St George Mining Ltd (ASX:SGQ) (FRA:S0G) expects to begin diamond drilling of new electromagnetic (EM) conductors next quarter at its flagship Mt Alexander nickel-copper sulphide project in the north-eastern Goldfields of Western Australia.
DHEM surveys in drill holes MAD185, MAD192 and MAD193 have identified a total of 11 off-hole EM anomalies for follow-up testing.
Each of these holes intersected disseminated nickel-copper sulphides on the basal contact of the same mafic-ultramafic intrusive unit - a positive indication for the potential presence of massive nickel-copper sulphides along strike from these holes.
The first two targets to be drilled in 2021 will be the strongest of the off-hole conductors identified from surveys in MAD192 and MAD185.
“Many milestones achieved ”
St George Mining executive chairman John Prineas said: “Notwithstanding the significant challenges faced by everyone, we have managed to achieve many important milestones in 2020.
“We commenced our deeper drill program in June this year and completed multiple deep holes – the deepest to 850 metres.
“We confirmed the presence of fertile intrusive rocks at depth, giving confidence that the extensive shallow high-grade mineralisation already discovered could also occur at depth."
Potential massive sulphide discovery
He said the company was further rewarded when downhole EM surveys in several deep holes lit up very powerful EM conductors.
“We have secured a diamond rig for January and look forward to starting 2021 with a new massive sulphide discovery.”
Resource definition drilling
The proposal for a starter mine operation at Mt Alexander envisages that mining will potentially commence at the Stricklands Prospect to be followed by mining at Investigators and Cathedrals.
Reverse circulation (RC) drilling of more than 10,000 metres to support a resource estimate of the shallow high-grade mineralisation at Investigators and Cathedrals prospects is scheduled to begin in February 2021.
Drilling at Investigators will target at least 20 untested EM conductors that represent outstanding targets for locating more massive nickel-copper sulphides.
The company is confident that the large number of conductors suggests that a significant volume of nickel-copper sulphide mineralisation is likely to be identified by the drilling.
Planned drilling and target areas with the new EM conductors (overlying MMR imagery).
Stricklands resource estimate
In 2020, resource definition drilling was completed at Stricklands to delineate a resource estimate for the shallow high-grade mineralisation discovered there.
The drill-out focused only on the shallow mineralisation, between 30 to 100 metres below surface, and did not include a drill-out of deeper extensions – consistent with the concept of a starter mine that can be executed quickly and for a very low capital cost.
A resource estimate for Stricklands will be finalised once the metallurgical test-work is completed.
High recoveries
High metallurgical recoveries have been achieved in test-work completed in Canada on nickel-copper sulphides from the Stricklands Prospect and this work shows the oxide and fresh composite is amenable to the production of separate nickel and copper concentrates from conventional flotation circuits.
Overall copper recoveries are 91% to 93%, overall nickel recoveries are 73% to 84% and talc up to 1% to 1.5%, which can be suppressed in the flotation process.
Further metallurgical test-work is planned to better optimise the potential mining and processing of ore from the project, with a scoping study for the Stricklands starter mine proposal to be completed once it has been received.
Scoping study progressing
A scoping study for the Stricklands starter mine is progressing well despite a number of delays caused by COVID-19 restrictions in Western Australia and in Canada.
The impact included limitations on completing work and prevented the company from meeting the initial target of delivering the scoping study in the current quarter.
Environmental studies have been completed with the final metallurgical test-work and the resource estimate required to complete the scoping study.
Although the company is disappointed by the delay, it may provide an opportunity to more quickly incorporate the Investigators and Cathedrals deposits into the scoping study and to increase the potential scale and value of the proposed mining operation.
Planned drilling and target areas along the Cathedrals Belt (overlying magnetic imagery RTP 1VD).
Looking forward
Prineas said: “We believe our high-grade nickel-copper sulphides are amongst the best mineralisation discovered in Western Australia with a combination of high-grades of nickel, copper, cobalt and platinum group metals that is unmatched by other discoveries.
“Thorough metallurgical test-work is required to develop a flowsheet that can maximise the value of all these metals in a potential mining and processing operation.
“Positive test-work results have been delivered by work in Perth and Canada.
“The test-work will be finalised next year, allowing for completion of a scoping study for a starter mine at Mt Alexander.
“The next year promises to be another exciting one as we continue to unlock the full value of our large, high-grade mineral system.”