More outstanding nickel-copper sulphide targets at Mt Alexander
Emerging Western Australian nickel company St George Mining Limited has announced further nickel-copper sulphide targets at the Mt Alexander Project.
The project, located near Leonora in the North Eastern Goldfields, has the potential to significantly expand the large footprint of high-grade mineralisation at the Project.
Drilling to date by St George at the Cathedrals Belt has identified a 4.5km strike of high-grade nickel-copper sulphide mineralisation. Large parts of the Cathedrals Belt, including extensions to the east and west of the known mineralisation, remain undrilled and offer highly prospective targets for the discovery of additional nickel-copper sulphides.
St George Mining Executive Chairman, John Prineas said: “It is very pleasing to see the latest exploration work generate new targets for nickel-copper sulphides within the large mineral system at Mt Alexander.
“These targets cover a significant area of the highly mineralised Cathedrals Belt and provide encouragement that the extent of sulphide mineralisation within the Belt may be much more expansive than identified by drilling to date.
“We are continuing along the path of establishing a resource base at Mt Alexander and are excited to be starting our 2019 drill programme shortly with such highly prospective targets.”
Drilling and DHEM surveys are being used concurrently to successfully scope out the scale of the discoveries along the Cathedrals Belt.
DHEM surveys were completed earlier this month on a number of the diamond drill holes drilled in the last quarter of 2018 at the Investigators and Stricklands Prospects. Off-hole EM anomalies were identified from the surveys in several of the drill holes.
With a 100% success record of EM conductors in the Cathedrals Belt returning mineralised sulphides, we believe these new targets are likely to be associated with massive sulphide mineralisation and have excellent potential to further extend the known high-grade mineralisation in the Cathedrals Belt.
A diamond drill programme to test these conductors will be launched once modelling of the EM data is completed.
A reconnaissance field inspection of the Cathedrals Belt in December 2018 by the Company’s technical team has located several new gossans in the area between the Cathedrals and Stricklands Prospects. This area covers a 1,000m east-west strike of the Cathedrals Belt and has been named the Fairbridge Prospect.
Gossans are weathered or decomposed rock located at the surface and may represent the upper and exposed part of an ore deposit at depth. In nickel sulphide exploration, the presence of oxidised nickel bearing rocks at the surface may represent the surface expression of a nickel sulphide deposit below the surface.
Similar gossans drilled at the Stricklands and Cathedrals Prospects have been confirmed as associated with proximal massive nickel-copper sulphide sources. Geophysical surveys are underway at Fairbridge to investigate for chargeable material at depth that may represent sulphide mineralisation associated with the gossans.
The first surveys to be completed will be high resolution fixed loop electromagnetic (FLEM) and induced polarisation (IP) surveys. Only a small part of the target area has been surveyed so far. Early data indicates a large anomaly over more than 100m in strike situated immediately to the west of the Cathedrals Prospect. Further details will be announced as the new data is acquired and interpreted.
The earlier SAMSON EM survey completed over this area identified several weak EM responses. However, the SAMSON survey may not have been ideally configured to test this area for mineralisation at depth.
Drill hole MAD104 at Stricklands intersected more than 6m of sulphide mineralisation that was not detected by ground-based EM surveys. This supports the potential for massive sulphides to be present along the Cathedrals Belt notwithstanding the absence of a strong EM signature from surface EM surveys.
An RC drill programme is scheduled to commence in mid-February 2019 to test the Fairbridge Prospect and will employ a two-pronged approach. Firstly, discrete anomalies modelled from the geophysical data will be drill tested. Secondly, a series of drill holes will be completed as a reconnaissance programme using DHEM surveys to further assist in locating any mineralisation at depth.
Further details of the drill programme will be announced soon, once the geophysical surveys are completed and the new targets are modelled and interpreted by Newexco and the Company’s technical team.
The drilling completed in 2018 at the Investigators Prospect has provided substantial new data on the orientation of the Investigators ultramafic unit. Further interpretation of this data by St George’s technical team suggests that the unit dips to the north-west and may lie underneath a paleochannel which is observed in the magnetic data.
The paleochannel is likely to have interfered with the effectiveness of the surface EM survey completed in this area, suggesting that a significant and prospective portion of the western strike of the highly mineralised Cathedrals Belt remains underexplored.
A line of wide-spaced holes will be planned for the West End Prospect – over a 2.5km strike from Investigators to the Ida Fault in the west. DHEM surveys will be completed in the drill holes to further investigate for sulphide mineralisation at depth.