Great Boulder Resources (ASX: GBR) has intersected exceptionally high-grade gold beneath and adjacent to the existing resource at its Side Well gold project near Meekatharra in Western Australia, with assays returning grades of up to 4,434 grams per tonne gold from deep drilling at the Mulga Bill deposit.
The results come from a diamond drilling program targeting deeper extensions of the Mulga Bill–Eaglehawk system and newly identified zones west of the current resource, highlighting the potential to significantly expand the project’s existing one million ounce gold inventory.
Management says the intersections confirm that high-grade vein systems persist at depth and beyond the current resource boundaries, providing immediate targets for follow-up drilling and future resource growth.
The project sits in the Meekatharra gold field in Western Australia’s Murchison region and lies within trucking distance of several existing processing plants.
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High-Grade Gold Intersected
Great Boulder completed seven diamond holes totalling 3,343 metres between October 2025 and January 2026 to test deep targets beneath Side Well’s Mulga Bill and Eaglehawk deposits.
The program targeted extensions of the intrusive-related gold system that currently hosts a combined Mineral Resource Estimate of 782,000 ounces of gold across the two deposits over a strike length of about 2.5 kilometres.
Drilling delivered several significant intercepts including 1.93m at 574.39g/t gold from 502m.
This contained a spectacular sub-interval of 0.25m grading 4,434g/t gold.
The bonanza zone sits about 430m below surface, an indication that the high-grade vein system continues well beneath previous drilling limits at Mulga Bill.
New Gold Lodes Discovered
The drilling program also intersected new high-grade mineralisation as far as 90m west of the existing Mulga Bill resource in an area that had seen limited previous drilling.
Key results included 0.74m at 48.30g/t gold from 168.6m and 0.54m at 11.70g/t gold from 213.43m.
These intersections are interpreted to represent newly discovered vein-hosted gold lodes with strong intrusive-related gold system pathfinder elements including silver, copper and bismuth.
“These spectacular results highlight the huge scope to continue growing the 1Moz resource at Side Well—the hit of 4434g/t gold 200m below Mulga Bill is particularly exciting given that this resource extends for 2.5km along strike,” managing director Andrew Paterson said.
“Combined with the outstanding hit 90m west of the resource, the implications of these results for the overall resource are clearly significant, [and] we have multiple rigs on site to follow up these results immediately.”
Positioned for Resource Growth
The Side Well gold project currently hosts a MRE of 16.0 million tonnes at 2.0g/t gold for 1.02Moz across several deposits including Mulga Bill, Eaglehawk, Ironbark, and Saltbush.
Mulga Bill remains the largest component with 8.29Mt at 2.4g/t gold for 642,000oz, while Eaglehawk contributes 140,000oz and Ironbark 122,000oz.
Great Boulder plans immediate follow-up drilling to test the newly identified lodes west of Mulga Bill while further diamond drilling will target deeper extensions of the high-grade system.
Additional assays from five remaining deep drill holes are expected in the coming weeks as the company continues exploration aimed at accelerating resource growth across the broader Side Well project.
