How Brightstar Resources (ASX:BTR) Is Chasing a Larger Gold Endowment at Two Mile Hill with Deep Extensional Drilling

Sonal Goyal

03 November 2026 10:02 PM AEDT

How Brightstar Resources (ASX:BTR) Is Chasing a Larger Gold Endowment at Two Mile Hill with Deep Extensional Drilling

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Key Highlights

Seven-hole, ~6,500m deep diamond drilling program commenced at Two Mile Hill-Shillington deposit beneath the existing 1.45Moz @ 1.8g/t Au Mineral Resource Estimate
Previous hole TMHDD26003 returned 305m @ 1.33g/t Au from 584m depth, including 173m @ 1.42g/t Au beneath the current resource boundary
The Shirvington Zone tonalite is now confirmed as greater than 400m wide and open at depth, with new holes targeting the undefined western contact
Assays for holes TMHDD26004, TMHDD26005 and TMHDD26006 are due in November, feeding into an updated Mineral Resource and Sandstone Pre-Feasibility Study expected this quarter

Deep Ambitions Below a Proven Resource

Brightstar Resources Limited (ASX:BTR) has moved its exploration agenda underground — quite literally — with the commencement of a seven-hole diamond drilling campaign targeting depths that could materially redefine the size of one of Western Australia's most closely watched gold projects.

The company confirmed on 28 October 2026 that the first of two rigs is now on site at the Two Mile Hill-Shillington deposit, part of the broader 3.6 million-ounce Sandstone Gold Project. A second rig is due to arrive within days, and together they will drill approximately 6,500 metres beneath the existing Mineral Resource Estimate of 24.6Mt @ 1.8g/t Au for 1.45Moz.

The program is focused on the Shirvington Zone, a wide, mineralised tonalite body first intersected by Reverse Circulation Drilling and subsequently confirmed at depth by diamond hole TMHDD26003, which returned 305m @ 1.33g/t Au from 584 metres — including 173m @ 1.42g/t Au below the current resource boundary.

Managing Director Alex Rovira described the significance of that earlier intercept plainly: "Two Mile Hill has the potential to support a larger-scale Mining operation than previously envisaged."

The Geometry Behind the Drill Targets

The current campaign builds on what Brightstar regards as an unusually compelling structural target. The Shirvington Zone tonalite is now confirmed to be greater than 400 metres wide and remains open at depth. New holes are being positioned south of TMHDD26003 and are specifically targeting the undefined western contact of the tonalite — a geological boundary that, if intersected with high-grade mineralisation, could substantially extend the zone's footprint.

The logic behind the positioning is straightforward: earlier RC intercepts and the initial diamond hole have outlined a zone of consistent, wide, relatively high-grade gold mineralisation at depth. The company is now testing whether the Shirvington Zone continues beyond the limits of existing resource modelling.

Assays from holes TMHDD26004, TMHDD26005 and TMHDD26006 are expected in November, and these results — alongside whatever the current campaign yields — are intended to feed directly into an updated Two Mile Hill Mineral Resource Estimate and the Sandstone Pre-Feasibility Study, both of which Brightstar expects to deliver this quarter.

A Project Already Carrying Weight

It is worth noting that Two Mile Hill sits within a larger, multi-deposit system. The Sandstone Gold Project already hosts a total resource base of 3.6 million ounces at 1.4g/t Au, giving the extensional work at Two Mile Hill a platform to potentially elevate the project's overall economic case rather than simply add incremental ounces.

A PFS at this scale is a meaningful development milestone. If the drill results confirm that the Shirvington Zone extends meaningfully at depth, the economic modelling in the PFS could shift substantially in terms of mine plan optionality, resource confidence categories, and potential throughput scenarios.

Risks

Deep diamond drilling programs carry inherent execution risk, including the potential for geological complexity that doesn't match the interpreted model, drilling delays, or assay results that fall short of the grades seen in earlier intercepts. The Two Mile Hill resource currently sits entirely in the Inferred category at depth, meaning any resource upgrade would depend on the quality and density of new drilling data. The Sandstone PFS is also contingent on this updated resource, so delays in assay turnaround or rig availability could push the timeline.

Investors should also note that a PFS outcome, however favourable, does not guarantee the project proceeds to development. Permitting, funding, and market conditions all play a role in determining whether a project advances beyond the study phase.

What to Watch Next

The most immediate datapoint to watch is the November assay release for holes TMHDD26004, TMHDD26005 and TMHDD26006. These results will indicate whether the western contact of the tonalite has been successfully intersected and whether grades are consistent with — or better than — the landmark TMHDD26003 intercept.

Beyond assays, the updated Two Mile Hill Mineral Resource and the Sandstone PFS are the two defining deliverables for the quarter. A resource upgrade that pushes Two Mile Hill above 1.6–1.7 million ounces at maintained grade would signal a project approaching the scale threshold that attracts mid-tier producer interest.

Sector Context

The Australian gold sector continues to benefit from elevated gold prices, which have supported a resurgence in exploration and development activity across Western Australia. Projects with multi-million-ounce potential at meaningful grades are attracting renewed attention from both domestic and international acquirers. Brightstar's dual-rig campaign at depth is consistent with the industry trend of testing the vertical extent of known mineralisation rather than chasing lateral extensions that may require greenfield infrastructure.

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