Hughes Mineral excavated the Mount Sydney project, knowing exactly what they would find. After all, most holes point to VHM.
Fuse Minerals is an Australian exploration company dedicated to identifying the critical mineral resources needed to promote the economy of the future. In late 2024, the team began excavation at the Mount Sydney project, located at the eastern edge of the ancient age Pilbara Craton in Western Australia.
Initial exploration had considered several mineralization styles, but real possibilities began to emerge until the excavation results were analyzed. This could refer to the discovery of large-scale sulfides (VHMS) of important volcanic hosts.
Previous exploration efforts in the region focused on a wide range of quartz veins and returned to encouraging copper, silver, lead and zinc results. However, early gold explorers now reject the area when testing models such as nearby Telfer and iron-copper oxide (IOCG) deposition styles.
Excavation at Bull and Harrison
Two key outlooks, Bull and Harrison, stood out before they excavated. Bulls with the prominent surface mineralization of quartz veins were a natural priority. Meanwhile, Harrison, about 4 km away, featured base metal gossan on volcanic rocks, showing signs of deeper possibilities.
The initial excavation in the bull had disappointing results as the abundant surface veins were unable to continue at depth. However, in Harrison, all six drill holes encountered sulfide mineralization. This is a encouragement sign. More importantly, Harrison’s local geology (riodacito, andesite, basalt, black shale) reflects that of many known VHMS systems.
The presence of iron, copper, and zinc on the fracture surface, coupled with changes in silica cerichite, suggests that the drill hole may have clipped halos outside the VHMS system. The next step was to focus our efforts on Harrison to identify large sulfide zones of high-quality cores.
A tipping point occurred when comparing geochemical assays from bull quartz veins with those from Harrison’s mineralized volcanic rocks. To the team’s surprise, the results showed near perfect alignment. This indicates the possibility of a genetic relationship. Given that Harrison’s mineralized volcanic stratigraphic location is above the bull’s veins, it is logical to interpret these veins as potential feeders of the VHMS system.
Meaning is important. This VHMS system can exceed 15km based on surface mapping, geological continuity, and a series of powerful VTEM (air electromagnetic) conductors. VTEM studies highlight the conductivity enhancement zone, a common tool used in VHMS exploration, often related to sulfide mineralization. One of the most powerful conductors is directly aligned with sulfide-rich rocks drilled in Harrison. Many other conductive targets hosted in the same volcanic sequence remain untested.
Possibility of VHMS in Australia
Globally, VHMS systems are often found in clusters or “camps” where multiple sediments occur at predictable levels of stratigraphy. The Noranda district of Canada is a typical example. This has over 20 deposits, including a large horn No. 5 (150 mt). Canada is famous for its huge Archean-Aged VHMS system. The volcano on Mount Sydney on the date of ~2.75 ga is located in the same geological window known for the prolific VHMS formation.
Australia, like Canada, boasts vast ancient rocks. However, VHMS deposits are discovered here, but so far no match for the size of the Canadian giant. Is it because they don’t exist, or simply because they have not been discovered yet?
Geology of Mount Sydney – Transition from Basalts from Basalts to Mesovolcanoes – Reflecting the classic VHMS hosting sequence. Beyond the 15km strike hosted in favorable stratigraphy, there are multiple untested VTEM targets and early drilling already hit sulfide, so the signs point to something much larger.
Hughes Minerals believes there is a possibility of a camp scale VHMS on Mount Sydney. The hunt is not just for deposits, but for Australian giants.
This article will also be featured in the 22nd edition of Quarterly Publication.
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