St George Mining reports breakthrough results at Mt Alexander

St George Mining Limited (ASX: SGQ) has announced breakthrough exploration results at its flagship Mt Alexander nickel-copper sulphide project in the northeastern Goldfields of WA.

The company reported that MT/AMT survey successfully mapping structures and conductive stratigraphy to a depth of more than 3,000m from surface, has confirmed very significant exploration potential of Mt Alexander project.

SGQ said that new conductive features have been identified at depth within the Investigators, West End, and Fairbridge Prospects in areas yet to be tested by drilling. The company said that potential extensions of the highly mineralised Investigators ultramafic have been identified below the current extent of drilling.

The company reported that conductive structures and stratigraphy parallel to the Cathedrals Belt have been identified on Exploration Licence E39/548, to the north of the Cathedrals Belt.

SGQ announced that the modelling of the MT survey data is continuing with further results due next week. The company said that revised drill programme is being planned to test the new deeper targets.

The company reported that the assays for MAD177 has confirmed high-grade nickel-copper-cobalt-PGE sulphide mineralisation. Significant results include 10.5m @ 4.82% Ni, 1.67% Cu, 0.15% Co and 2.87 total g/t PGEs from 182.5m and include high levels of Palladium and Rhodium. SGQ reported that metallurgical testwork is continuing in Perth.

St George Mining reported that the scoping study for potential mining operation continues to advance, with Phase 2 of environmental study planned for completion in Q2 2020. SGQ said that Entech has been appointed as external geological consultant for the maiden mineral resource estimate for Mt Alexander.

Mt Alexander project

The Mt Alexander Project is located 120km south-southwest of the Agnew-Wiluna belt which hosts numerous world class nickel deposits.

The project is comprised of five granted Exploration Licences, E29/638, E29/548, E29/954, E29/962, and E29/972. The project contains advanced prospects like Investigators (MAD60), Stricklands (MAD71), and Cathedrals (MAD56), which are located on E29/638. 

Mt Alexander has two stand-out EM anomalies named Radar and Bullets prospects. Other unexplored areas in Mt Alexander project include the West End and Fish Hook prospects.

MT/AMT survey at Mt Alexander

The company reported the completion of Magnetotelluric (MT) and Audio-magnetotelluric (AMT) survey at Mt Alexander. This 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.

Encouraging results from MT/AMT survey

The company announced that the interim results from the MT survey have delivered exciting new information on 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.

Investigators Prospect: 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 250m below surface.

The company said that the MT survey data at Investigators indicates that the Investigators ultramafic has been potentially offset by faulting, but that a repetition of the ultramafic occurs below the offset and to the north. This area has never been drilled and could extend to a depth of more than 1,000m.

Other prospects: The company announced that the MT survey data also showed that conductive responses are 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.

Modelling of survey data ongoing

The company announced that the modelling of the MT survey data is continuing with further results expected by early next week.

SGQ said that the processing of the data will include sophisticated 3D inversion modelling, which will provide further definition and accuracy for mapping the stratigraphy and structures.

The company said that the identification of new conductive responses in the MT data provides a strong targeting mechanism to locate additional nickel-copper sulphide deposits.

Drilling deferred

The company announced that the 2020 drill programme will be deferred until all MT survey data is considered and revised drill targets are designed by its technical team.

The company noted that the deferral of the drill programme will also provide an opportunity to plan a programme that addresses the developing restrictions related to the COVID-19 pandemic.

Scoping study update

SGQ reported that it has appointed Entech as its external geological consultant to estimate a maiden JORC-compliant mineral resource at the Mt Alexander Project. SGQ said that the Phase 2 of environmental study planned for completion in Q2 2020.

The company said that the scoping study will focus on assessing a potential mining operation that can be developed with very low capital costs and a simple open-pit mining operation.

Focus on Stricklands deposit

St George Mining said that the resource estimate will initially focus on the Stricklands deposit – where thick massive nickel-copper sulphide mineralisation starts at 30m below surface – and which is considered to have the simplest potential mining operation among the four shallow deposits discovered so far across the Cathedrals Belt.’

Metallurgical testwork

The company reported that the metallurgical testwork with Strategic Metallurgy in Perth is continuing, while the testwork in Canada has been delayed due to travel and other restrictions.

SGQ reported that six diamond holes are planned for Stricklands to provide further samples for ongoing metallurgical testwork.

High-grade assays from MAD177

The company reported that the metallurgical drill hole at Investigators, MAD177, returned assays of 10.5m @ 4.82% Ni, 1.67% Cu, 0.15% Co and 2.87 total g/t PGEs from 182.5m, including 4m @ 7.53% Ni, 2.47% Cu, 0.23% Co and 3.92 total g/t PGEs from 186m.

In addition to high grades of nickel and copper, the mineralisation comprises high-grade platinum group elements with high levels of Palladium and Rhodium – 10.5m @ 2.33g/t Pd and 0.08g/t Rh including 4m @ 3.23g/t Pd and 0.1g/t Rh – which is believed to deliver substantial value in a potential mining operation.

Earthworks completed at Stricklands

The company announced that the earthworks for the resource definition drill programme at Stricklands have been completed and drilling is expected to be concluded within six weeks of commencement.

SGQ said that the start of drilling has been deferred until a decision on the broader drill programme for Mt Alexander is finalised and the implications of the evolving COVID-19 related restrictions are clarified.

Next steps

The company announced that further exploration will be planned based on ongoing drill results, geophysical surveys and geological assessment of prospectivity.

Management comments

St George Mining Executive Chairman, John Prineas said: “The results from the MT survey are a game-changer for exploration at the Mt Alexander Project.

We have already discovered high-grade nickel-copper sulphides at shallow depths across more than 5.5km 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 programme for Mt Alexander and our first exploration results at the new Paterson Project where an airborne magnetic survey was completed this month.

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.

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. The assays for MAD177 have again reminded us of the high quality of our mineralisation.

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.”

Written By Jonathan Norris
Jonathan is a founder of and has been covering the resources industry since 2018. With over 17 years experience in print, broadcast and online media, Jonathan has seen first hand the transformative effect of online niche media.