Great Southern Mining Ltd
Deep diamond drilling at Great Southern Mining Ltd represents a pivotal moment for the company as it seeks to unlock the subsurface potential of its Golden Boulder discovery. Great Southern Mining (ASX: GSN) has commenced this strategic drilling campaign at its 100% owned Golden Boulder project within the Duketon Gold Project in Western Australia, marking the first diamond drilling in the area and the first hole beyond 155m depth in the primary mineralised zone.
Exceptional Previous Results Drive Deep Drilling Strategy
The decision to pursue deep diamond drilling comes following outstanding shallow drilling results that have revealed the significant scale of the Golden Boulder system. Furthermore, these results have provided strong justification for deeper exploration to understand the structural controls on mineralisation.
Previous intercepts from the Main Line mineralisation demonstrate remarkable consistency across the 3.5km mineralised strike:
| Hole ID | Intercept | Grade | Notable High-Grade Zones |
|---|---|---|---|
| 25GBRC009 | 5m at 14.57 g/t Au from 41m | 14.57 g/t | 1m at 70.94 g/t Au |
| 25GBRC030 | 5m at 5.1 g/t Au from 25m | 5.1 g/t | 1m at 23.9 g/t Au |
| 25GBRC064 | 5m at 3.5 g/t Au from 39m | 3.5 g/t | – |
| 25GBRC054 | 6m at 6.7 g/t Au from 48m | 6.7 g/t | 1m at 34.5 g/t |
The company has secured up to $220,000 in Western Australian Government Exploration Incentive Scheme (EIS) co-funding for this strategic drilling campaign. Consequently, this will target both the Ogilvies location with a 700m deep hole and the Main Line mineralisation where previous drilling has defined the extensive mineralised zone.
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Understanding Structural Controls: Why This Matters for Investors
Structural controls refer to the geological features – such as faults, shears, and rock contacts – that influence where gold mineralisation occurs. In addition, understanding these controls is crucial for several key reasons:
• Predictive Power: Once understood, structural controls allow geologists to predict where additional mineralisation might occur
• Resource Expansion: Deep drilling can reveal whether surface mineralisation extends to depth, potentially multiplying the size of a discovery
• Economic Viability: Deeper, structurally controlled deposits often contain higher-grade zones that improve project economics
At Golden Boulder, GSN has identified that the area sits within a prominent structural trend comprising several gold-bearing faults. However, the interpreted first-order Rosemont Fault is of particular significance, as major gold deposits in the Duketon Gold Belt commonly occur directly on or in proximity to these first-order structures.
The Golden Boulder area sits within a prominent structural trend where multiple fault systems converge. Integration of geophysical datasets, including a reprocessed and reinterpreted Geoscience Australia regional seismic line, indicates that these first-order shears are mantle-tapping structures. For instance, these structures are capable of transmitting gold-bearing fluids from depth to surface.
Gold deposition is favoured where these fluids encounter chemically reactive lithologies or dilation zones created by structural flexures. Furthermore, fluid leakage from deeper deposits may generate surface anomalies along shear outcrops, as evidenced at Golden Boulder. The area contains approximately 50 historical gold workings and GSN has identified at least three lines of mineralisation: the Main Line, East Line and Ogilvies.
Strategic Deep Diamond Drilling Programme
The initial deep diamond hole at the Ogilvies prospect will be drilled up to a depth of 700m towards the west. This hole aims to intersect multiple structures including the Mulga Queen Fault, and potentially the Rosemont Fault at depth. Consequently, this hole will provide highly valuable structural and stratigraphic data which will aid deeper exploration in the Golden Boulder area.
A second diamond hole has been planned to intercept the Main Line mineralisation at a steep angle up to a depth of 220m. This hole targets the known gold-bearing structure to better understand the controls on mineralisation along the Main Line trend.
The deep diamond drilling at Great Southern Mining Ltd will provide the first geological, stratigraphic and structural data across the Rosemont-Mulga Queen Shear Zone within GSN's tenure. However, this invaluable information can be applied to belt-wide exploration, potentially identifying new targets across the broader project area.
Amy Clarke Discovery Adds Portfolio Strength
Complementing the Golden Boulder program, GSN's late-2025 aircore drilling at the emerging Amy Clarke discovery defined mineralisation over a 4.7km strike. Furthermore, the better intercepts included:
• 17m at 1.4 g/t Au from 20m, including 1m at 11.2 g/t Au (25ACAC0105)
• 2m at 23.9 g/t Au from 10m (25ACAC0007)
• 11m at 1.2 g/t Au from 25m (25ACAC0057)
• 5m at 3.4 g/t Au from 8m and 1m at 3.2 g/t Au from 37m (25ACAC0132)
The Amy Clarke discovery demonstrates GSN's ability to identify and develop multiple gold prospects across its tenure. In addition, both Golden Boulder and Amy Clarke are scheduled for major drilling programs of 10,000 to 15,000 metres commencing in late-April to May 2026.
