Brightstar’s Bull Oak drilling adds broad gold zones ahead of resource upgrade

Brightstar Resources Limited (ASX:BTR) has ended its latest Bull Oak drilling program with a result that is broad enough to matter beyond the headline grade: 167 metres at 2.07g/t gold from 104 metres. The intercept sits alongside narrower, much higher-grade zones, including 0.5 metres at 265g/t within 14.5 metres at 10.8g/t in diamond hole BODD26010.

Broad mineralisation anchors Bull Oak drilling results

Other bulk intervals included 124 metres at 1.45g/t from 147 metres and 75 metres at 1.78g/t from 247 metres. Within the granodiorite host, Brightstar also reported 10 metres at 25.0g/t, including 1 metre at 242g/t; 14 metres at 9.13g/t, including 1 metre at 113g/t; and 42 metres at 2.91g/t, including 1 metre at 60.7g/t.

The results are not confined to the intrusive unit. Drilling in the neighbouring basalt and banded iron formation sequence returned 7 metres at 9.77g/t from 40 metres, including 1 metre at 61.8g/t, while separate diamond holes produced 8 metres at 3.83g/t and 0.5 metres at 42.7g/t. These are downhole intersections; Brightstar says true widths have not yet been confirmed.

Resource upgrade is the immediate test

Bull Oak currently contains 10.5 million tonnes at 1.0g/t gold for 322,000 ounces, with most of the mineralisation hosted by a shallowly east-dipping vein system within granodiorite. The latest program comprised 39 reverse-circulation holes for about 7,500 metres and 11 diamond holes for roughly 2,900 metres, aimed at moving a significant portion of the resource from Inferred to Indicated classification.

That classification change is the practical significance of the announcement. Brightstar says the diamond core will also provide structural, geotechnical and metallurgical information for the Sandstone pre-feasibility study. The company is assessing Bull Oak as a potential open-pit ore source, but the drilling results alone do not establish mineability, reserves or project economics.

Sandstone study moves towards its next milestones

Brightstar says the Bull Oak results will be incorporated into the next resource update, which is expected to increase the Indicated component ahead of the Sandstone PFS targeted for release before the end of 2026. Mineralisation remains open at depth, including in one of the deepest Bull Oak holes, leaving room for further resource growth but also extending the amount of work needed before the deposit can be defined with greater confidence.

Three rigs remain active across the broader portfolio. The RC rig has moved from PFS drilling to early-stage Sandstone targets, while the diamond rig is being mobilised to Menzies to test depth extensions at Yunndaga and Lady Shenton. Two diamond rigs are also targeted for Two Mile Hill later in October, with drilling focused on the deeper Shirvington Zone. The next meaningful read-through for Bull Oak will be whether these impressive intercepts translate into a larger, better-classified resource and then survive the economic and metallurgical filters of the PFS.