Great Southern Mining Launches Largest-Ever RC Drill Programme at Mon Ami

Great Southern Mining Pulls the Trigger on Its Largest-Ever Drill Program

The Great Southern Mining Mon Ami gold project RC drilling program marks a significant milestone for Great Southern Mining Ltd (ASX: GSN), which has commenced Reverse Circulation (RC) drilling at the Mon Ami Gold Project in Western Australia. The company has described this as its largest drilling campaign since acquiring the Duketon Gold Project tenure in 2021. According to the latest ASX announcement on 24 June 2026, the wider programme totals up to 20,000 metres of RC drilling across Great Southern Mining Ltd's Western Australian portfolio, with activities fully funded and sequenced across three key targets.

The programme begins at Mon Ami, where existing JORC (2012) resources are being tested for extensions, before the RC rig moves on to the Golden Boulder and Amy Clarke discoveries within the Duketon Gold Project.

Drilling Kicks Off at Mon Ami With Clear Objectives

Mon Ami is located approximately 12 km south of Laverton, WA, on a granted mining licence within the Barnicoat Shear, a regional geological structure that already hosts multiple gold deposits to the north, such as the Barnicoat Mine and Ida H Mine (owned by Genesis Minerals, ASX: GMD).

The project contains a defined JORC (2012) Mineral Resource of 1.56 Mt at 1.11 g/t Au for 55,500 ounces of gold (as reported on 21 July 2021). According to Great Southern Mining Ltd, this resource remains open to the north, northwest and down dip, meaning previous drilling has not closed off mineralisation in those directions.

The current Mon Ami RC programme totals up to 3,000 metres, with two main aims:

• Test depth extensions and follow up previous high-grade intercepts within the existing resource area
• Test targets located approximately 250 metres north of the current Mineral Resource

The company has estimated the Mon Ami campaign will take around three weeks. On completion, the same RC rig is scheduled to mobilise directly to the Golden Boulder discovery within Great Southern Mining Ltd's 100%-owned Duketon Gold Project.

A Sequenced Multi-Target RC Drilling Campaign

The ASX announcement confirms that Mon Ami is part of a broader up to 20,000 metre RC drilling programme spanning several Western Australian projects. Furthermore, this is the largest RC campaign undertaken by Great Southern Mining Ltd since it entered the Duketon district.

Drilling has been structured as a pipeline of activity across three main targets:

Golden Boulder and Amy Clarke have already shown multi-kilometre strike lengths in earlier drilling and aircore work. According to the company's previous disclosures, both prospects remain open along strike and at depth, indicating that the limits of the mineralised systems have not yet been defined.

Programme scale highlight: The ASX announcement states that the up to 20,000 metre RC programme represents the largest drilling initiative by Great Southern Mining Ltd since the Duketon tenure was acquired in 2021.

What Is RC Drilling and Why Does It Matter?

Reverse Circulation (RC) Drilling Explained

Reverse Circulation drilling is one of the most widely used techniques in Australian gold exploration. It is designed to balance cost, speed, and sample quality.

In simple terms:

• A large pneumatic drill with a hardened bit is driven into the ground
• Compressed air is used to bring rock chips back up through the centre of the drill rods
• These rock chips are collected at regular intervals, commonly every metre, then logged and sampled
• Samples are sent to a laboratory to measure the concentration of gold (for example, g/t Au) and other elements

RC drilling differs from diamond drilling, which retrieves core (solid cylinders of rock). RC produces chips rather than core but is generally:

• Faster in terms of metres drilled per day
• Lower cost per metre, which allows more metres to be drilled within a set budget
• Well suited to defining the shape and grade of near-surface and moderately deep mineralisation

For projects like Mon Ami, Golden Boulder, and Amy Clarke, where mineralisation has already been identified and needs to be stepped out or extended, RC drilling provides a practical way to:

• Test extensions along strike (horizontal length) and at depth
• Collect enough data to update existing Mineral Resource estimates or prepare maiden resources at new prospects
• Prioritise zones for any later, more detailed diamond drilling

Why Does RC Drilling Matter to Investors?

From an investor perspective, RC drilling often drives the short to medium-term news flow for an exploration company such as Great Southern Mining Ltd. Each RC programme can deliver:

• New intercepts that indicate continuity or expansion of mineralisation
• Data that may support resource growth, which can influence how a project is valued
• Information on grade distribution, which is important when considering future economic studies

At Mon Ami, RC results have the potential to inform any future update to the 55,500 ounce JORC Mineral Resource, as well as test whether the northern target 250 metres beyond the current resource contains additional zones of gold mineralisation. Consequently, results could also confirm the extent of previous high-grade intercepts at depth.

At Golden Boulder and Amy Clarke, the ASX announcement indicates that RC drilling will focus on large mineralised trends already outlined over 3.5 km and 4.7 km respectively. If these programmes define consistent zones with suitable width and grade, they could support maiden Mineral Resource estimates in due course, subject to sufficient drilling density.

Funding Position and Programme Scale

The announcement confirms that Great Southern Mining Ltd is fully funded for all planned drilling activities. The company recently settled the final tranche of a $4.6 million equity placement in early June 2026.

Key programme metrics are summarised below:

From an investment point of view, funding certainty reduces the risk that drilling programmes could be delayed or cut back due to capital constraints. In addition, it supports the planned continuous sequence of drilling across the three targets, which can help maintain a stream of technical updates to the market.

