b'2.5D AEM inversionFeatureOver the past five years, 2.5D inversion service work wasQuamby/Dugald River, Queensland, Australiacompleted by Intrepid on surveys using all major AEM systemsThe data used in this example came from the East Isa (TEM and FDEM), see Figure 1, and spread across mostVTEMTMPlus AEM survey. The survey was flown in 2016, and mineral exploration regions, see Figure 2. The bulk of thesewas funded under the Queensland Governments Future inversion projects was undertaken for conductive targetingResources (Mount Isa Geophysics) Initiative and managed and geological/ structural mapping purposes, with the splitby Geoscience Australia on behalf of the Geological Survey roughly equal. Approximately 10% of projects were related toof Queensland. The Initiative aims to attract explorers into groundwater mapping. greenfield terrains and to contribute to the discovery of the next generation of major mineral and energy deposits under shallow sedimentary cover.This example demonstrates the ability of 2.5D inversion technology to reliably image steeply-dipping and folded geology, and to present exploration targets ready for testing.Z component-only inversions were performed on eight lines of VTEMTMPlus that were 2 km apart over an 8 x 15 km block in the Quamby/Dugald River mineral district, east of Mt. Isa. A number of discrete exploration targets were defined, and some of these have a close spatial relationship to the shale hosted Pb/Zn mineralisation at Dugald River.Figure 3 shows the survey area and the location of the Dugald River mine relative to the VTEMTMPlus flight lines on a Google Figure 1.2.5D inversion service by AEM systemFigure 2.2.5D Inversion service by region.Examples of 2.5D inversion and forward modellingData from Quamby/Dugald River (Queensland, Australia) andFigure 3.Dugald River area showing the inverted VTEMTMPlus flight lines Kevitsa (Finland) are used to illustrate the advantages of 2.5Drelative to the mine site. Mapped synclinal features are highlighted by white inversions over the more commonly provided and utilised CDIssymbols and inclined drill holes are in magenta.and 1D inversions when the geology and targets sought do not fit the 1D assumption.Data from Elura (New South Wales, Australia) are used toEarth backdrop. The mapped synclinal features are highlighted illustrate the application of the Moksha software in tandemwith white symbols, and inclined drill holes are in magenta. with a full 3D geology modelling package to forward modelInversion results are presented for lines 15701 and 16101, which the performance of different AEM systems over a realisticare denoted in blue. Figure 4 shows the geology of the survey area exploration target. The detectability of deposit styles inwith the mapped synclinal features highlighted by red symbols.different weathering regimes using different systems can beThe 2.5D Z component-only inversion results in Figures 5 predetermined, resulting in a more cost-effective survey design. and 6 highlight the synclinally folded shale package (grey/AUGUST 2020 PREVIEW 34'