two Mile Hill-Shillington deposit, part of the 2.9 million ounce Sandstone Gold Project in Western Australia. The Brightstar Resources Two Mile Hill gold drilling results at Sandstone have prompted a significant reassessment of deposit scale, particularly after the drill hole ended in mineralised rock at 657.3 metres — not because the gold-bearing system had been exhausted, but because the rig ran out of drill rods.
That detail is prompting a reassessment of the scale of the deposit among Brightstar's technical team.
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One Hole That Changes the Map
The Two Mile Hill-Shillington deposit currently hosts a Mineral Resource Estimate of 14.6 million tonnes at 1.6 g/t gold for 731,000 ounces, within the broader Sandstone project total of 2.9 million ounces at 1.3 g/t gold. Prior to this drilling round, the eastern contact of the host tonalite intrusion — the rock body interpreted to trap gold mineralisation — was modelled at approximately 60 metres thick at depth.
Drillhole TMHRCD26020 was designed to test that boundary. Instead, according to the company, it passed through the previously expected contact zone and continued intersecting mineralised tonalite to the end of the hole. The intrusion is now interpreted to be greater than 180 metres thick at this location, roughly triple the earlier estimate, with the hole remaining open and accessible for future re-entry.
"These results are potentially game-changing for the Two Mile Hill-Shillington deposit. This new deep drilling could have a material impact on the scale upside of the Two Mile Hill-Shillington deposit. Initial interpretations are that we may be seeing a blow-out of the intrusion to both the east and west at depth, substantially increasing the volume of a prospective host unit," said Alex Rovira, Managing Director of Brightstar Resources.
If confirmed through further drilling, a larger tonalite footprint would suggest a correspondingly larger volume of prospective gold-bearing rock. Additional diamond drilling is scheduled to return to Two Mile Hill in early August, ahead of a planned update to the Mineral Resource Estimate before the end of 2026.
Breaking Down the Key Intercepts
The results cover multiple drillholes across both deep extensional targets and shallower infill positions. The table below summarises the most significant broad intercepts from the diamond tail component of the program.
| Hole ID | From (m) | Interval (m) | Grade (g/t Au) | Gold Content (g-m) | Notes |
|---|---|---|---|---|---|
| TMHRCD26020 | 351.9 | 305.4 | 1.82 | 556 | Ended in mineralised tonalite at 657.3m |
| TMHRCD26009 | 293 | 205.0 | 2.67 | 547 | Infill drilling |
| TMHRCD26007 | 263.5 | 197.7 | 1.14 | 225 | Infill drilling |
| TMHRCD26012 | 206.0 | 116.6 | 1.74 | 203 | Infill drilling |
| TMHRCD26010 | 249.7 | 185.7 | 1.03 | 191 | Infill drilling |
| TMHRCD26005 | 274.0 | 119.0 | 1.55 | 184 | Infill drilling |
These are broad, unconstrained intercepts reflecting bulk mineralisation across the tonalite body. All intervals represent drilled widths; true widths have not yet been confirmed by the company.
Within these bulk envelopes, the deposit displays a pattern of high-grade veins set within a lower-grade but consistently mineralised host rock. Selected high-grade sub-intervals from TMHRCD26020, the deep extensional hole, illustrate this structure clearly.
| Sub-interval | Grade (g/t Au) | Notable Peak |
|---|---|---|
| 17.5m from 351.9m | 9.68 g/t | Includes 1.1m @ 103 g/t Au |
| 13.4m from 531m | 8.59 g/t | – |
| 34.6m from 586.7m | 4.11 g/t | Includes 1.5m @ 46.7 g/t Au at 618.2m |
From the infill program, TMHRCD26009 returned a 15 metre interval at 18.5 g/t gold from 293 metres, including a single one-metre sample at 265 g/t gold. A second interval from the same hole, 2.5 metres at 35.5 g/t gold from 469.3 metres, included 0.8 metres at 107 g/t gold, indicating high-grade shoots persist at depth.
Beyond the tonalite, additional mineralisation was reported in the surrounding basalt and banded iron formation (BIF) sequence, including 2.8 metres at 74.1 g/t gold from 235 metres in TMHRCD26015 and 0.3 metres at 187 g/t gold from 174.6 metres in TMHRCD26010.
Understanding the Geology: What Is a Tonalite Intrusion and Why Does It Matter?
For investors unfamiliar with the terminology, a brief explanation of this host rock helps clarify why these results carry weight.
A tonalite is a light-coloured, silica-rich igneous rock that forms when molten rock intrudes into surrounding rock and solidifies underground. In gold systems such as Two Mile Hill, these intrusions can act as physical and chemical traps for gold-bearing fluids moving through the earth's crust, with gold and quartz veins forming within and around the edges of these bodies.
Because the tonalite at Two Mile Hill hosts mineralisation relatively consistently throughout its volume — rather than being confined to narrow veins alone — a larger intrusion may translate into a larger volume of mineralised material. Tripling the interpreted thickness of the intrusion at depth is therefore presented by the company as a signal that the deposit could be larger than currently modelled, pending further drilling confirmation.
Furthermore, Brightstar's announcement draws comparisons to other Yilgarn gold deposits hosted in similar felsic intrusions, including Thunderbox, Gruyere, Kanowna Belle and King of the Hills.
