This will be a BIG gold depositGold
Despite being highly conductive, gold does not occur in sufficient concentration to be detected directly with airborne geophysics. However, the effects of the geological processes which result in gold deposition are often detectable, and may have an effect over much larger areas than the gold deposit itself, presenting a larger target to the geophysical survey.
The geochemical alteration commonly associated with epithermal gold deposits may create clay minerals that increase conductivity, or deposit silica that decreases it. It may also reduce magnetite to sulphide, creating a magnetic low and conductivity high; or transport and deposit sulphides, also creating a magnetic high. The potassium enrichment (sericite alteration) associated with some gold deposition is sometimes the target of radiometric surveys. This variety of anomaly types may seem confusing, but with a basic knowledge of the deposit model being sought, the proper airborne geophysical system and interpretation can be employed.
Placer gold deposits can be difficult to detect, but it is sometimes possible to map the thickness of the coarse-grained (less conductive) beds among more clay rich sediments using EM surveys.
https://www.fugroairborne.com.au/service/mineral.php
https://pubs.usgs.gov/of/1995/ofr-95-0831/CHAP15.pdf