Nickel company St George Mining (ASX: SGQ) has discovered high-grade nickel-copper sulphides in an unexplored section of the Cathedrals Belt, within its flagship Mt Alexander project in WA’s north-eastern goldfields.
A maiden drillhole at the newly-named Radar prospect intersected nickel-copper sulphide mineralisation between 44.2m and 51.7m downhole, including intervals of massive nickel-copper sulphides.
The hole was drilled to test a new electromagnetic conductor detected last month by a moving loop EM (MLEM) survey over a 2.2km east-west strike of the Belt.
An optimised fixed loop EM survey confirmed a late-time anomaly, which was modelled with a conductivity of 35,000 Siemens at a depth of approximately 50m.
A downhole EM survey will be completed to identify extensions of mineralisation around the hole and to plan follow-up drilling.
St George said the new discovery presents an opportunity to drill out a new high-grade prospect which – when combined with the advanced Investigators, Stricklands and Cathedrals prospects – could add substantial volumes of mineralisation to a potential resource at Mt Alexander.
It also confirms the prospectivity of unexplored areas of the Cathedrals Belt for further high-grade mineralisation, in particular the West End and Fish Hook prospects located on the western and eastern extensions of the Belt.
Executive chairman John Prineas believes the increased strike of high-grade mineralisation along the Cathedrals Belt is indicative of a large mineral system.
“The discovery of high-grade nickel-copper sulphides in an area with about 10m of transported overburden and more than 1km from the nearest known mineralisation on the Cathedrals Belt is an excellent exploration result and a credit to our technical team,” he said.
“The occurrence of high-grade nickel and copper sulphide mineralisation at shallow depths is rare and we are delighted to have further extended the strike of this type of mineralisation along the Cathedrals Belt to an impressive 5.5km.”
Last month’s MLEM survey was completed over a 2.2km east-west strike of the Cathedrals Belt – from the Cathedrals prospect in the west to the Bullets prospect in the east – and identified two stand-out EM anomalies.
One has been named Radar and is the location of the nickel-copper sulphides discovery.
The other anomaly is located at Bullets, along strike from a historical drill intersection of nickel-copper sulphides made by BHP and co-incident with a larger magnetic feature.
Drilling at Bullets is scheduled to begin next week.
Fish Hook prospect
A small MLEM survey has also been completed at Fish Hook over a highly-prospective area identified by an initial soil survey which recorded a strong nickel-copper anomaly co-incident with a magnetic feature interpreted to represent mineralised ultramafics.
St George said the Fish Hook area has about 10m of sand cover and appears to be geologically-similar to Radar with the same linear magnetic features.
“In light of our drilling success at Radar, the EM anomalies at Fish Hook are emerging as very exciting drill targets,” Mr Prineas said.
“We have commenced a comprehensive soil survey at Fish Hook which will cover the entire 8km east-west strike length of the Cathedrals Belt east of Bullets and will be followed by a MLEM survey with particular focus on areas of nickel-copper soil anomalies.”
St George has submitted an updated program of works for the Mt Alexander project to the Department of Mines which incorporates drilling at Fish Hook and the emerging EM targets.
The company expects approval by mid-October.
Comprising five granted exploration licences, the Mt Alexander project is located 120km south-southwest of the Agnew-Wiluna greenstone belt in WA’s Yilgarn Craton, home to numerous world-class nickel deposits.
The Cathedrals, Stricklands and Investigators nickel-copper-cobalt-PGE discoveries are located on the E29/638 licence held in joint venture by St George (75%) and Western Areas (ASX: WSA), with St George as manager.
Western Areas retains a 25% non-contributing interest in the licence until there is a decision to mine.
Last month, Western Areas forecast a positive future for nickel in its full-year report to shareholders.
At mid-morning, shares in St George were trading 21.43% higher at $0.17.
Shares in Western Areas were up 11.69% to $2.77.