Key Geological Terms Explained
Glossary of key terms:
- Tonalite: A felsic igneous intrusion that can act as a geological host for gold mineralisation
- MRE (Mineral Resource Estimate): A JORC-compliant estimate of the quantity and grade of gold in a deposit
- RC drilling (Reverse Circulation): A drilling method that brings rock chips to the surface for sampling
- Diamond drilling (DD/RCDT): Drilling that produces a cylindrical core sample for detailed geological study
- g/t Au: Grams of gold per tonne of rock, the standard measure of gold grade
- g-m (gram-metres): A combined measure of interval thickness multiplied by grade, used to compare the relative scale of intercepts
- Indicated Resource: A higher-confidence resource classification that can support mine planning
- PFS (Pre-Feasibility Study): An engineering and economic study assessing whether a deposit can potentially be mined profitably
A Deposit Already Under Study for Underground Mining
The timing of these results is relevant context. Brightstar has appointed engineering firm Entech to complete an underground mining pre-feasibility study at Two Mile Hill. According to the announcement, infill drilling from this program was specifically designed to upgrade portions of the deposit from the lower-confidence Inferred category to the higher-confidence Indicated category, supporting the data density required for mine planning.
That study is proceeding alongside a deposit that, according to the company's revised interpretation, may be larger than the model it was originally based on.
Drillhole TMHRCD26020 ended at 657.3 metres depth in mineralised rock and remains open for potential re-entry, with collar information and gyroscopic survey data retained. Additional diamond drilling planned for early August is intended to help define the full extent of the tonalite and inform a revised resource model.
What Are the Upcoming Milestones?
Key upcoming milestones outlined in the announcement include:
- Diamond rigs returning to Two Mile Hill in early August 2026
- An updated Mineral Resource Estimate incorporating new drilling results, targeted before the end of calendar year 2026
- Continued progress on the underground mining pre-feasibility study with Entech engaged
- Pending assay results for additional holes, including TMHRCD26021 and TMHRCD26022 diamond tails
In addition, four drill rigs — comprising two RC and two diamond rigs — remain active at Sandstone, indicating the drilling program is ongoing.
The Broader Brightstar Platform
The Brightstar Resources Two Mile Hill gold drilling results at Sandstone sit within a company that has been building a considerable resource base across Western Australia. Brightstar's total attributable Mineral Resource base is reported at approximately 4.5 million ounces of gold across the Goldfields and Sandstone regions.
| Region | Total Resources | Grade |
|---|---|---|
| Laverton Hub | ~873,000 oz | 1.7 g/t Au |
| Menzies Hub | ~718,000 oz | 1.5 g/t Au |
| Sandstone Hub | ~2,868,000 oz | 1.3 g/t Au |
| Total (attributable) | ~4,459,000 oz | 1.4 g/t Au |
The Goldfields Hub is progressing toward production. An updated Feasibility Study released in January 2026 outlined production of more than 75,000 ounces per annum for six years, with a life-of-mine cashflow estimated at approximately $1 billion, an NPV8 of $606 million, and an internal rate of return of 74%, according to company disclosures.
Construction of the 1.5 million tonne per annum processing plant is underway, with gold production targeted for the June quarter of calendar year 2027. Sandstone, anchored by Two Mile Hill, represents the next stage of the company's development pathway, and these latest results suggest that stage may extend further than previously modelled.
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Why This Announcement Matters to Investors
Several factors are relevant when assessing the materiality of this result.
The geological outcome favours expansion rather than reduction. The drill intersected more mineralised rock than the existing model anticipated, rather than less.
The host rock comparison references established deposits. Brightstar's announcement draws parallels with Thunderbox, Gruyere, Kanowna Belle and King of the Hills — all recognised gold deposits hosted in similar felsic intrusions.
Visible gold was logged throughout the core. Multiple core photographs referenced in the announcement show gold associated with quartz veins at various depths, including near the end of the hole beyond 600 metres.
A pre-feasibility study is already underway. Entech has been engaged, infill drilling to Indicated confidence is in progress, and the underground mining study is proceeding with these results feeding directly into that work.
A resource estimate update is targeted for this year. With further drilling planned immediately and an MRE update expected before year-end 2026, the market may see how this geological reinterpretation is reflected in reported ounces within a defined timeframe.
The hole remains open. TMHRCD26020 ended in mineralised rock at the practical limit of the drill string, with the eastern boundary of the tonalite yet to be defined.
"Key Takeaway: Brightstar Resources has reported a geologically significant result at Two Mile Hill, distinguished not only by the strength of the assay numbers but by the fact that the drill ended in mineralised rock without locating the boundary it was designed to test. With the tonalite now interpreted as more than three times thicker than previously modelled, a pre-feasibility study in progress, and a resource update targeted before the end of 2026, the coming months at Sandstone represent a period investors in the Western Australian gold sector may wish to monitor."
Want to Know More About Brightstar Resources and the Sandstone Gold Project?
With a drill hole that ended in mineralised rock at 657 metres, a tonalite intrusion now interpreted as more than three times larger than previously modelled, and a pre-feasibility study already underway, Brightstar Resources is presenting investors with a compelling growth narrative ahead of a resource update targeted before year-end 2026. To learn more about the company, its 4.5 million ounce resource base, and the path forward at Two Mile Hill, visit the Brightstar Resources website.
