Redstone Resources (ASX: RDS) has identified deeper and more extensive copper mineralisation in diamond drilling at the Tollu deposit within its West Musgrave project in Western Australia.
Assays confirmed that one of the holes intersected high-grade copper, some 400 metres deeper and 130m to the south of mineralisation discovered at the Chatsworth target within Tollu, with further analysis revealing intersections of significant high-grade copper at two other locations much deeper downhole.
Best assays of 1.8m at 2.5% copper from 912.4m, and 4m at 1.3% copper from 1,048m including 1.6m at 2.7% from 1,048.4m, add to an earlier reported intersection of 10m at 1.37% copper from 193m including 4m at 2.37% from 195m.
Cobalt Sulphide Association
Multiple lower-grade copper intersections were observed throughout the same hole that Redstone believes highlight the potential extent and upside of the copper system at Tollu.
The geochemistry indicated the presence of cobalt in sulphide form – which is not always associated with copper mineralisation – preferentially leached by hydrothermal fluids from a large, massive sulphide accumulation hosted within a mafic magmatic intrusion (such as gabbro) at depth.
Redstone regards this as important to its exploration strategy, providing evidence for a magmatic sulphide source and elevating West Musgrave’s prospectivity for Voisey’s Bay style magmatic copper-nickel-cobalt-platinum group elements (PGE) deposits similar to the world-class NeboBabel discovery, located 60 kilometres to the west of Tollu.
Cobalt mineralisation has been of particular interest to Redstone as it is found in varying amounts with Tollu’s copper mineralisation and has considerable economic value.
Significant Exploration Progress
Chair Richard Homsany said the latest drilling results highlight some of the most significant exploration progress made at West Musgrave.
“This hole has dramatically expanded the known limits of Tollu’s copper mineralisation and suggests it is potentially more extensive and far deeper than previously considered,” he said.
“Analysis of the geochemistry suggests a potential magmatic source for the cobalt, which also gives credence for a similar source for the Tollu copper mineralisation.”
“We are now working towards finalising follow-up drilling plans for early 2026 and will report on further progress in the near-term.”
