ASX listed nickel explorer St George Mining has continued to intersect encouraging intersections of massive and disseminated nickel-copper sulphide mineralisation at its developing Investigators prospect, located near Leonora in the north-eastern Goldfields of WA.
The latest diamond drilling program is targeting down dip and down plunge extensions of the identified mineralisation, which is delineated by a very large conductive EM signature over at least 1.5km of east-west strike at the prospect.
The company believes that the drill intersections recorded to date at Investigators do not fully account for the size and strength of the EM anomaly there, strongly suggesting the potential for the discovery of further, thicker massive sulphide mineralisation in the area.
Recent drilling intersected wider massive sulphide intercepts in the order of true widths between about 5-6 metres.
That mineralisation is contained within prospective rock sequences of the sought-after mafic-ultramafic units, which are the main hosts to the mineralisation at the broader Mt Alexander project.
According to St George, portable XRF analyses of the recently drilled cores have turned up exceptional high grade numbers, averaging between 8.0 - 8.8% nickel and 4.5 – 5.0% copper in the massive sulphide intersections.
Laboratory assays are expected from these sections of mineralised core shortly and will be reported when they become available.
The geology of these latest mineralised intersections at Investigators are logged as mafic-ultramafic rock sequences, sandwiched between unmineralised granitoid.
This recent drilling confirms a 200m down-dip extension of the mineralisation defined in this section of the Investigators prospect.
According to the company, the new intersections are supported by strong down-hole geophysical electromagnetic conductors located both up-dip and down-plunge, pointing the way towards further extensions of the high grade zone.
St George has been very successful targeting off-hole EM anomalies at Mt Alexander for extensions to the nickel-copper mineralisation and many areas remain open and undrilled at this stage.
The company’s Executive Chairman, John Prineas said: “MAD126 and MAD127 intersected thick massive sulphides at Investigators with outstanding preliminary XRF values for nickel and copper. Laboratory assays are expected shortly.”
“Additional intersections of nickel-copper sulphides have now confirmed extensions to the mineralised ultramafic both laterally and at depth in the northerly down dip direction.”
The broader Mt Alexander project is centred on the Ida fault zone, about 120km south-southwest of the highly endowed Agnew-Wiluna greenstone belt that hosts numerous world-class nickel deposits.
The Investigators prospect lies at the western end of a 3.5km long east-west trending mineralised corridor that defines the high-grade nickel-copper system being explored by the company and also incorporates the Stricklands and Cathedrals prospects.
Recently, St George has concentrated its exploratory drilling programs solely on the Investigators ore system, which it says is the largest of the three discoveries it has made at the Mt Alexander project to date.
Although the sulphide accumulations have relatively modest widths, the company has employed the use of DHEM surveying to great effect, targeting ore grade intercepts thus far at all three prospects.
The complex nature of the massive nickel-copper mineralisation at Mt Alexander has St George drawing parallels with the other WA deposits including the Flying Fox mine in the Forrestania Belt and the Silver Swan mine, north of Kalgoorlie.
These deposits have a significant structural geology control on the positioning of high grade mineralisation, which the company believes is not dissimilar to its discoveries at the Mt Alexander project.
What is very clear to St George management, is that the company has found something pretty interesting at Investigators with the high grade mineralisation starting right from surface.
This throws up the possibility of extracting the high value economic nickel-copper ores via a low-cost open pit starter operation, a rare beast indeed in the 21st Century.
Factor in the cobalt and platinum group element credits from the Mt Alexander ores and the outlook becomes even more favourable.
By Matt Birney
