b'Conferences and eventsNewsFigure 6.AEM results over Gonneville deposit. Left: HeliTEM Bz channel 15 (2.93.7ms). Right: Differential conductivity section at 6 512 400 N. Figure 7.ZTEM conductivity inversion results over Abra deposit (white outline).with a subsequent deeper vertical hole intersecting massiveground and downhole TDEM surveying resolved known copper-rich sulphides from 98 m (near the base of oxidation)mineralisation as weak EM conductor responses and to 235 m depth. Initial down-hole electromagnetic (DHTEM)petrophysical testing on core samples show this is caused surveying showed this DeGrussa conductor to be relativelyby galena. PDIP surveying resolved a +20 msec chargeability small; however, follow-up fixed loop (FLEM) and moving loopanomaly on the southern flank of the deposit, and this is (MLEM) surface electromagnetic surveys identified a significantlyrelated to disseminated galena, pyrite, chalcopyrite and larger nearby conductor called Conductor 1. Spectacularalteration. AMT-MT 2D inverted data sections resolved high-grade copper-gold intersections in Conductor 1 havethe Abra as a broad weakly conductive anomaly, which was made DeGrussa one of the most significant copper discoveriesalso resolved in 2D and 3D inversion modelling of airborne in Australia in recent years. Subsequent DHTEM surveying ledZTEM data. 2D seismic reflection surveying resolved Abra as to the discovery of two deep faulted extensions to the knownstrong flat-lying seismic reflectors which are bounded and mineralisation (Conductors 4 and 5). Core physical propertyoffset by faults and surrounded by a seismically bland zone. tests showed that EM was the best tool for detecting similarThe seismic reflections are related to significant density massive sulphide mineralisation in the area. Good contrasts incontrasts between high-density stratiform mineralisation chargeability, resistivity, and density confirmed that inducedin contact with low-density sedimentary host rocks, as polarisation and gravity surveying were also applicable methods.mineralisation and host rocks have similar seismic velocities. Surface MLEM, FLEM, SAM, gravity and magnetic surveys havePassive seismic HVSR surveying resolved the top of the been carried out. Of these, only the EM surveys have been usefuldeposit as a subtle layer sitting below a flat impedance for direct detection. Detailed airborne magnetic-radiometric andcontrast horizon interpreted as weathered siltstone on top of helicopter EM surveys have been flown. A weak but recognisablediagenetically cemented siltstone. The deposit remains open conductor was seen over the deposit in VTEM data. at depth, and a new Pb mineralised zone was discovered at depth just to the north from testing a late time VTEM The geophysical expression of the Abra sedimentaryanomaly.replacement Pb-Ag-Cu-Au deposit, WAThe geophysical signature of Nova-Bollinger; from Jayson Meyers*, David Stannard (Resource Potentials) and Angeloexploration to miningScopel (Galena Mining)Abra is a high-grade sedimentary hosted Pb deposit locatedBill Amann (Newexco Exploration)in the Paleoproterozoic Edmund Basin of Western Australia. ItNova Bollinger is the was discovered in 1981 and remained undeveloped untilfirst economic intrusive hosted NiS PGE deposit found within underground mining commenced in late 2021, 40 yearsthe Albany Fraser. I present and discuss the exploration following discovery. Mineralisation is blind with the topgeophysics up to the mining stage of the project. Initially, highly of the deposit occurring at 250 m depth and consists of aencouraging geological and geochemical results required follow stratiform apron of Pb-Ag-Ba mineralisation in a laminatedup which commenced with MLEM. Numerous anomalies were iron oxide and barite altered dolomite and siltstone overlyingdetected, of which one was selected for immediate testing. a feeder zone of chlorite altered, brecciated and veinedMaiden drilling returned massive NiS on target. Subsequent carbonaceous siltstone containing Pb-Ag mineralisation indrilling and DHTEM showed Nova-Bollinger to be a significant the core, transitioning to Pb-Cu and Cu-Au at depth. Abra isdiscovery. Given a good budget and corporate enthusiasm characterised by discrete geophysical anomaly responsesfurther geophysical work was carried out to characterise in magnetic, gravity, TDEM and IP survey data. A +450nTthe deposit(s) and to discover new lodes. This work includes magnetic anomaly is caused by magnetite within the lowergravity and IP and numerous forms of EM.part of the stratiform zone. Dense galena, barite, dolomite and iron oxide mineralisation in the apron, and galena inEverything I say is not necessarily true,the feeder zone, surrounded by lower density sedimentary host rocks, resulting in a +1 mGal gravity anomaly. Airborne,Bill Amann.23 PREVIEW FEBRUARY 2022'