St George Mining Ltd's (ASX:SGQ) modelling of geophysical data from recent survey work has provided new nickel-copper sulphide targets for an upcoming drill program targeting nickel-copper sulphides at Mt Alexander Project, Western Australia.
The company is continuing to unlock the mineral system at its flagship project using magnetotellurics (MT) and audio-magnetotellurics (AMT) surveys.
Sophisticated 3D inversion modelling of the initial MT survey data has provided further definition to conductive features located in positions geologically favourable for nickel-copper sulphides.
St George Mining executive chairman John Prineas said: “The MT survey data is showing us that there is an extensive and deep-reaching structural network at Mt Alexander, which is typical of large nickel sulphide systems.
“We are seeing new conductive zones along strike and down-dip of known nickel-copper sulphide deposits – these locations are very favourable for the potential discovery of additional mineralisation.”
Deeper targets identified
A large conductive feature has been identified below the shallow high-grade deposit at the Investigators prospect and below the current extent of drilling.
Prineas said: “The deeper conductive zones start at 300 metres to 500 metres below surface, so we are still looking at depths that are relatively shallow compared to most current nickel sulphide mines in Western Australia.
“With four shallow, high-grade discoveries across a 5.5-kilometre strike of the Cathedrals Belt, we have always believed that if the system is that long it must also be deeper than the extent of the current discoveries.”
Aircore drilling will be designed to confirm the presence of ultramafics and will enable more precise targeting for deeper diamond drilling to test the large conductive feature.
New nickel-copper sulphide targets have also been identified at depth within the Radar, Cathedrals, Fairbridge and Investigators East Prospects in areas yet to be tested by drilling.
North-south cross section (looking east) of the Investigators Prospect showing MT/AMT 3D inversion modelling of the data
Additional MT survey underway
The company has started an extension of the MT survey to other priority areas along the Cathedrals Belt.
An east-west oriented survey line will extend the east-west traverse across the strike of the Cathedrals Belt from Bullets in the west to the Fish Hook prospect in the east.
Additional north-south survey lines will also be completed across Cathedrals, Fish Hook and West End.
The new survey began this week and will be completed in around two to three weeks.
Drilling program planned
Planning of the drill program for Mt Alexander is being finalised and will start once the additional MT survey in progress is completed.
The multi-rig drill program will prioritise testing of the new conductive zones identified by the MT survey, with drilling to start at Investigators prospect.
Extension and infill drilling of known deposits is planned to test more than 30 electromagnetic (EM) conductors identified in 2019.
Prineas said: “The new MT data increases our confidence that there are more nickel-copper sulphide deposits to be discovered at Mt Alexander.
“We look forward to the start of our upcoming drill program.”
Resource definition drilling of the shallow, high-grade deposit at Stricklands will also be undertaken which, once determined, will be used in the scoping study for a low-cost starter mine at Mt Alexander.