ASX-listed nickel explorer, Estrella Resources has recently completed an “experimental” seismic survey over the major basal contact at its Carr Boyd nickel project about 80km north-north-east of Kalgoorlie.
The Perth-based company described the survey as a necessary de-risking tool it says will increase the success rate of deeper drilling targeting the basal contact for nickel sulphides.
Estrella has also recently finished phase two diamond drilling at the T5 discovery area. To date, 15 holes have been sunk into the exciting T5 prospect for an aggregate drilling coverage of about 7,660 metres.
The stand-out nickel sulphide hit from the latest round of diamond drilling was 20.1m at an average grade of 1.04 per cent nickel and 0.67 per cent copper from 368.5m down-hole.
Within that wide intersection was a higher-grade core of 2.45m grading 1.65 per cent nickel and 2.01 per cent copper, 5.88m at 1.39 per cent nickel and 0.66 per cent copper, and 2.1m at 1.37 per cent nickel and 0.54 per cent copper.
Other notable intercepts were 13.9m going 1.18 per cent nickel from 431.6m depth including 3.2m at 3.19 per cent nickel and 0.64 per cent copper from 436.3m, and 4.9m at 0.96 per cent nickel from a whopping 603.7m depth including 1.71m at 1.63 per cent nickel and 0.66 per cent copper.
According to Estrella, the drilling points to the T5 prospect being a feeder zone along which sulphides have travelled.
The company says the next round of infill and step-out drilling has kicked off and will test the T5 contact to the north and south of known mineralisation in order to expand the zone laterally.
Interestingly, down-hole electromagnetic survey data received by Estrella shows the T5 conductor continuing to increase with depth.
Deeper drilling will be planned once results of the seismic survey have been fully interpreted and small-scale faulting of the contact has been considered, the company says.
Two diamond holes were also recently drilled to gather geological data in support of the seismic modelling and to confirm the position of the basal contact.
The seismic program featured a new type of low-impact vibrator called an e-Vibe, operated by Ultramag and was the first time the system in tandem with new seismic nodes from Schlumberger was deployed in a hard-rock, Archean nickel environment, according to Estrella.
Estrella says the compact seismic source allowed it to access areas previously inaccessible to conventional seismic machinery due to its cost, size and environmental impact. As a result, it enabled the company to image the prospective basal contact at depth ahead of drill planning.
Estrella Resources Managing Director, Chris Daws said: “The experimental seismic program was completed successfully and the initial results are promising, which should allow our geologists to see the basal contact at depth for the very first time.”
“Combined with the regional mapping works and the drill rig which continues to uncover mineralisation at our flagship Carr Boyd nickel and copper project, we are continuing to work at full stride so that we can unlock the source of the nickel and copper sulphides discovered to date at the project.”
Ultramag carried out a 20-linear-kilometre seismic acquisition process. A couple of months of data processing and interpretation will now follow before Estrella has a full 3D interpretation of T5 and the embayment area.
The company explains the variable dipping and faulted nature of the Carr Boyd basal contact, which it describes as the most prospective horizon within the intrusive complex, has historically been difficult to pinpoint by drilling. Utilising seismic will help improve the prospects of drilling at significant depths, it says.
Estrella says the hard-rock seismic project will qualify for an R&D rebate.
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By Matt Birney
