Great Boulder Resources Achieves 1 Million Ounce Gold Resource Milestone

Great Boulder Achieves Major Milestone with 1+ Million Ounce Gold Resource

Great Boulder Resources has reached a significant milestone in its exploration journey, announcing an updated Mineral Resource Estimate (MRE) that positions its Side Well Gold Project as a substantial gold asset in Western Australia's proven Murchison region. The Great Boulder Resources 1 million ounce gold resource establishes the company as a significant player in the Western Australian gold sector.

Updated Resource Delivers Strong Growth

The company's latest resource update reveals impressive scale and quality metrics that underscore the project's development potential:

Furthermore, the key highlights include 61% of ounces now classified in the higher confidence Indicated category. Additionally, approximately 90% of ounces are suitable for open pit mining.

Moreover, the high-grade core at Mulga Bill contains 441,000oz @ 5.3g/t Au. The development also showcases a multi-deposit portfolio across six defined resources.

"When we first started drilling at Side Well, we quickly realised the project had genuine multi-million-ounce potential and we are very pleased to deliver on the first 1Moz milestone as we continue to aggressively drill and deliver further resource growth and additional discoveries," commented Managing Director Andrew Paterson.

This achievement demonstrates substantial scope for further expansion across multiple exploration corridors, reinforcing the Great Boulder Resources 1 million ounce gold resource significance.

Mulga Bill Emerges as Flagship Deposit

The Mulga Bill deposit has evolved into the project's cornerstone asset, demonstrating both substantial scale and high-grade characteristics that position it favourably for development. In addition, this deposit represents the strongest component of the overall resource portfolio.

Mulga Bill Resource Breakdown:

The deposit's 77% Indicated classification reflects significant drilling density and geological confidence. However, recent deep drilling has revealed visible gold mineralisation 200m below previous drilling, indicating substantial expansion potential.

Recent drilling highlights include:

• Extension of mineralisation 300m north towards Eaglehawk
• Confirmation of the multi-kilometre gold system through diamond drilling
• High-grade component: 441,000oz averaging 5.3g/t Au

Multiple Growth Vectors Across Six Deposits

The Side Well project demonstrates district-scale potential through its diversified deposit portfolio. For instance, each deposit offers distinct expansion opportunities that contribute to the Great Boulder Resources 1 million ounce gold resource.

Eaglehawk: The Emerging Giant

The Eaglehawk deposit represents exceptional growth potential with its current resource of 140,000oz and a maiden estimate completed. Furthermore, the strike potential extends 1.5km identified, with 800m currently defined.

Additionally, a recent intersection of 105m @ 2.41g/t Au (post-resource cutoff) demonstrates continued mineralisation. The expansion upside suggests similar geological setting to Mulga Bill, indicating comparable scale potential.

Ironbark: Advanced Development Candidate

Ironbark presents an established resource of 122,000oz with 81% in Indicated category. Moreover, a scoping study completed in July 2025 outlined the development pathway.

Metallurgical testing includes diamond drilling samples being processed for comminution and bond work index. The strategic location positions the deposit within an established mining infrastructure corridor.

Growth Stage Deposits

Flagpole, Saltbush, and Golden Bracelet represent early-stage discoveries with significant expansion potential:

What Makes Open Pit Resources More Valuable?

Open pit resources represent mineralisation within 200m of surface (150m for smaller deposits). In contrast, these deposits can be extracted using conventional mining equipment with lower operating costs and higher production rates.

Underground resources below these depths require different extraction methods. However, they often host higher-grade mineralisation, as demonstrated by Mulga Bill's underground component averaging 5.5g/t Au.

This distribution is particularly attractive to investors as approximately 90% of Side Well's resources suit lower-cost open pit extraction. Nevertheless, underground zones provide high-grade optionality for extended mine life.

Such flexibility enhances the economic potential of the Great Boulder Resources 1 million ounce gold resource. Furthermore, mining companies typically prefer projects where the majority of resources can be extracted through open pit methods.

These operations generally require lower capital investment and operating costs compared to underground mining. Additionally, the ability to access high-grade underground zones later provides additional value and extends operational timeframes.

2025: A Year of Discovery and Growth

The company delivered exceptional exploration results throughout 2025, systematically advancing multiple fronts. Consequently, these efforts built toward achieving the milestone of over one million ounces of gold resources.

New Discoveries:

• Four maiden resources established: Eaglehawk, Flagpole, Saltbush, and Golden Bracelet
• Resource growth at established Mulga Bill and Ironbark deposits
• Deep discovery at Mulga Bill confirming system-scale potential

Resource Confidence Improvements:

• Significant upgrading from Inferred to Indicated categories
• 61% of total ounces now in higher confidence Indicated classification
• Systematic infill drilling validates geological interpretations

The progression from exploration targets to defined resources demonstrates the company's methodical approach to resource development. For instance, each new discovery adds not only to the total resource inventory but also validates the geological model across the broader district.

Strategic Positioning and Development Timeline

Great Boulder's Side Well project benefits from strategic location advantages that support development economics. In addition, the project's positioning in the proven Murchison region provides significant infrastructure benefits.

Infrastructure Advantages:

• Heart of Meekatharra goldfield with established mining operations
• Neighbouring Westgold's Paddy's Flat operation provides processing options
• Proven Murchison region with multiple operating gold mills
• Established road and power infrastructure reduces development costs

Near-Term Catalysts:

• At least 3 rigs recommencing drilling in January 2026
• Mining lease applications planned for Mulga Bill, Eaglehawk, and Saltbush in the New Year
• Strong cash position supports aggressive exploration programmes
• Development pathway studies progressing toward production decisions

"Our systematic exploration highlights the massive potential for the Side Well project, indicating strong resource growth into 2026 and beyond. With multiple rigs growing the resource base we also remain focused on our development path," stated Andrew Paterson, Managing Director.

Why Should Investors Follow Great Boulder Resources?

The achievement of the 1+ million ounce milestone represents more than just a numerical target. Moreover, it establishes Side Well as a significant gold system with genuine development potential in one of Australia's premier mining regions.

Key Investment Attractions:

Immediate Upside Catalysts:

• Recent high-grade intersections not included in current resource
• Deep targets at Mulga Bill showing visible gold 200m below previous drilling
• Underexplored prospects across 1.5km+ strike lengths
• Mining studies advancing toward development decisions

The combination of substantial resource scale, high-grade components, strategic location, and multiple growth vectors positions Great Boulder favourably. Furthermore, the company continues delivering on its multi-million ounce potential.

With systematic exploration continuing to expand the resource base and development studies progressing, Side Well represents a compelling growth story. Additionally, its location in the proven Murchison goldfield strengthens the investment thesis.

Great Boulder has successfully established Side Well as a major gold system with genuine multi-million ounce potential. The 1+ million ounce milestone, combined with high-grade cores, district-scale exploration opportunities, and strategic infrastructure advantages, positions the company for continued resource growth and development advancement in 2026 and beyond.

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