b'FeatureImaging the supergene search space with ANTFigure 7. ANT velocity model with mineral resource estimate shells and drill hole traces. Horizontal slice is at 317 m depth. a. View of the AE-8 (NP) mineralised pod, and cross section through the model highlighting co-location of the relatively low seismic velocity in the vicinity of AE-8 (NP) and the abundant drill holes with highly weathered lithology (saprolite). b. Alternative view of the ANT model with cross section following fence of drill holes in the central part of the survey area that do not show enhanced saprolite development.in fractured and weathered bedrock. By depths of around 70 m80 m, the AEM signal is subdued, becoming more so towards the models maximum depth of around 156 m. The comparison suggests that conductive cover material, possibly residing in the weathering zone, may be masking any signal for the deeper portions of the AEM model. In the case of targeting supergeneFigure 8. Comparison of AEM and ANT results over the ANT survey area of the oxide zones, AEM is less useful since the oxide is less conductive,Alford East project. Note that the AEM results have been clipped to the bounds however, if deeper supergene zones of sulphide were present,of the ANT survey area and are part of a much larger survey, available via SARIG they may be able to be imaged. An interesting con\x1cuence ofhttps://catalog.sarig.sa.gov.au/geonetwork/srv/eng/catalog.search#/metadata/ae186f4c-30fa-476a-a159-74d2eb8bf5ccrelatively high EM response in the zone between the AE-8(NP). The colour stretch for and AE-8 copper shells that follows a similar trend to theboth the AEM and ANT results are cumulative distribution functions. Depth relatively low velocity features in the ANT model may add furthervalues are given relative to the surface. a. 3D view of the AEM survey results with the coppershells de\x1dned by Thor Energy PLC. b. AEM depth 22 m. c. ANT depth interest to these zones as areas for future exploration interest and32m. d. AEM depth 37 m. e. ANT depth 77 m. f. AEM depth 67 m. g. ANT depth highlights the complementarity of having geophysical methods122 m. h. AEM depth 127 m.that target di\x1ferent physical properties of the subsurface.Conclusions model has provided a complimentary view on the subsurface geology to the other available geophysical surveys. The velocity The purpose of the Alford East ANT survey was twofold, tomodel has imaged the thickness of the cover sediments, image basement-cover interface and any structure withinwith depths of the low velocity upper portion of the model the basement that may be controlling the location of deepercorrelating well with cover thicknesses from available drill hole troughs of weathering and potential supergene enrichment.data. In the Alford East example, the ANT survey provides a Both of these aims have been achieved, and the resulting 3Ddepth-constrained view of the subsurface geology, in an area 44 PREVIEWAPRIL 2024'