Great Boulder Resources (ASX:GBR) deep drilling extends Side Well growth path while testing resource depth
February 11, 2026Andrew Paterson, Managing Director of Great Boulder Resources, joins MarketOpen today to discuss the latest price sensitive drilling update from the Side Well Gold Project in Western Australia, where recent diamond and air core programs have returned high grade results below and along strike of existing deposits and are being used to guide mine planning, resource growth and sequencing of next stage work.
What specifically has the latest drilling confirmed below the existing Ironbark resource and why was this program undertaken?
The recent diamond program at Ironbark was primarily designed to collect geotechnical and metallurgical information for open pit mine planning, while also targeting the resource position wherever practical, and several holes intersected high grade mineralisation below the current resource envelope.
We reported 15.32m at 8.85g per tonne gold from 125.38m and 1.08m at 9.16g per tonne gold from 179.24m, with the latter representing the deepest high grade intersection recorded at Ironbark to date.
This was an area where we thought mineralisation was pinching out, so the new high-grade result below that level is an indication that the lode may continue at depth – representing a potential target for underground mining.
These results demonstrate continuity of high grades at depth beneath the existing 122,000 ounce Ironbark resource and directly support further targeted drilling below the current model.
How do the Ironbark results fit alongside the previously reported deep intersection at Mulga Bill?
The Ironbark outcomes follow our December deep diamond result at Mulga Bill, where hole 25MBRCD002A intersected coarse gold in a quartz vein at approximately 503.52m to 503.77m downhole and that core is still being processed with assays pending.
Together, these two areas show that mineralisation is present well below the levels currently captured in parts of the Side Well resource base and that depth extensions are a repeatable exploration theme rather than an isolated outcome.
The Mulga Bill deep hole is being cut and sampled with laboratory results expected within weeks, and drilling there continues under an EIS co funded program.
The presence of mineralisation at these deeper levels across multiple deposits strengthens our confidence that growth potential is not restricted to near surface positions.
What did the Flagpole drilling deliver and how does that affect the resource growth profile across the corridor?
Air core drilling at Flagpole, which sits about 3km south of Mulga Bill at the southern end of the 6km Central Corridor, returned several high grade intercepts both within and north of the current resource area.
Reported highlights include 4m at 16.55g per tonne gold from 64m, 15m at 2.20g per tonne gold from 94m including 5m at 4.19g per tonne gold, and 16m at 1.51g per tonne gold from 88m. These results confirm additional higher grade zones and support the interpreted lode orientations, while also showing that mineralisation remains open along strike and at depth.
Drilling in early 2026 has continued to define the northern extent of the deposit, and this ongoing step out and extensional work is directly aimed at expanding the Flagpole resource footprint.
How is the company sequencing drilling and field activity across Side Well following this update?
Drilling is continuing with multiple rigs targeting extensional mineralisation at both Flagpole and Mulga Bill, while diamond drilling programs are also supporting geotechnical and metallurgical datasets needed for mine planning inputs.
We currently have three rigs operating at Side Well and approximately $15m in cash, which allows us to run parallel programs across several deposits rather than progressing targets one at a time.
A dedicated core yard has been established in Meekatharra to process the backlog of diamond core from Mulga Bill and Eaglehawk, which improves sample handling and turnaround efficiency.
Running concurrent drilling and core processing streams reduces operational bottlenecks and supports more regular technical updates as results are received.
Beyond drilling, what parallel workstreams are underway that influence development timing and optionality?
Alongside drilling and technical studies, we are continuing discussions with the Yugunga Nya mining agreement negotiation committee during February with the aim of advancing toward a conclusion as quickly as possible.
That process sits alongside the technical work programs and is part of preparing the project for future development pathways. The Side Well Project currently hosts a Mineral Resource Estimate of 16.0Mt at 2.0g per tonne gold for 1.02Moz, with open pit and underground components reported across multiple deposits and constrained by defined cut off grades and depth limits.
Maintaining progress across agreements, resource definition and mine planning inputs in parallel increases our practical development flexibility as the dataset grows.
Development Pathways Framed by Depth Growth and Processing Options
In practice, the Side Well strategy is built around expanding mineralisation at depth and along strike across multiple deposits while collecting geotechnical, metallurgical and planning data that supports future mine design decisions, with Great Boulder Resources Managing Director Andrew Paterson positioning the program to grow the resource base and preserve flexibility between a stand alone development pathway or supplying one of three nearby mills within trucking distance
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