St George Mining Ltd (ASX:SGQ) has identified further nickel-copper sulphide targets with potential to expand the large footprint of high-grade mineralisation at Mt Alexander project near Leonora in WA.
Multiple strong conductors have been identified by downhole electromagnetic (DHEM) surveys along the Cathedrals Belt and these are consistent with a massive sulphide source.
This method has proved successful in identifying targets along the belt and this has been backed up by drilling at the Investigators and Stricklands prospects.
St George Mining executive chairman John Prineas said: “It is very pleasing to see the latest exploration work generate new targets for nickel-copper sulphides within the large mineral system at Mt Alexander.
“These targets cover a significant area of the highly mineralised Cathedrals Belt and provide encouragement that the extent of sulphide mineralisation within the belt may be much more expansive than identified by drilling to date.
“Establishing resource base”
“We are continuing along the path of establishing a resource base at Mt Alexander and are excited to be starting our 2019 drill program shortly with such highly prospective targets.”
Drilling to date by St George at the Cathedrals Belt has identified a 4.5-kilometre strike of high-grade nickel-copper sulphide mineralisation.
Large parts of this belt, including extensions to the east and west, remain undrilled and offer highly prospective targets for the discovery of additional nickel-copper sulphides.
Drilling and DHEM surveys are being used concurrently to scope out the scale of the discoveries along the belt.
DHEM surveys were completed earlier this month on a number of diamond drill holes drilled in the December quarter of 2018 at Investigators and Stricklands with off-hole EM anomalies identified.
100% success with method
With a 100% success record of EM conductors in the belt returning mineralised sulphides, the company believes the new targets are likely to be associated with massive sulphide mineralisation and have potential to extend known high-grade mineralisation.
A diamond drilling program to test these conductors will be launched once modelling of the EM data is completed.
A field inspection of the Cathedrals Belt in December 2018 by the company’s technical team has located several new gossans in the area between the Cathedrals and Stricklands prospects untested by drilling.
This area covers a 1,000-metre east-west strike of the Cathedrals Belt and has been named the Fairbridge prospect.
In nickel sulphide exploration, the presence of oxidised nickel-bearing rocks at surface in gossans may represent the surface expression of a nickel sulphide deposit below surface.
Similar gossans drilled at Stricklands and Cathedrals have been confirmed as associated with proximal massive nickel-copper sulphide sources.
Geophysical surveys are underway at Fairbridge to investigate for chargeable material at depth that may represent sulphide mineralisation associated with the gossans.
These include high resolution fixed loop electromagnetic (FLEM) and induced polarisation (IP) surveys.
RC drilling planned
A reverse circulation (RC) drill program is scheduled to begin in mid-February to test the Fairbridge prospect and will employ a two-pronged approach.
Firstly, discrete anomalies modelled from the geophysical data will be drill tested and, secondly, a series of drill holes will be completed as a reconnaissance program using DHEM surveys to further assist in locating mineralisation at depth.
The RC drilling will also test a 2,500-metre strike of the Cathedrals Belt between Investigators prospect and the Ida Fault, named the West End prospect.