This is a Western Australian copper-nickel-cobalt project being undertaken by the Yamarna Joint Venture with Great Boulder having the right to earn a 75% interest.
This would require the company to fund $2 million in exploration over a five-year period.
Right address for promising results
The project is in a highly prospective area, only 30 kilometres west of the Gruyere gold deposit in the Eastern Goldfields district of Western Australia.
The Yamarna project hosts the southern section of the Mount Venn Igneous Complex.
This is a layered mafic-ultramafic complex within which historical exploration to the north has returned anomalous values for nickel and copper.
Identification of multiple conductors
The potential discovery of a feeder structure within the Mt Venn project is important as many globally-significant magmatic nickel sulphide ore bodies occur within these structures.
From a geological perspective, this is where nickel-rich magma first mixes with sulphur to produce massive sulphide deposits.
Hence, the identification of multiple conductors over a 6-kilometre strike through an airborne electromagnetic (EM) survey of the Eastern Mafic complex at Mt Venn was well received.
Mineralisation open in every direction
The Eastern Mafic complex sits next to the Mt Venn discovery, where copper, nickel and cobalt mineralisation has been identified over several kilometres of strike.
Mineralisation at Mt Venn, which remains open in every direction, is copper dominant and indicative of late-stage formation within the intrusion.
Preliminary XRF analysis of aircore drilling over the Eastern Mafic complex has demonstrated anomalous copper and nickel coincident with the airborne EM conductors.
Confirms potential for massive sulphide mineralisation
Great Boulder managing director Stefan Murphy said: “We have identified over 25 discrete, late-time conductors located in a part of the intrusion previously identified as having elevated copper, nickel and cobalt.
“This geochemical anomalism has been confirmed with preliminary XRF field assays, extending the copper-nickel-cobalt footprint to over 4 kilometres in the core of the intrusion and even further along the eastern shear zone.”
These results support Great Boulder’s view that the Eastern Mafic complex has the potential to host significant massive sulphide mineralisation.
A detailed ground MLEM (moving loop electromagnetic) survey will now commence on the strongest conductors within the Eastern Mafic complex.
MLEM is increasingly being used in areas where there are large tracts of territory to be covered and where there is a particular interest in identifying deeper mineralisation.
Significantly, MLEM was successfully used by Great Boulder to identify conductor plates at Mt Venn which subsequently returned promising zones of sulphide mineralisation.
Identifying deeper mineralisation
A paleochannel that cuts the western side of the Eastern Mafic complex has resulted in a wide paleo ‘valley’ with significantly deeper weathering that could mask bedrock conductors.
A wide spaced 200-metre line by 100-metre station MLEM survey will be completed over this area in order to detect anomalies beneath the conductive cover.
The results from this surveying could be extremely significant in helping to determine the possible size of the resource and shaping the company’s ongoing exploration strategy.
Important news flow from Jundee South
There is also the prospect of near-term positive news in relation to Great Boulder’s Jundee South project, most of which has been subject to limited previous exploration.
Prospectivity of the Jundee South project is further enhanced by Northern Star’s (ASX:NST) ongoing exploration success within its nearby Jundee operations.
The company has made new discoveries at this project and these are being made within the Jundee Dolerite and broader Yandal greenstone belt.
The proximity of the projects can be seen below.
During the March quarter, Great Boulder undertook auger geochemistry to test for gold anomalism associated with the Jundee Dolerite on its tenement.
Final assay results are expected shortly, after which Great Boulder will plan follow-up aircore drilling to test surface gold anomalies detected from first-pass auger sampling.