Location and Infrastructure Advantages

The Mon Ami Gold Project lies within trucking distance of multiple operating and emerging gold processing facilities in the Laverton district. According to Great Southern Mining Ltd, all of its Laverton and northern Queensland projects are located within roughly 40 km of operating mills and major operations.

For investors, the location offers two potential advantages if future studies support development:

• Development flexibility: Access to nearby processing plants can provide options for toll treatment, which may reduce the need for stand-alone processing infrastructure at smaller deposits
• Regional consolidation appeal: Projects situated within established mining districts, especially near existing mills, may attract attention from operators looking for additional ore sources, subject to commercial agreements

The Barnicoat Shear, where Mon Ami is located, already hosts multiple gold deposits and operating mines. This provides geological context that the broader corridor has been able to support economic gold projects in the past, although each deposit still requires its own technical and economic assessment.

Investment Case: Multiple Targets Across a Proven Gold District

The commencement of the Great Southern Mining Mon Ami gold project RC drilling program positions the company for an extended period of exploration activity across several established targets in a well-known gold region.

Key elements for investors to monitor include:

• Resource growth potential at Mon Ami

  • Extensions to the current 1.56 Mt at 1.11 g/t Au for 55,500 oz JORC Mineral Resource
  • Results from the northern target located 250 m beyond the current resource boundary

• Advancement of the Golden Boulder discovery

  • The ASX announcement notes mineralisation already outlined over 3.5 km, which remains open along strike and at depth
  • RC drilling here aims to refine the understanding of grade distribution and continuity along this trend

• Scale and continuity at Amy Clarke

  • Mineralisation at Amy Clarke has been traced over 4.7 km, based on aircore drilling campaigns in 2021 and 2025
  • The planned RC drilling will test priority zones identified from these earlier campaigns

• Continuous exploration news flow

  • The sequencing of drilling from Mon Ami to Golden Boulder and then Amy Clarke, underpinned by the current funding position, suggests a relatively consistent flow of updates as results are received and interpreted

Key takeaway for investors: Great Southern Mining Ltd is conducting a fully funded, up to 20,000 metre RC drilling programme across three Western Australian gold targets, starting with Mon Ami. The programme focuses on extending an existing JORC Mineral Resource and testing large mineralised trends at Golden Boulder (3.5 km) and Amy Clarke (4.7 km) that remain open along strike and at depth.

Frequently Asked Questions

What Is the Current Mineral Resource at Mon Ami?

According to the ASX announcement and previous reporting (21 July 2021), Mon Ami hosts a JORC (2012) Mineral Resource of 1.56 million tonnes at 1.11 g/t gold for 55,500 ounces of contained gold.

How Many Metres of RC Drilling Are Planned at Mon Ami?

The present RC programme at Mon Ami comprises up to 3,000 metres as part of the broader up to 20,000 metre RC programme across Great Southern Mining Ltd's Western Australian projects.

What Will Happen After Drilling Finishes at Mon Ami?

Once the estimated three-week RC programme at Mon Ami is completed, the drill rig is scheduled to mobilise immediately to the Golden Boulder discovery within the Duketon Gold Project. RC drilling at the Amy Clarke discovery is planned to follow Golden Boulder.

Is the Drilling Programme Funded?

Yes. The company has stated it is fully funded for all planned drilling activities, following settlement of the final tranche of a $4.6 million equity placement in early June 2026.

Why Is the Duketon and Laverton Region Important for Gold Exploration?

The Laverton district and Duketon belt are established gold-producing regions in Western Australia, hosting multiple operating mines and processing facilities. Mon Ami sits on the Barnicoat Shear, which also hosts other gold deposits such as Barnicoat and Ida H. This regional context indicates that the area has supported gold mineralisation historically, although each new project must still demonstrate technical and economic viability in its own right.

Glossary of Key Terms

• RC drilling (Reverse Circulation drilling): A drilling technique using compressed air to return rock chips to surface for sampling. It is widely used in gold exploration due to its speed and cost effectiveness
• JORC (2012) Mineral Resource: A publicly reported estimate of mineralisation prepared under the 2012 edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves
• g/t Au: Grams of gold per tonne of rock, the standard unit used to report gold grades
• Strike: The horizontal direction or length of a mineralised body on the surface or in a geological model
• Open along strike / at depth: Indicates that the known mineralisation has not been fully defined by drilling in those directions and may continue further
• Barnicoat Shear: A regional shear zone in the Laverton district that hosts multiple gold deposits and provides the structural setting for the Mon Ami Gold Project

The Great Southern Mining Mon Ami gold project RC drilling program, alongside the subsequent programmes at Golden Boulder and Amy Clarke, provides a structured, fully funded exploration sequence in a recognised Australian gold district. Investors are consequently likely to focus on the potential for resource growth and the definition of new mineralised zones across these targets as results emerge.

Want to Follow Great Southern Mining's Largest-Ever Drill Programme?

Great Southern Mining Ltd (ASX: GSN) is now drilling across three Western Australian gold targets — Mon Ami, Golden Boulder, and Amy Clarke — in a fully funded, up to 20,000 metre RC programme. With an existing JORC Mineral Resource at Mon Ami and multi-kilometre mineralised trends awaiting testing at its Duketon Gold Project, this is a pivotal period for the company. To learn more about GSN's projects and investment proposition, visit the official website at gsml.com.au.