- 01305m at 1.33g/t gold below Two Mile Hill resource.
- 02Includes 173m at 1.42g/t, to 770m depth.
- 036,500m drilling planned; three assays pending.
Brightstar Resources (ASX: BTR) has intersected gold mineralisation well below the existing Two Mile Hill-Shillington resource at its Sandstone gold project in Western Australia, opening another avenue for resource growth.
The first assay result from a four-hole deep drilling campaign returned a mineralised interval of 305 metres grading 1.33 grams per tonne gold, beginning 584m downhole within the host tonalite.
Crucially, that broad intersection contained 173m at 1.42g/t gold from 716m beneath the current mineral resource estimate, confirming mineralisation beyond the boundary used in the latest model.
The result comes as Brightstar prepares another 6,500m of drilling to test the extent of the Shirvington Zone while assays from the remaining three deep holes are pending.
Deeper Resource Opportunity
The Two Mile Hill-Shillington deposit currently contains 24.6 million tonnes grading 1.8g/t gold for 1.45 million ounces, within the wider Sandstone project resource of 3.6 million ounces.
While its September MRE showed contained gold increasing with depth to a peak around 595m vertically below surface, the latest mineralised interval extends from approximately 620m to 770m vertical depth.
That relationship is central to the result, because the drilling crossed the established resource envelope rather than merely adding another intersection inside an already modelled zone.
Gold mineralisation occurs predominantly in a tonalite intrusion, where the Shirvington Zone widens at depth and where the company is assessing the scope for a bulk underground operation.
Although the drilling has pushed the known tonalite width beyond 400m, the four holes did not reach its western contact, leaving the full extent of the host rock unresolved.
Grades within Broad Zone
The 305m bulk result includes higher-grade portions, notably 28m at 1.95g/t gold from 713m and 6m at 11.2g/t from 765m, showing variation within the mineralised tonalite.
Elsewhere in the same hole, separate tonalite-hosted intervals included 6.7m at 5.13g/t from 484m, while mineralisation was also intersected in adjacent basalt and banded iron formation.
Brightstar now calculates broad tonalite intercepts using a 0.25g/t cut-off, allowing up to 5m of consecutive internal dilution and requiring an overall grade of at least 0.5g/t.
These are downhole intercept lengths rather than confirmed true widths, and assays from only the southernmost hole of the deep campaign have been received so far.
Multi-Rig Program Set
“The first hole from the deep Two Mile Hill drilling program has produced an excellent result, meeting our expectations and delivering a broad, 300m-plus downhole zone of gold mineralisation,” managing director Alex Rovira said.
“The planned multi-rig ~6,500m program is scheduled to commence this month, targeting southern extensions of the Shirvington Zone, further confirming mineralisation at depth and defining the western tonalite contact to better constrain the extent of this prospective host unit.”
Information from that work and the three outstanding deep-hole assays is intended to feed into another resource model update, with the proposed underground opportunity being considered alongside potential open pit mines.
In parallel, Brightstar is progressing targets across the neighbouring felsic intrusions between Two Mile Hill and Bull Oak, with initial tests targeted for the December quarter.
“We aim to test a number of these targets in the current December quarter, ahead of a more substantial drilling program across the corridor in early 2027,” Mr Rovira added.
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