Taruga Minerals may have a tiger by the tail in South Australia, with geophysical surveys showing the company’s Wyacca copper discovery could extend along more than seven kilometres of strike. Recent drilling at Wyacca has delivered a string of shallow high-grade copper intercepts such as 5 metres at 2.4 per cent copper, including 1m at 9.5 per cent copper from just 17m down-hole.
The company is now expanding the copper hunt across its Mt Craig tenure, about 600km north of Adelaide, with a detailed review of historical datasets from across the project area highlighting 15km of prospective stratigraphy that appears ripe for testing.
The acquisition and review of historical EM data has provided invaluable data which will assist us with drill targeting at the Wyacca high-grade copper discovery. While the IP survey only extended for 1.7km along strike at Wyacca, the VTEM data extends for approximately 15km along strike at the top of the Mt Craig Project, covering the entire Wyacca, and penetrates for greater depths than the IP survey, highlighting further down-dip extensions of the host Tindelpina Shale.
The combined review of the VTEM data and historical government mapping confirms a 15km continuous strike of the host Tindelpina Shale, both east and west along strike from Wyacca, where only limited drilling has been conducted over 900m of strike to date.
Mt Craig has a long history of copper production, with small-scale operations being developed at Wyacca back in the 1860s. Old mine records show a near-surface, high-grade core to the copper discovery produced at an astonishing average head grade of 40 per cent copper. As mining progressed in later years, across a series of shafts and small pits, this grade dropped to a still very healthy 3 per cent copper before a falling copper price curtailed operations.
However, with the red metal now hovering around US$10,000/t and most commercial mines around the world mining ores grading at 1 per cent copper or less, Taruga may be riding a winner at Wyacca.
Geologically, management says its review of the copper-rich prospect is showing all the characteristics to host a large mineralised system including host rocks over an extensive strike length, a supportive underlying structural architecture and geophysics hinting at an extensive mineralised envelope.
Previously, historical mining and exploration had only pinned down Wyacca over little more than a kilometre of strike, however a recent review of the geophysical datasets has blown out the potential size of the discovery to over 7km of strike. A limited induced polarisation, or “IP” survey left the core of the system open along more than 1.7km of strike, whilst airborne electromagnetics, or “EM” has outlined responses along a whopping 7km of the stratigraphy, with several responses indicating the potential for high-grade chalcopyrite-bornite-rich feeder zones at depth.
The early-time VTEM anomaly, which represents shallow depth responses, is coincident with the IP anomaly, where the locations of the recently returned high-grade drill intercepts show up as hot zones at these shallow depths. The anomaly response intensifies in the mid-time VTEM image, in the down-dip direction of the Tindelpina Shale along the entire 7km strike and may reflect an increase in the anomaly signal at depth.
Interestingly, these surveys appear to have only tested around half of the copper-rich sediment package, leaving the company with plenty of racetrack to cover in the months ahead.
The company is now planning broader-scale exploration across the Mt Craig tenure with three-dimensional modelling of the airborne EM underway to be supplemented with down-hole EM and IP as drilling continues across the Wyacca targets. The modelling will allow the company to rank the sulphide targets across the extensive strike length of the discovery and better prioritise ongoing drilling.
With extensive target stratigraphy identified at Mt Craig and the copper price currently off and racing, Taruga may be riding a winner as it works to uncover a new major copper discovery in South Australia.
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