Great Western EM survey adds groove to Thunder’s DeGrussa vibe
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Excitement levels are building at Great Western’s Thunder target, which appears similar to Sandfire Resources’ high-grade DeGrussa VMS copper-gold project about 112km northeast.
This is thanks to a moving loop electromagnetic survey identifying a large, potentially company-making, EM anomaly that has been defined over 800m in length from a depth of just 100m.
More importantly, this anomaly is directly adjacent to a 1.7km long copper-gold soil anomaly that is interpreted to sit within a setting of shales and siltstones intruded by mafic volcanic dykes and adjacent to the intersection of two large faults.
Thunder was first identified by Great Western Exploration (ASX:GTE) as a DeGrussa analogue in May this year, after soil sampling identified two large areas of anomalous copper-gold covering about 4sqkm that includes the aforementioned copper-gold soil anomaly.
These areas are coincident with a number of dolerite dykes intruding the Yerrida Proterozoic rocks, which consist of siltstones and shales of the Maraloou formation.
The base of the Maraloou formation is also intercalated with basalts that are the ideal setting for DeGrussa-style volcanogenic massive sulphide (VMS) mineralisation.
DeGrussa is thought to have formed from the intrusion of dolerite and basalts into poorly consolidated and saturated Proterozoic sediments, similar to those found at Thunder.
With over $5M in the bank at the end of the June Quarter and a very supportive share registry, Great Western are well funded to continue with their high impact exploration across their significant (>5,000 sqkm) tenure.
The potential of finding a deposit similar to Sandfire Resources’ (ASX:SFR) flagship is certainly exciting, given that it had an ore reserve of 8.39 million tonnes grading 5.6% copper and 1.8 grams per tonne (g/t) gold in its June 2011 definitive feasibility study.
Development was completed in 2012 and DeGrussa has been producing since then from the original deposit and satellite mines with Sandfire recording output of 70,845t of copper in the 2021 financial year.
Recent drilling by DGO Gold (ASX:DGO) at the Yerrida project around 75km south of Degrussa has also generated exploration interest in the region of late.
Earlier this month DGO hit a 39m zone from 295m in its maiden diamond hole at Yerrida which included bands of sulphide mineralisation, including 1.8m of semi-massive pyrrhotite-pyrite and disseminated chalcopyrite.
That hole was testing a target within a broader 10km zone of airborne electromagnetic anomalies coincident with an 8km long magnetic anomaly.
Thunder is located within Great Western’s Copper Ridge project, in the southern portion of the Yerrida basin.
Given the company-making nature of DeGrussa and the exploration activity nearby, it is not hard to see why Great Western is eager to start spinning the drill bit with planning for an initial drill program now underway.
This article was developed in collaboration with Great Western Exploration, a Stockhead advertiser at the time of publishing.
This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.