Mandalay Resources Expands High-Grade Gold Discovery at Brunswick South

• All three exploration drillholes intersected high-grade gold veining, with the highest grade reaching 265.0 g/t gold and 0.7% antimony over 0.29 metres
• New discovery sits just 300 metres from active underground access drives, enabling cost-effective and rapid development
• Mineralisation confirmed across 175-metre strike length and 50-metre down-dip extent, with significant expansion potential
• Discovery timing aligns with anticipated merger completion with Alkane Resources on 5 August 2025
• Additional drilling programme launched to define full resource potential of the emerging discovery

Mandalay Resources Corporation (TSX: MND, OTCQB: MNDJF) is a Canadian-based natural resource company operating two key producing assets: the Costerfield gold-antimony mine in Australia and the Björkdal gold mine in Sweden. The company maintains a strategic focus on growing production whilst reducing operational costs to generate sustainable cash flow for shareholders.

New Discovery at Brunswick South

The Brunswick South discovery is located within 300 metres of existing underground infrastructure. The discovery area lies within the broader Brunswick deposit system, which was previously mined during the 1990s through open-pit methods and later via underground operations from 2018 onwards under Mandalay's management.

The Brunswick vein system demonstrates remarkable geological consistency, with mineralisation tested over a 2,000-metre length near surface with minimal geological disruption. This linear characteristic distinguishes it from other veins within the Costerfield field. The vein occupies the structural hinge of an open north-south striking anticline and typically contains higher proportions of stibnite relative to quartz compared to other Costerfield veins.

President and CEO Frazer Bourchier emphasised the discovery's significance:

"We are extremely excited about the new discovery at Brunswick South following on the heels of our success at True Blue. Brunswick South is within 300 metres of existing underground infrastructure, providing potential near term mine life extension of Costerfield."

The geological team's reinterpretation of previously drilled low-grade intersections suggested that interference from flat-lying faulting was affecting earlier results. This insight led to the targeted drilling programme that ultimately delivered the successful discovery.

Drill Results and Mineralisation Details

The three-hole drilling programme returned high-grade gold intersections across all drillholes. Drill hole BD387 intersected the Brunswick vein approximately 270 metres south of existing development limits, returning 76.6 g/t gold over 0.49 metres downhole. The intersection consisted of healed quartz breccia containing visible gold, indicating high-grade mineralisation quality.

BD388, positioned 175 metres south of BD387, encountered even higher-grade mineralisation at 265.0 g/t gold and 0.7% antimony over 0.29 metres downhole. This intersection showed clusters of fine visible gold evenly distributed throughout the quartz, with stibnite present as a late-stage vein infill phase. The third hole, BD391, was strategically placed between the previous two holes and approximately 30 metres down-dip, intersecting 52.3 g/t gold over 1.69 metres downhole.

These results demonstrate consistent high-grade mineralisation across a 175-metre strike length and 50-metre vertical extent. The mineralised zone remains open along strike and at depth, suggesting significant potential for resource expansion. VP of Exploration and Operational Geology Chris Davis noted: "Given the impressive results and ease of access from existing infrastructure, this discovery is now being prioritised for further drilling in parallel with True Blue."

The structural setting of the new intersections differs from the Brunswick Main lode, being situated within the hinge of an open syncline rather than an anticlinal hinge. This geological variation may indicate additional exploration opportunities within the broader Brunswick system.

Strategic Implications

The Brunswick South discovery arrives as Mandalay approaches completion of its merger with Alkane Resources. This discovery strengthens the combined entity's asset base and provides additional near-term growth opportunities. The timing suggests that Costerfield will contribute enhanced cash flow generation capabilities to the merged organisation.

From an operational perspective, the discovery's location adjacent to existing infrastructure minimises capital requirements for development. The direct access to the Brunswick Processing facility, which concentrates all ore produced at Costerfield, eliminates the need for additional processing infrastructure investment. This operational efficiency translates directly into improved project economics and faster payback periods.

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