Great Divide Mining Restates 169,700 Ounce Gold Resource at Adelong

Resource Restatement Confirms Substantial High-Grade Gold Base

Great Divide Mining Ltd (ASX:GDM) has restated the JORC 2012 Mineral Resources for its Adelong Gold Project in southern New South Wales, consolidating multiple previously prepared estimates by independent consultant GeoRes. The combined resource stands at approximately 1.55 million tonnes grading 3.41 grams per tonne gold, containing 169,700 ounces of gold above a 1.0 g/t cut-off grade. Notably, about 55% of this contained gold is classified in the higher confidence Measured and Indicated categories, providing a solid foundation for the company’s next development phases.

The restatement does not include any new drilling or exploration data by GDM but aggregates prior estimates prepared for former owners, including a September 2022 update for the Caledonian deposit that increased resource confidence. The largest single contributor is the Challenger deposit, with 663,000 tonnes at 3.77 g/t gold for 80,300 ounces, representing nearly half of the total contained gold.

Multiple Deposits Within a Historic, High-Grade Goldfield

The resource spans four deposits: Challenger, Currajong, Caledonian, and Donkey Hill, all situated within the historic Adelong Goldfield. This goldfield has a rich underground mining history, having produced approximately 380,000 ounces of gold from narrow, high-grade quartz veins around the turn of the 20th century. The mineralisation occurs in steeply dipping, north-south striking quartz vein systems hosted mainly within granodiorite, consistent with the geological style that has historically yielded high-grade production.

Modern exploration drilling has predominantly focused on the Challenger and Challenger Extended lodes, with additional drilling at the other deposits. The restated resource provides a consolidated baseline for GDM to prioritize verification work, refine exploration strategies, and advance project studies.

Technical Rigor Underpins Resource Confidence

GeoRes’s restatement relies on extensive historical and modern drilling data collected over decades by multiple previous owners, including reverse circulation, diamond, and rotary air blast drilling. Sampling and assay methods have varied over time, with more recent programs employing rigorous quality control and commercial laboratory analyses. While some historical data have limitations, GeoRes has validated available information and incorporated these factors into resource classification.

The resource estimation employed detailed three-dimensional geological and block modelling techniques tailored to the narrow, sub-vertical vein geometry. Classification into Measured, Indicated, and Inferred categories was based on sample spacing, geological continuity, and data quality assessments. The Caledonian deposit’s 2022 update, featuring closer-spaced drilling and model refinement, notably increased the Indicated portion of its resource.

Implications for Great Divide Mining’s Development Strategy

CEO Justin Haines emphasised that the restatement confirms a substantial, high-grade gold resource at Adelong, with multiple deposits offering opportunities for disciplined technical review and exploration. The consolidated resource base supports GDM’s transition from exploration to development, providing a framework to enhance resource confidence and potentially grow the resource through verification and further exploration.

Given the historical underground workings and the nature of the mineralisation, the resource estimates exclude known stopes where possible but acknowledge that some historical voids may remain unmodelled, particularly at Currajong, Caledonian, and Donkey Hill. The mineral resources are not Ore Reserves, and there is no guarantee of economic extraction, underscoring the importance of upcoming verification and economic studies.

GDM acquired the Adelong tenements through its February 2026 acquisition of Challenger Gold Mines Pty Ltd, consolidating its position in this historically productive goldfield. The restatement aligns with the company’s broader strategy to develop producing assets with established infrastructure and historical mining records.