[defrost]

The Hackaday article is referring to Geoscience Australia geophysical surveys, Helicoptor VTEM specifically.

Fixed wing surveys are also a thing and more common over ground that is relatively flat, choppers get used for ground hugging steep ground - the cost per line kilometre goes up by a factor.

All the GA data (radiometrics, EM, magnetics, gravity, DTM's, etc) is available online or by request.

Eg: https://www.ga.gov.au/about/projects/resources/geophysical-a...

describes a dataset and links to raw data sets.