St George Mining Limited (ASX: SGQ) is confident that modelling of geophysical data acquired from the recent MT/AMT survey has provided exciting new nickel-copper sulphide targets for the forthcoming drill programme at its flagship Mt Alexander Project, located in the north-eastern Goldfields in Western Australia.
Sophisticated 3D inversion modelling of the initial MT survey data has provided further definition to conductive features identified in that data.
Executive Chairman, John Prineas, said it supports the interpretation that some of these features may represent mafic-ultramafic intrusions with nickel-copper sulphide deposits.
“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,” Mr Prineas said.
“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.
“The deeper conductive zones start at 300m to 500m 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 5.5km 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.
“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 programme.”
The most highly rated new target is a large conductive feature located below and to the north of the shallow high-grade mineralisation already discovered at Investigators – an ideal location for down-plunge extensions of the shallow mineralisation.
The latest modelling suggests that the Investigators ultramafic, which commences at 30m below surface, dips to the north at about 40 degrees and has been dislocated by faulting and granites at approximately 300m below surface.
At approximately 500m below surface and to the north of the shallow mineralisation, a new conductive feature has been detected which could represent the down-plunge continuity of the mineralised Investigators ultramafic.
Two survey lines were completed in the initial MT/AMT survey: an east-west line covering approximately 10km from the West End Prospect in the west to the Bullets Prospect in the east, and a north-south line starting from south of the Investigators Prospect and extending 10km into the northern section of E39/548.
A strong conductive response was recorded by the known shallow mineralisation at Investigators. The conductive response is dislocated by granites and appears again at depth as a large conductive feature.
Significantly, the response at the core of the deep conductive feature has recorded a higher conductivity reading than the known shallow mineralisation.
Air-core drilling will be designed to confirm the presence of ultramafics through recognition of a geochemical signature for those types of rock. This will validate the geological concept and enable more precise targeting for deeper diamond drilling to test the large conductive feature.
The breakthrough results from the initial MT survey warrant an immediate extension of the 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 commenced this week and will be completed in approximately two to three weeks.