Highlights

  • Tunkillia JORC (2012) Mineral Resource upgraded to 1,500 koz Au (59.5 Mt at 0.78 g/t), following 57,653 metres of infill drilling.
  • Measured and Indicated Resources now total 989 koz Au, including a maiden 151 koz Measured category.
  • Within May 2025 Optimised Scoping Study pit shells, the total gold inventory shows only ±2% variance from earlier estimates, validating the OSS.
  • 81% of mineralisation within the OSS pit shells is now classified as Measured and Indicated.
  • Pre-feasibility Study underway, targeting completion in Q1 calendar year 2027.

Barton Gold Holdings Limited (ASX:BGD) has announced an upgraded JORC (2012) Mineral Resource Estimate (MRE) for its Tunkillia Gold Project in South Australia, following the completion of a substantial infill drilling campaign. The updated resource confirms the geological model underpinning the Company's May 2025 Optimised Scoping Study and provides a more elevated resource confidence base as Barton advances toward a Pre-feasibility Study.

Latest Development

The updated Tunkillia MRE totals 59.5 million tonnes at 0.78 g/t gold for 1,500,000 ounces, with 989,000 ounces classified as Measured and Indicated. This includes a maiden Measured category of 151,000 ounces (5.3 Mt at 0.88 g/t), representing the highest confidence classification available for a gold resource. The upgrade followed 57,653 metres of reverse circulation and diamond drilling across 520 holes targeted within the May 2025 OSS optimised pit shells. Critically, within those pit shells, total gold inventory varies by only ±2% from earlier estimates, and 81% of mineralisation is now Measured or Indicated — a validation of the geological modelling underlying the prior scoping study. The company has also identified a shallow higher-grade Inferred zone within the S1 and S2 pits, estimated to contain 36,000 ounces at 2.04 g/t, as a priority upgrade target.

Company Background

Barton Gold is a South Australian gold developer with four projects in the Gawler Craton: Tunkillia (the flagship with 1.5 Moz Au MRE), Tarcoola, Challenger, and Wudinna. The Company also owns the Central Gawler Mill, the region's only permitted gold processing facility. Tunkillia covers Area 223 and Area 51 within the central Gawler Craton and is located approximately 530 kilometres northwest of Adelaide. The Project has undergone extensive drilling and resource definition work over several decades by prior owners, and Barton has significantly advanced geological understanding since acquiring the asset.

Sector Context

South Australia's Gawler Craton is an emerging gold development jurisdiction, with Tunkillia representing one of the larger undeveloped open-cut gold resources in the country. Proximity to the Company's own gold processing mill at Challenger adds potential Capital efficiency relative to greenfields development scenarios. The OSS modelling for Tunkillia, released in May 2025, outlined a compelling operation with favourable modelled economics, and the upgraded MRE provides the geological foundation for translating that study into a bankable Pre-feasibility Study. The continued development of South Australian gold projects is supported by established Mining legislation and regional government engagement.

Market Perception

The ±2% variance between the updated MRE and the May 2025 OSS resource within the pit shells is an unusually tight reconciliation for a large-scale resource upgrade following extensive infill drilling. This outcome significantly de-risks the PFS process by demonstrating that the geological model is well-calibrated. The maiden Measured category of 151,000 ounces is commercially meaningful for project financing discussions, as the highest-confidence classification is a prerequisite for detailed mine scheduling and lender due diligence. The Company has noted that the Measured classification also supports potential low-dilution funding pathway conversations.

Growth Drivers

Barton has identified several growth catalysts within the Tunkillia portfolio. Outside the OSS pit shells, 6.2 million tonnes at 131,000 ounces of Indicated Resources remain, suggesting that future pit optimisation at higher gold prices may capture additional ounces. Within the OSS pits, the shallow higher-grade Inferred domains (AuHG and POX) provide a focused near-term drilling target for Indicated classification. At Area 51, the northern and southern ends of the deposit showed higher-grade mineralisation continuity, suggesting potential for pit extensions. A silver resource resampling program is also planned, as the current silver estimate — reported only as a subset of the gold resource — is expected to be materially upgraded.

Risks and Challenges

Tunkillia is located in a remote region of South Australia, adding logistical and infrastructure development requirements to any future mining operation. The transition from MRE to Ore Reserves requires a completed PFS incorporating engineering, metallurgical, environmental, and social studies. All modelling to date is based on an assumed open-pit operation and CIL processing, which must be validated through formal PFS-level technical work. The OSS modelling was based on gold prices below current market levels, and while higher prices expand the economic envelope, they also introduce Commodity price sensitivity. Additionally, native title and Aboriginal heritage surveys are ongoing, as is flora and fauna assessment work.

Recent Announcements

The Company has also released an updated Company-wide JORC Mineral Resources Statement, with total gold endowment across all projects now standing at 2.2 million ounces. Barton has separately announced the PFS timeline, targeting Q1 CY2027, with active workstreams including infrastructure studies, heritage surveys, tailings Facility design, and energy assessments. No new information or data has been identified that materially affects information from prior announcements.

Key Insights

Barton Gold has delivered a resource upgrade at Tunkillia that achieves two important outcomes simultaneously: a larger, higher-confidence resource and a tight geological validation of the prior scoping study. With 81% of OSS pit materialisation now Measured or Indicated, 151,000 ounces in the Measured category, and a maiden PFS underway, the Company is positioned to convert a well-modelled resource into a bankable development study. Additional ounce upside from outside the current pit shells and from shallow higher-grade Inferred zones represents further near-term growth potential.