Comet Resources Limited (ASX:CRL) has identified numerous additional graphite targets using the results of an aerial electromagnetic survey (EM) over the Springdale Graphite Project in southern Western Australia.
The multiple high-conductivity targets identified are in proximity to the defined Springdale graphite JORC-compliant resource of 15.6 million tonnes at 6% Total Graphitic Carbon (TGC).
As they are also along the clearly defined prospective stratigraphy in the wider licence area, they form high-priority targets for future drill testing.
Comet Resources CEO Philippa Leggat said, “EM has again been demonstrated as a powerful tool for us to target shallow, high-grade graphite mineralisation, increasing the capital efficiency of our exploration.
“The priority targets closest to the shallow, high-grade areas of our existing inferred resources of 2.6 million tonnes at 17.5% TGC is where we will focus.”
A 530.9 line-kilometre helicopter-borne EM survey was completed by CGG Aviation over two blocks in late August 2019 with flight lines flown east-west at 100-metre spacing roughly perpendicular to most of the stratigraphy.
EM Channel 24 image showing priority graphite targets close to existing resource areas, additional stratigraphic targets and recent discovery holes.
Multiple conductive anomalies
This survey clearly defined the outline of the JORC resource and identified multiple conductive graphite bedrock anomalies as high amplitude responses in the late-time EM within the block 1 survey area.
Highest graphite grades defined within the resource correlate to the axis of the North Zone shallow-plunging synclinal fold closure.
This EM survey identified a number of new, similar-looking fold geometries in close proximity to the resource that are untested.
Leggat said, “Our recent diamond drilling program centred on the fold closure in the northern area of the resource.
“The strength of the EM response in this area is interpreted to reflect the relatively shallow, flat-dipping geometry of the high-grade graphite units as seen in previous drilling.
“We are excited to see the new results as they become available over the coming weeks.”
In addition to targets in proximity to existing resources, the survey also delineated numerous new targets within the licence that reflect the folded geometry of the prospective target graphite stratigraphy.
The survey was flown using the HeliTEM 35C2 EM system, which is the only system operating at 6.25Hz base frequency.
This system uses a breakthrough, large-diameter, ultra-low noise receiver and a very-low-frequency, square-wave transmitter pulse, to provide improved detection of high conductance targets.
The low base frequency is also an advantage in areas with high surface conductivities allowing later time conductors to be identified, as successfully demonstrated by this survey.
This survey has again confirmed the ability of the EM system to identify basement graphite targets below conductive cover and is a powerful exploration tool.
With the recent metallurgical program complete and analytical results awaited, Comet will focus on modelling and ranking EM targets for future drilling, with those close to existing resource areas a priority.
Springdale is about 30 kilometres east of Hopetoun in south Western Australia.
The project is on freehold land, with good access to infrastructure being within 150 kilometres of the port at Esperance via sealed roads.