Great Southern Mining Reports Strong Drilling Results North of Mon Ami Deposit

Drilling extends Mon Ami mineralisation north into Blanc Plat target

Great Southern Mining has returned results from a 10-hole reverse circulation program at the Blanc Plat target — located approximately 200m north of the company’s Mon Ami Gold Project, 12km south of Laverton in Western Australia — that indicate Blanc Plat may be a northern extension of the main Mon Ami deposit along the gold-bearing Barnicoat Shear Zone. The standout intercept came from hole 26MARC012, which returned 14m at 1.05 g/t Au from 36m, including 1m at 6.33 g/t Au. The 10-hole program drilled 1,392m total and was designed to test for extensions to the north of Mon Ami’s existing JORC 2012 Resource of 1.56 Mt at 1.11 g/t Au for 55,500 oz.

The results point to potential resource growth adjacent to an already well-defined deposit that sits within close trucking distance of multiple operating and emerging gold processing facilities in the Laverton District.

Blanc Plat results point to shallow oxide upside

The recent RC drilling at Blanc Plat returned a spread of intercepts that, when combined with historic results, reinforce continuity along the northern extension of the Barnicoat Shear Zone. Management has flagged the shallow oxide angle as particularly important for economic potential — approximately 65% of all gold mineralisation greater than 0.2 g/t Au intercepted at Blanc Plat sits in the oxide zone (saprolite clays or weathered saprock), which is typically cheaper and simpler to process than deeper primary ore.

Historic drilling at Blanc Plat has also delivered encouraging results:

• 2m at 4.8 g/t Au from 70m (MLRC009)
• 2m at 3.23 g/t Au from 100m (ML032)

Matthew Keane, Managing Director

“…While it is still early days at Blanc Plat, this target is showing signs of being a potential extension to the Mon Ami deposit, which could complement the existing resource. Of particular importance, is the prospect for further oxide mineralisation.”

The 200m untested gap between Blanc Plat and Mon Ami

The approximately 200m strike between Mon Ami and Blanc Plat remains largely untested, but recent extensional drilling suggests the two systems may connect. Hole 26MARC006, drilled in the gap zone, returned 19m at 1.12 g/t Au from 213m, including 1m at 4.00 g/t Au and 1m at 5.00 g/t Au — a 55m down-plunge extension to the Mon Ami Resource. The intercept sits 140m southwest of recent Blanc Plat hole 26MARC008.

Mineralisation also remains open to the north over a 425m strike length to the tenement boundary. The potential to link Blanc Plat and Mon Ami into a larger contiguous system adds a layer of exploration upside that could materially expand the resource footprint.

Understanding oxide gold and why proximity to mills matters

Oxide mineralisation refers to gold-bearing material that sits close to surface and has been weathered over geological time. This weathering breaks down the host rock into clays and soft saprock, which makes the ore easier and cheaper to process than deeper, unweathered primary ore. Oxide deposits can often be mined using conventional open-pit methods and processed using simpler techniques like heap leaching or basic milling — both of which reduce capital costs and speed up development timelines.

For a project like Mon Ami, the oxide angle is critical. The deposit sits within a 50km trucking radius of multiple operating and emerging gold processing facilities, including the Granny Smith plant (owned by Gold Fields) approximately 12km to the west. This proximity means Mon Ami could be developed using a toll treating model — trucking ore to a third-party mill rather than building its own processing plant. For a smaller deposit, this model can be the difference between economic viability and remaining on the shelf.

That regional consolidation context is what Managing Director Matthew Keane is referring to when he says Mon Ami is “strategically valuable.” A deposit that can be trucked to an existing mill becomes an attractive bolt-on opportunity for operators looking to feed spare capacity.

Mon Ami’s growth and development pathway

The recent extensional drilling at Mon Ami has shown the resource is open down-dip, down-plunge and to the north. Key intercepts from the first six holes of the RC program include:

1. 16m at 3.37 g/t Au from 178m, including 4m at 8.54 g/t Au and 2m at 6.86 g/t Au (26MARC001)
2. 6m at 1.83 g/t Au from 150m, including 1m at 7.28 g/t Au, plus 16m at 1.28 g/t Au from 281m (26MARC004)
3. 19m at 1.12 g/t Au from 213m (26MARC006)

These intercepts extend the main Vertical Lode by 30m to 60m down-dip and 55m down-plunge, demonstrating that the resource has room to grow beyond its current 1.56 Mt at 1.11 g/t Au for 55,500 oz JORC 2012 estimate.

From a development perspective, Mon Ami already has several critical approvals and studies completed:

• Granted Mining Licence M38/1256
• Special Licence L38/349 granted for haulage route
• Archaeological and ethnographic surveys completed
• Flora and fauna surveys completed
• Metallurgical studies and waste rock classification studies completed

These prerequisites position Mon Ami as a potential near-term development opportunity, though the company has not yet made a final investment decision.

What’s next: an aggressive multi-project drilling phase

Great Southern Mining is moving through an active exploration phase across its portfolio, with multiple near-term assay catalysts ahead:

• Assays pending for 38 RC holes at the Golden Boulder discovery (Duketon Gold Project)
• Assays pending for 18 RC holes at the emerging Amy Clarke discovery (Duketon Gold Project)
• Diamond drilling ongoing at Mt Dillon (Edinburgh Park Project, Queensland) — joint venture with Gold Fields Ltd
• Follow-up mapping, surface geochemistry and infill/extensional drilling planned at Blanc Plat

Matthew Keane, Managing Director

“This is an incredibly busy, exciting and aggressive exploration phase for the Company with the team focussing on continued drilling at the Duketon Gold Project in Western Australia with the Company’s joint venture partner, Gold Fields Ltd, chasing monster intrusive related gold systems at the Edinburgh Park Project in Queensland.”

The Blanc Plat results add another layer to Mon Ami’s growth story — one that combines shallow oxide potential, proximity to processing infrastructure, and a largely untested strike corridor that could tie together two mineralised zones into a single, larger system. For investors tracking resource growth stories in Western Australia’s Laverton district, this is a project to watch as assays from the broader drilling campaign start to flow through.

Could Blanc Plat unlock a larger contiguous gold system at Mon Ami?

Great Southern Mining’s recent drilling has returned promising shallow oxide intercepts at Blanc Plat, including 14m at 1.05 g/t Au from just 36m depth, suggesting a potential northern extension to the existing 55,500 oz Mon Ami Resource. With approximately 65% of Blanc Plat’s mineralisation sitting in the oxide zone and a largely untested 200m strike gap between the two deposits, the company is positioning Mon Ami as a near-term development opportunity within trucking distance of multiple Laverton processing facilities.

For a detailed breakdown of the drilling results, regional consolidation context and what’s next in Great Southern Mining’s exploration pipeline, visit the Great Southern Mining investor centre.