Strategic Timing and Full Funding Position
GSN's timing for this expanded drilling campaign is strategically sound. The company completed a strongly supported $4.6 million equity capital raising in March 2026, ensuring full funding for upcoming exploration programs. Consequently, this financial position allows GSN to pursue an aggressive exploration strategy without funding constraints.
"This diamond drilling will be critical to GSN's understanding of the controls on mineralisation at Golden Boulder. This is certainly a very large gold system with at least three mineralised trends propagating to surface and extending over a strike length in excess of 3.5km," said Matthew Keane, Managing Director.
The strategic approach to deep diamond drilling at Great Southern Mining Ltd reflects the company's confidence in the Golden Boulder system's potential. However, the program also represents a calculated risk to unlock significant value for shareholders through better understanding of the deposit's structural architecture.
Multi-Asset Portfolio Delivers Diversified Exploration
Beyond the gold-focused drilling at Golden Boulder, GSN completed an 811.5m diamond hole into the Diorite Hill Layered Intrusive Complex within the East Laverton Project. Furthermore, this hole targeted stratigraphic horizons considered prospective for reef-style PGE-nickel-copper mineralisation, demonstrating the company's diversified commodity approach.
Preliminary logging revealed a complex sequence of mafics and ultramafics, with trace sulphides including disseminated pyrrhotite and pyrite. An unidentified silver-coloured mineral was observed at multiple intervals, with samples collected for detailed analysis. Consequently, assay results are expected in 6 to 8 weeks.
The sequences observed from preliminary logging are consistent with continued cyclic emplacement of large volumes of mantle-derived melt that cooled slowly in deep crustal magma chambers. In addition, selective samples are being collected throughout the sequence for detailed geochemical analysis.
Investment Thesis: Scale, Grade, and Strategic Location
GSN presents a compelling investment proposition built on several key pillars that justify the deep diamond drilling at Great Southern Mining Ltd:
Large-Scale Gold System: The Golden Boulder discovery spans over 3.5km strike with multiple mineralised trends, indicating a significant gold system with substantial expansion potential.
High-Grade Intercepts: Previous drilling has consistently delivered high-grade results, including 70.94 g/t Au and 34.5 g/t Au, demonstrating the system's grade potential.
Strategic Location: All projects are located within 40km of operating mills and major operations in world-renowned mining districts. However, this provides potential processing solutions and reduces development risks.
Fully Funded Exploration: The recent $4.6 million capital raising ensures GSN can execute its exploration strategy without near-term funding pressures.
Government Support: EIS co-funding demonstrates government recognition of the projects' prospectivity and provides cost-effective exploration capital.
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Why This Deep Drilling Campaign Matters
The commencement of deep diamond drilling at Great Southern Mining Ltd represents a critical inflection point that could reveal the true scale and grade potential of this large gold system. Furthermore, the program addresses key geological questions that will determine the project's future development pathway.
With upcoming major drilling programs at both Golden Boulder and Amy Clarke, complemented by PGE-base metals exploration at East Laverton, GSN offers investors exposure to a diversified exploration portfolio. In addition, multiple near-term catalysts provide numerous opportunities for value creation.
The combination of strong previous results, strategic location advantages, full funding, and government support positions GSN favourably as drilling results emerge. However, the deep diamond drilling at Great Southern Mining Ltd will provide crucial data that could transform understanding of the Golden Boulder system's architecture and potential.
"Great Southern Mining has assembled a compelling portfolio of gold and base metals projects in proven mining districts. With deep diamond drilling now underway at Golden Boulder and major RC programs planned for both Golden Boulder and Amy Clarke, the next 6-12 months could be transformational for understanding the true scale of these discoveries."
The deep diamond drilling programme represents more than just another exploration campaign. Consequently, it could define GSN as a significant new player in Australian gold exploration, with results potentially reshaping investor perceptions of the company's asset quality and growth potential.
Ready to Explore GSN's Deep Drilling Potential?
Great Southern Mining's deep diamond drilling programme at Golden Boulder represents a pivotal moment that could unlock significant value for shareholders. With over 3.5km of proven mineralised strike, exceptional high-grade intercepts including 70.94 g/t Au, and full funding secured through their recent $4.6 million capital raising, GSN is positioned to deliver transformational drilling results over the coming months. The company's strategic location within 40km of operating mills, combined with government EIS co-funding support, provides multiple advantages for potential resource development. To discover how GSN's diversified exploration portfolio across proven mining districts could reshape your investment strategy, visit gsml.com.au for comprehensive project details and the latest drilling updates.
