Great Boulder Resources has intersected coarse visible gold in its first deep diamond drill hole at the Mulga Bill prospect, confirming the large-scale potential of the Side Well Gold Project’s key gold system. Assay results are expected in January 2026.
- First deep diamond drill hole at Mulga Bill intersects coarse visible gold
- Drilling extends approximately 200m below previous programs
- Confirms large-scale potential of 3km-long Mulga Bill – Eaglehawk gold system
- Preliminary assay results anticipated in January 2026
- Ongoing drilling with three rigs and resource update planned for December 2025
Visible Gold Breakthrough at Depth
Great Boulder Resources has announced a significant milestone in its exploration campaign at the Side Well Gold Project in Western Australia. The company’s first deep diamond drill hole at the Mulga Bill prospect, designated 25MBRCD002A, has intersected coarse visible gold within a brecciated quartz vein zone at a depth of approximately 503.5 metres. This intersection lies about 200 metres beneath the deepest previous drilling, marking a substantial step-out that confirms the large-scale potential of the Mulga Bill – Eaglehawk gold system.
Geological Context and Significance
The visible gold was found hosted within a silica-sericite altered zone featuring disseminated and stringer pyrite mineralisation. This vein-hosted gold occurrence aligns with the company’s hypothesis of a large, intrusive-related gold system extending over a strike length of more than 3 kilometres. While visual identification of gold is an encouraging indicator, Great Boulder cautions that such observations are not a reliable proxy for grade or economic value, pending laboratory assay confirmation.
Ongoing Drilling and Resource Development
Drilling continues robustly at Side Well, with three rigs operating until the Christmas break. The company is advancing multiple targets, including extensional drilling at the Flagpole prospect south of Mulga Bill. Great Boulder is on track to deliver an updated Mineral Resource Estimate (MRE) for the project by the end of 2025, encompassing deposits such as Mulga Bill, Eaglehawk, Ironbark, Saltbush, and Golden Bracelet. The current MRE stands at 668,000 ounces of gold at an average grade of 2.8 grams per tonne.
Strategic Positioning and Support
The Side Well project is strategically located in the prolific Meekatharra gold field, adjacent to established operations like Westgold Resources’ Paddy’s Flat. The project benefits from strong infrastructure and government co-funding, with Great Boulder securing $180,000 in exploration incentives from the Western Australian government to support its drilling program. Managing Director Andrew Paterson highlighted the significance of the deep visible gold intersection, describing it as a “bonanza zone” structure and a clear sign that the company is only beginning to unlock the system’s potential.
Looking Ahead
Preliminary assay results from the deep drilling are expected in January 2026, which will provide critical data to validate the visual gold findings and inform the upcoming resource update. The company’s methodical approach, combining detailed geological logging, multi-rig drilling, and rigorous sampling protocols, positions Great Boulder well to advance the Side Well project towards development. Investors and analysts will be watching closely for assay outcomes and the impact on the project’s resource base.
Bottom Line?
Great Boulder’s deep drilling breakthrough at Mulga Bill sets the stage for a potentially transformative resource update early next year.
Questions in the middle?
- What will the January 2026 assay results reveal about the grade and economic viability of the visible gold zone?
- How might the new deep drilling data influence the upcoming Mineral Resource Estimate for Side Well?
- Could the discovery of ‘bonanza zone’ structures at depth lead to a reassessment of the project’s overall scale and development timeline?