Tommy Burns Project

Overview

The Tommy Burns Project is a historical underground tin and tungsten mine that operated from 1973-1984. Gold Copper Exploration Limited reported production of over 6,000 tonnes of tin and tungsten concentrates from 259,000 tonnes of ore during this period. The mine was closed in 1984 due to the collapse of the tin price, but significant mineralisation remained.

Historical exploration

A substantial body of historical reporting details the exploration work completed by Gold Copper Exploration Limited, which included 96 diamond drill holes and percussion drilling from the surface and from numerous levels within the mine.

Detailed geological work was conducted both underground and on surface. According to one report, the mine contains “several discrete ore bodies ranging in size from 1,000 to 185,000 tonnes.” They range in shape from irregular pods to near-vertical pipes, lenses, veins and elongated bodies; there is significant potential for the discovery of several new ore bodies in the 5,000 to 40,000 tonnes range.

Value capture

Located ~10 km from the main project area, the historic Tommy Burns Mine is the most advanced feeder project of the Dover Castle Project. A 2025 Exploration Target report delineates:

• 2.78 Mt @ 0.36% Sn (10,047 t contained Sn)
• 2,612 t of contained tungsten (W)
• Mineralisation hosted in structurally coherent lodes and a broader metasomatic halo
• Verified by drone-based LiDAR scans and historic underground sampling

Recent studies and exploration have revealed the presence of the critical mineral bismuth at a sufficient grade to represent a unique opportunity for DCM to supplement Tommy Burns’ potential tin mineralisation, and in doing so improve the mine’s future prospectivity.

While the Queensland and Australian governments, as well as the rest of the world, consider bismuth to be a critical mineral, there is currently no known production in Queensland. Tommy Burns could be the first.

The prospect offers near-term resource upgrade potential, with surface and underground access, and multi-commodity endowment (Sn-W-Bi). Planned diamond drilling and stope sampling aim to validate continuity and elevate the asset to JORC classification. Tommy Burns could serve as early-stage feed for plant commissioning or supplement tin production via a modular development approach to the processing plant at the Dover Castle Project.

In parallel, the Sunnymount area hosts several legacy tailings and waste stockpiles, likely derived from earlier processing campaigns. These materials are currently undergoing multi-element sampling and metallurgical characterisation, with a view to assessing residual tin and gold recoveries through modern reprocessing techniques. If successful, these stockpiles may represent a low-capex, high- margin feedstock option for early-stage production or for pilot scale operations.

Strategically, Tommy Burns presents an attractive near-mine development opportunity, combining:

• High-quality geological data
• Existing surface and underground access
• Multi-commodity mineralisation
• Potential early production scenarios