St George Mining Ltd (ASX:SGQ) (FRA:S0G) is moving quickly to drill-test two very strong off-hole electromagnetic (EM) conductors identified in an unexplored area of the Mt Alexander Nickel-Copper Sulphide Project in WA.
The conductors have been modelled with conductivity of 49,000 and 16,200 Siemens respectively in a downhole EM survey and represent strong potential for a new discovery of massive sulphide mineralisation.
They were detected about 475 metres downhole in hole MAD184 and represent the deepest conductors ever identified at Mt Alexander with the company planning to test them with drilling starting next week.
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St George Mining’s executive chairman John Prineas said: “Our deep drill program is delivering excellent results with thick intrusive-style rocks and nickel-copper sulphide mineralisation intersected at depths not previously explored.
“The downhole EM surveys have delivered the breakthrough moment with two new exceptional conductors identified from MAD184 that are both interpreted to represent massive nickel-copper sulphides.
“The MAD184 conductors are particularly exciting as they are the deepest conductors ever identified in the Cathedrals Belt and located 800 metres to the west of previously intersected massive sulphides on the Cathedrals Belt.
“The potential discovery of massive sulphides at these new conductors could be our most important discovery to date.
“This would confirm the continuity of the high-grade mineralisation at depth and upgrade the western extension of the Cathedrals Belt, which covers the 2.5 kilometre-long West End Prospect that straddles the major Ida Fault, as a fertile and highly prospective area for further mineralisation.”
The current drill program at Mt Alexander is focused on deeper drilling to test conductive features identified by a number of geophysical surveys completed by St George across the Cathedrals Belt.
Identified drill targets are below and down-dip from the shallow high-grade deposits already discovered in the belt.
Plan view of the Cathedrals Belt showing areas of completed and planned drilling, overlaying interpreted geology and magnetics.
DHEM surveys on the completed drill holes are being used to identify discrete EM conductors for follow-up drilling.
MAD184 was drilled at the West End Prospect, in an area with no prior drilling and more than 800 metres northwest of known massive sulphides in the Cathedrals Belt.
The electrical signature of the new conductors is consistent with a massive sulphide source.
All other EM conductors with similar characteristics in the Cathedrals Belt have been confirmed by drilling to be massive sulphides with high grades of nickel, copper, cobalt and PGEs.
Modelling of the DHEM survey data for MAD184 defined two discrete EM plates for drill testing with the EM anomalism open in all directions and further drilling required to fully test the scale of the potential massive sulphide source.
Confident of next discovery
Prineas said: “The Cathedrals Belt is interpreted to dip to the northwest at about 40 degrees so, from a geological perspective, the MAD184 conductors are in an ideal location for the presence of massive sulphide mineralisation down-dip from the high-grade mineralisation already discovered near surface.
“With a 100% success rate in testing these kinds of conductors in the Cathedrals Belt, we are confident that our next significant discovery of massive nickel-copper sulphides is imminent.”
New EM conductors further confirm the camp-scale potential of the +16-kilometre-long Cathedrals Belt with four shallow high-grade nickel-copper sulphide deposits already discovered and new high-priority targets being established.
DHEM surveys in other recently completed drill holes have also identified additional EM anomalies which are being assessed and prioritised for drill testing.
Drilling to resume
Drilling at Mt Alexander has been paused while the DHEM surveys are completed.
Diamond drilling is scheduled to resume this weekend with one diamond rig due to arrive at site by Friday.
The first hole to be drilled will test the 49,000 Siemens conductor identified from the DHEM survey in MAD184, followed by a hole to test the 16,200 Siemens conductor from MAD184.
Further holes will be planned based on the results from DHEM surveys in the new holes as well as in MAD185 in which data indicated that a strong EM response was approaching at 325 metres.
Drilling and DHEM surveys have been confirmed as an effective way to explore at depth and will continue to be used across the Cathedrals Belt.