Side Well Project

About The Side Well Gold Project

The Side Well Gold Project is situated immediately east of the town of Meekatharra in the Murchison region. The project overlies the Meekatharra – Wydgee greenstone belt and includes upper greenschist-facies rocks of the Luke Creek and Mt Farmer groups. Within the project area lithologies comprised of ultramafics, basalts, banded iron formation and felsic to intermediate volcaniclastics are folded into a large regional syncline known as the Pollele syncline. Alluvium and lacustrine clays overlie the area.

Side Well is ideally located next to Meekatharra in WA, adjacent to Westgold Resources’ Paddy’s Flat operation and only 25km from Westgold’s 1.8Mtpa Bluebird Mill

Current gold deposits and other targets at the Side Well Gold Project

Project Overview

Great Boulder has identified two main gold rich corridors within the Side Well project. The Central Corridor, which sits within felsic to intermediate volcaniclastics beneath a thin veneer of alluvial cover in the centre of the Polelle Syncline, contains the Eaglehawk, Mulga Bill, Loaded Dog and Flagpole gold deposits within a strike extent spanning more than 6km. Mulga Bill and Eaglehawk are the most advanced of these, with a combined Mineral Resource estimate of 742,000oz Au (Indicated + Inferred; ASX 18 December 2025) over a strike extent of approximately 2.5km. This resource remains open at depth and along strike to the north and south.

The adjacent Eastern Corridor, located on the eastern limb of the Polelle Syncline, is a zone dominated by mafic and ultramafic rocks hosting anomalous gold and associated pathfinder elements over more than 22km of strike. These rocks are the stratigraphic equivalent of the ~2Moz Paddy’s Flat group located on the opposite limb of the syncline. Drilling to date has defined mineral resources at the Ironbark, Saltbush and Golden Bracelet deposits which contain a combined total of 214,000oz (Indicated + Inferred). Numerous other highly prospective gold targets are being explored along the Eastern Corridor.

In addition to the current near-surface gold resources at Side Well the Company is now testing the deeper potential within the Mulga Bill – Eaglehawk gold system, with a series of deeper holes which commenced in October 2025. The two initial holes of the program successfully intersected high grade gold mineralisation at depth, including a spectacular intersection of up to 4,434g/t Au approximately 500m down hole 25MBRCD002A. The hole drilled immediately prior to this discovered two new gold lodes approximately 90m west of the resource in hole 25MBRCD001A. New discoveries and depth extensions such as these demonstrate the potential of Mulga Bill to continue growing as drilling continues.

With a current resource base of over 1Moz, a landmark deep drilling discovery, and a strong pipeline of targets across more than 40km of prospective strike, Side Well is rapidly emerging as a major gold system in the Murchison. Ongoing exploration is expected to continue expanding the project’s endowment, while the strategic collaboration with Westgold provides a credible pathway to unlock development and realise the full value of the project.

A cross section showing the position of the high-grade intersection at depth in hole 25MBRCD002A: 4,434g/t Au

MINERAL RESOURCES

The current combined Mineral Resource Estimate for the Side Well Project sits at 16Mt @ 2.0g/t Au for 1,021,000oz, with resources at Mulga Bill, Eaglehawk, Flagpole, Ironbark, Saltbush and Golden Bracelet.

Mulga Bill

Mulga Bill is the flagship deposit at Side Well and the largest in the MRE, with approximately 63% of the project’s 1.02Moz resource base. It is defined by a robust, high-grade core that extends to depth. The December 2025 MRE stands at 8,294kt @ 2.4g/t for 642,000oz, including 496,000 indicated ounces.

Extensional drilling shows that mineralisation is continuous and extend along strike. Deep diamond drilling indicated continuity at depth, delivering the project’s the deepest and highest-grade intersection in the history of the deposit with a 4,434g/t Au intercept. Metallurgical test work has confirmed gold recoveries of up to 99.7% using standard processing methods, with a relatively coarse grind of 106um and fast leach times with moderate cyanide consumption (ASX announcements 15 January and 7 May, 2025).

Cross section of hole 25MBRCD001A showing the two new high-grade discoveries up to 90m west of the Mulga Bill resource, an area which is poorly tested by drilling

Eaglehawk

Eaglehawk is located immediately along strike from Mulga Bill within the Central Corridor. Drilling by Great Boulder has intersected the same mineralised veins sets as those seen at Mulga Bill, meaning Eaglehawk is essentially the northern continuation of the same deposit.

Eaglehawk is less well defined than the better-drilled Mulga Bill area. As drilling progresses the current resource is expected to extend to depth in a similar manner to that at Mulga Bill.

While the combined Mulga Bill – Eaglehawk resource currently spans a strike length of approximately 2.5km, gold mineralisation remains open to the north of Eaglehawk where AC drilling has encountered gold and associated pathfinder elements over at least another 500m of strike.

