St George Mining Ltd (ASX:SGQ) has identified multiple EM conductors through ongoing exploration at its flagship Mt Alexander Project in the north-eastern Goldfields in Western Australia.
Through the use of downhole EM (DHEM) surveys in MAD185, MAD192 and MAD193 the company intersected mineralised ultramafic, with five EM conductors identified from MAD185 with the two highest priority targets modelled with conductivity of 33,100 siemens and 14,225 siemens respectively.
Two EM conductors were identified from MAD192 with modelled conductivity of 55,550 Siemens and 26,000 Siemens, respectively and four EM conductors were identified from MAD193 with the two highest priority targets modelled with conductivity of 4,585 Siemens and 2,850 Siemens, respectively.
All new EM conductors are within the large interpreted mafic-ultramafic unit that is known to host massive nickel-copper sulphides in other parts of the Cathedrals Belt at Mt Alexander Project.
“Breakthrough results”
Executive chairman Jon Prineas said: “The concurrent use of drilling and downhole EM surveys is continuing to deliver breakthrough results with outstanding nickel-copper sulphide targets identified in an area that has never been drilled.
“These are the deepest EM conductors identified in the Cathedrals Belt and support the continuity of high-grade mineralisation at depth and in the northwest down-dip direction of what we already know is a large intrusive mineral system.
“The identification of nickel-copper sulphides in the conductors modelled from MAD192 and MAD193 will establish the West End Prospect – which covers a 2.5-kilometre strike of the Cathedrals Belt and straddles the major Ida Fault – as a fertile and highly prospective area for further mineralisation.
“We are confident that the strongest of these new conductors will be confirmed by drilling to represent massive sulphide mineralisation.”
The new conductors are about 500 metres to 800 metres northwest of known massive sulphides in the Cathedrals Belt and represent excellent targets for the potential discovery of new nickel-copper sulphide deposits.
MAD185-DHEM results
MAD185 was completed to a downhole depth of 361.2 metres and intersected a 25.6-metre thick ultramafic unit from 300.47 metres, which included a 15-metre thick ultramafic with disseminated and blebby nickel-copper sulphides from 311.3 metres.
The first attempt to conduct a DHEM survey in this hole was unsuccessful because of a blockage at around 300 metres downhole.
That incomplete DHEM survey indicated that the DHEM probe was approaching an anomalous response at depth.
A DHEM survey of MAD185 was successfully completed last week with five anomalous responses recorded.
Two of the EM plates are modelled with very strong conductivity of 33,100 Siemens and 14,225 Siemens, respectively and these are interpreted to have a massive sulphide source.
The other three EM plates are modelled with conductivity of 1,000 Siemens (two plates) and 2,000 Siemens suggesting the source may be network textured sulphides or heavily disseminated sulphides.
Presence of multiple EM plates in this area is likely the result of structural complexity, given the presence of faulting in drill core.
This has the effect of dislocating the plates in what may have been a larger accumulation of sulphides.
Further drilling in this area, including below the plates and down-dip of the plates will further investigate this concept.
New drill holes
Drill holes are being designed to test the new EM conductors.
In addition, stratigraphic drilling will be planned to test the areas to the west and northwest of these conductors for further continuity of mineralisation.
Drilling was paused while the DHEM surveys were completed and will recommence once rig availability is confirmed.