THE DRILL SERGEANT: St George Mining (ASX: SGQ) has identified a raft of new exploration targets at the company’s Mt Alexander nickel-copper sulphide project in the north-eastern Goldfields of Western Australia.
St George Mining completed an MT/AMT survey at Mt Alexander that was designed to map structures and conductive rock types (including mafic/ultramafic intrusives) along two key sections of the Cathedrals Belt that are known to host nickel-copper sulphide mineralisation.
The survey was also designed to identify repetitions of similar structures and stratigraphy in the underexplored tenements adjacent to the Cathedrals Belt.
The company reported that the interim results from the MT survey have indicated the presence and orientation of the prospective structures and potential mafic/ultramafic stratigraphy, opening up a new range of priority targets for nickel-copper sulphides.
At the Investigators prospect, data from the MT survey has clearly shown a conductive response that is coincident with the Investigators ultramafic where extensive high-grade mineralisation has already been discovered from near surface to more than 250 metres below surface.
The MT survey data also demonstrated conductive responses to be present at depth at the Fairbridge prospect, the West End prospect and to the north of Investigators on tenement E39/548 (owned 100% by St George).
These areas have also never been drilled.
“The results from the MT survey are a game-changer for exploration at the Mt Alexander project,” St George Mining executive chairman John Prineas said in the company’s announcement to the Australian Securities Exchange.
“We have already discovered high-grade nickel-copper sulphides at shallow depths across more than 5.5 kilometres of the Cathedrals Belt.
“However, intrusive mineral systems like we have at the Cathedrals Belt will typically have significant mineralisation at depth.
“These potential larger deposits are likely to be at deeper levels than explored to date at the Cathedrals Belt and our challenge has been how to best target drilling to discover these deeper, undercover deposits.
“The MT survey has gone a long way towards unlocking the geological model at the Cathedrals Belt by providing new and breakthrough insights into the stratigraphy and structural framework at depth.
“We now have a guide to where the granites have disrupted the ultramafics, how the ultramafics have been folded and – most importantly – where the deeper deposits may be located.
“We will revise the drill programme for Mt Alexander in light of this data and are very excited at the opportunity to test drill these new targets.
“The COVID-19 pandemic has created many challenges for our community and for our industry.
“We will carefully navigate this evolving period of uncertainty to protect the health and safety of our team and service providers, and to keep St George strong.
“We are undeterred in our commitment to deliver further exploration success at our projects and will be announcing more significant exploration initiatives over the coming weeks, including a revised drill program for Mt Alexander and our first exploration results at the new Paterson project where an airborne magnetic survey was completed this month.”
St George also announced the appointment of Entech as its external geological consultant to estimate a maiden JORC-compliant mineral resource at the Mt Alexander project.
A scoping study is scheduled that will focus on assessing a potential mining operation that can be developed with very low capital costs and a simple open-pit mining operation.
The resource estimate will initially focus on the Stricklands deposit – where thick massive nickel-copper sulphide mineralisation starts at 30m below surface.
St George considers Strickland to have the simplest potential mining operation among the four shallow deposits discovered so far across the Cathedrals Belt.
“The appointment of external geological consultants for a maiden resource estimate is another major step in the scoping study for the potential mining of the shallow deposits at the Cathedrals Belt,” Prineas continued.
“We are aiming to deliver an economically robust start-up mine with very low up-front capital costs and a high-value product with exceptional payabilities for nickel, copper, cobalt and platinum group metals that include palladium, platinum and rhodium.”
From the drill bit, St George received assays for drill hole MAD177, which it declared to have confirmed high-grade nickel-copper-cobalt-PGE sulphide mineralisation, including:
10.5 metres at 4.82 per cent nickel, 1.67 per cent copper, 0.15 per cent cobalt and 2.87 total grasm per tonne PGEs from 182.5m, including 4m at 7.53 per cent, 2.47 per cent copper, 0.23 per cent cobalt and 3.92 total g/t PGEs from 186m.
Platinum group metals include high levels of Palladium and Rhodium – 10.5m at 2.33g/t Pd and 0.08g/t Rh, including 4m at 3.23g/t Pd and 0.1g/t Rh.
“The assays for MAD177 have again reminded us of the high quality of our mineralisation,” Prineas said.
“Long-term market demand for new high-grade nickel sulphide discoveries like Mt Alexander remains very strong and St George is exceptionally well positioned to take advantage of the economic bounce-back when the pandemic subsides.”