Long section showing the Mulga Bill and Eaglehawk resource envelopes with recent drilling intersections

Ironbark

Ironbark is the most advanced deposit in the Eastern Corridor, with a MRE of 1,423kt @ 2.7g/t for 122,000oz. A Mining Lease Application has been lodged over the deposit, and Mining Agreement negotiations are progressing with the local Yugunga-Nya Aboriginal Corporation.

In July 2025 the Company announced the results of a Scoping Study for open pit mining at Ironbark. The study, which was based upon the previous 100,000oz Au MRE announced in November 2023, indicated a potentially robust economic case for a simple truck-and-shovel surface mining operation utilising toll treatment at one of the nearby mills in the area. Since this study was announced additional drilling has extended the Ironbark deposit by approximately 200m further south, with the MRE updated in December 2025.

Ironbark long section showing the resource envelope, the July 2025 scoping study pit design and recent diamond drilling intersections

A plan view of Ironbark showing the July 2025 scoping study pit design. Note the newly discovered high grade zone extending south beyond the pit limits.

Growth Targets

Great Boulder will continue expanding the Side Well resource inventory by ongoing drilling to test a strong pipeline of exploration targets, including several highly prospective areas that remain undrilled. This continues the process of conventional exploration that has discovered over 1 million resource ounces, utilising cheap auger geochemistry to generate initial targets followed by Air-core drilling, RC drilling and Diamond drilling.

In parallel to the early-stage exploration programs the Company will continue defining and extending known resources. The ongoing deep drilling program at Mulga Bill – Eaglehawk is an example where step-out holes beneath a well-defined mineral system have identified additional high-grade gold mineralisation which is expected to contribute additional resource growth as the programs continue.

Exploration History

In the early 1980’s Kalgoorlie-based prospector and explorer Scott Wilson was among the first people to recognise that the Meekatharra greenstone belt continued beneath shallow soil cover north of Meekatharra. After studying regional aeromagnetic maps of the area produced by the Bureau of Mineral Resources. Scott pegged a series of exploration licences between Meekatharra and Andy Eell, an area in which he still maintains an interest more than 35 years later. He went on to strike joint venture agreements with a series of exploration companies, leading to the discovery of gold at Andy Well by WMC Resources and the first significant intersection at Mulga Bill by Dominion Mining.

In joint venture with Scott’s private company Murchison Resources, regional exploration has been conducted around Side Well by a number of companies over the past 35 years including Dominion Mining (1992 to 1995), WMC Resources (1996-97), Accent Resources (2009) and Doray Minerals (2010 to 2016). Dominion was the first company to identify significant gold mineralisation in drilling with intersections such as 2m @ 1.67g/t Au and 4m @ 1.4g/t Au in regional RAB traverses [1].

Dominion Mining and WMC Resources explored the greenstone belt from Andy Well to Side Well during the 1990’s. Dominion discovered significant gold mineralisation at Side Well in 1993, including 26m @ 2.19g/t in hole HAR3015. WMC subsequently assumed majority ownership of the project, and shortly afterwards WMC drilled the discovery holes at Andy Well. WMC eventually concluded that the project area did not meet their exploration criteria of a 6Moz discovery, commenting in their 1998 report that “potential for a near-surface WMC-sized position (e.g. 6Moz) was significantly downgraded. The potential for smaller, perhaps million ounce, positions remains significant.[2]” The decision by WMC to leave the area eventually led to the Andy Well and Side Well projects being picked up by Doray Minerals in joint venture with Scott Wilson – a deal done over a handshake at Kalgoorlie’s Palace Hotel during the Diggers & Dealers mining conference.

At Side Well Doray was successful in identifying high-grade gold in drilling at Matilda (3m @ 35.48g/t Au from 76m in hole MNAC0463) and at Dominion’s original discovery hole site, now named Mulga Bill where several significant hits in Air-Core (AC) and Reverse Circulation (RC) drilling included 10m @ 3.41g/t Au from 185m in SWRC006, 14m @ 5.30g/t Au from 86m in SWRC012 and 5m @ 6.69g/t Au from 110m in MNAC0454. In January 2013 Doray flew a heli-TEM survey over the project area which provided additional detail for their structural interpretation on the controls to mineralisation. After 2015, Doray’s exploration focus shifted closer to Andy Well as they experienced success at Gnaweeda, while the corporate focus shifted to the ramp-up of operations at Deflector, south of Yalgoo.

Great Boulder entered into a Joint Venture agreement with Scott Wilson’s Zebina Minerals Pty Ltd in 2020 and commenced drilling in August that year. Early target generation work by GBR in 2020 led to the first high-grade intersections at Mulga Bill, announced in early May 2021, and the discovery of the Ironbark and Loaded Dog prospects in late 2021.