Uncertain Copper Grades at Minnie Springs Prompt Cautious Next Steps for Augustus

Drilling Program Overview

Augustus Minerals Limited (ASX: AUG) has announced the results from its recent deep diamond drilling program at the Minnie Springs prospect, part of the expansive 3,600km² Ti-Tree Project located in Western Australia's Gascoyne Region. Supported by a $110,000 grant from the Western Australian Government’s Exploration Incentive Scheme (EIS), the program aimed to test the geological and mineralisation framework of a large copper-molybdenum porphyry system.

Key Assay Results and Geological Insights

The highlight drill hole, MSD010, reached a depth of 600.3 metres and intersected multiple zones of molybdenum and copper mineralisation. Notably, the hole returned intervals including 5 metres at 322ppm molybdenum from 222 metres, 6 metres at 450ppm molybdenum from 340 metres, and a significant 6 metres at 433ppm molybdenum and 1,001ppm copper from 356 metres. These results confirm the presence of mineralisation consistent with a classic porphyry copper-molybdenum system, characterised by potassic altered leucogranite transitioning into phyllic altered granodiorite and propylitic altered granite.

The mineralisation styles observed include disseminated molybdenite within the rock matrix, quartz vein-hosted molybdenite, and coatings within chlorite-filled shear fractures, all associated with pyrite. The copper mineralisation, while present, was thinner and of lower grade than hoped near the boundary of the potassic and phyllic zones, suggesting either the need for deeper drilling or a possible absence of higher-grade copper zones at this location.

Interpretation and Next Steps

Compared to historic drilling by previous explorers, which recorded higher-grade molybdenum intervals (such as 60m at 640ppm Mo), the current hole’s lower grades imply a plunge component to the higher-grade mineralisation. This suggests that the mineralised zones may extend at depth or along strike in a plunging orientation, a hypothesis that will be tested through further geological modelling.

Drilling of the second planned hole under the EIS grant has been placed on hold pending a comprehensive review of the MSD010 results. This cautious approach reflects the company’s commitment to refining its understanding of the system before committing additional capital to further drilling.

Strategic Context and Project Potential

The Ti-Tree Project, with its extensive tenure and diverse mineralisation potential, including copper, gold, lithium, uranium, and rare earth elements, remains a cornerstone of Augustus Minerals’ exploration strategy. The Minnie Springs prospect, in particular, offers a compelling target given its geological setting within the Capricorn Orogen and the Ti Tree Shear Zone, a major structural corridor known for hosting mineral deposits.

Augustus Minerals’ leadership team, with significant experience in exploration and mine development, is well-positioned to advance the project through systematic exploration and resource definition. The support from the WA Government’s EIS program underscores the strategic importance of this region for critical minerals exploration.