Resource Upgrade Tightens Grade Model but Lowers Indicated Proportion at Plum Pudding

Resource Upgrade Highlights

Aurumin Limited (ASX: AUN) has reported a 33% uplift in its Plum Pudding gold resource, adding 4,600 ounces to bring the total to 18,700 ounces. This increase forms part of the broader Sandstone Operations resource, which now stands at an impressive 951,000 ounces of gold. The upgrade follows a successful reverse circulation (RC) drilling campaign completed in late 2024 at the Central Sandstone Project, located approximately 520 kilometres northeast of Perth.

Drilling Results and Geological Context

The recent drilling at Plum Pudding has reinforced the existing geological interpretation of a sub-vertical zone of quartz stockwork and shear vein arrays hosted within sheared ultramafic rocks. Notably, the drilling targeted extensions around a previously reported bonanza intercept of 18 metres at 25.8 grams per tonne gold. While no new bonanza zones were discovered, the results align well with the global resource grade, confirming the NNW-striking shear corridor as the primary control on mineralisation.

At the Shillington deposit, drilling focused on resource extension and infill within the current open pit footprint. The assays to date support the existing geological model, with several intercepts showing moderate gold grades, such as 14 metres at 1.3 grams per tonne and 6 metres at 1.8 grams per tonne. However, the Shillington BIF target yielded lower grades, indicating limited impact on the current resource estimate.

Technical and Operational Insights

The resource update incorporates a tightening of wireframing parameters and an increase in top cut grades from 15 to 30 grams per tonne, reflecting the influence of high-grade samples from recent drilling. The proportion of indicated material has decreased slightly, but total contained gold has increased, suggesting a higher confidence in the grade model despite a reduction in volume.

Mining assumptions remain conventional open pit methods, with no modifying factors applied yet to dilution or recovery. Metallurgical test work indicates a gravity recoverable gold average of 60% and a gold extraction recovery of 92.4% at 75 microns, supporting the economic viability of the deposit.

Strategic Outlook and Next Steps

Managing Director Daniel Raihani emphasised the company’s focus on building critical mass for future gold production. Aurumin is progressing with the integration of recent drilling data into updated resource models, with a Shillington resource update expected in the current quarter. Additionally, the company plans to commence drilling targeting iron ore at Sandstone, aiming to leverage the project's multi-commodity potential.

The Central Sandstone Project benefits from existing infrastructure, including a 500,000 tonnes per annum CIL processing plant (requiring refurbishment), permitted tailings storage, bore fields, and camp facilities, positioning Aurumin well for advancing towards production.