St George Mining Ltd (ASX:SGQ) has intersected thick mafic-ultramafic units with nickel-copper sulphide mineralisation in drilling at the flagship Mt Alexander Project in WA's Goldfields region.
Two drill holes – MAD181 at Investigators and MAD183 at Fairbridge – delivered encouraging results with both intersecting mineralised mafic-ultramafic units at depth.
All high-grade nickel-copper sulphides discovered along the Cathedrals Belt to date are hosted in mafic-ultramafic intrusives.
The identification of further thick intrusives at depth increases confidence that additional nickel-copper sulphide mineralisation is present within the extensive Cathedrals Belt intrusive mineral system.
“Increases” potential for larger accumulations
Executive chairman John Prineas said: “The first two deep drill holes in the current campaign – MAD180 at Investigators and MAD182 at Cathedrals – successfully intersected intrusive-style rocks and confirmed the presence of prospective geology at depth.
“The next two holes – MAD181 at Investigators and MAD183 at Fairbridge – have provided another huge leap forward with thick intersections of mineralised mafic-ultramafic units.
“A very important aspect of this discovery is the preserved nature of the 48-metre thick unit intersected at Investigators.
“This significantly increases the potential likelihood for the presence of larger accumulations of nickel-copper mineralisation nearby.
“We are continuing our aggressive exploration programme, with downhole EM surveys underway and two diamond rigs drilling 24/7 to test more exciting nickel-copper sulphide targets.”
Thick mineralised mafic-ultramafic unit
MAD181 intersected 48.7 metres of thick mafic-ultramafic unit from 503 metres downhole, which includes a 10-metre-thick ultramafic with disseminated and blebby nickel-copper sulphides from 541 metres downhole.
The 48.7 metres of thick fertile mafic-ultramafic unit intersected by MAD181 is preserved and has not been structurally modified, supporting the potential for the presence of nickel-copper sulphide deposits that are intact and unaltered.
First deep drill hole at Fairbridge
MAD183 at Fairbridge intersected an 11.6-metre thick mafic-ultramafic unit with disseminated nickel-copper sulphides from 359.3 metres downhole.
The mineralised ultramafic intersected in MAD181 and MAD183 is on the same east-west horizon and located down-dip of the significant massive nickel-copper sulphide mineralisation already discovered at shallow depths along the Cathedrals Belt.
Diamond drilling continues
Two diamond drill rigs are continuously drilling at Mt Alexander.
MAD181 is at 770 metres downhole with drilling continuing while MAD183 was completed to 693.5 metres downhole.
The drill rig is now on hole MAD184 at Investigators to test a surface moving loop electromagnetic (MLEM) anomaly to the west of known high-grade nickel-copper sulphides.
New DHEM surveys underway
The DHEM survey crew arrived at site on August 26 and will survey MAD180, MAD181, MAD182 and MAD183 with data acquisition expected to take two days per drill hole.
Geophysical modelling and interpretation will follow, with further drill holes to be planned once results of the DHEM surveys are reviewed