I am no Geo-physical Engineer, so I don't know what to make of...

I am no Geo-physical Engineer, so I don't know what to make of the pictures that are put up on some of the announcements by mining companies.

The image below is from the ann. of 21/6/18 by MEI - Outstanding Geophysical Results at Mulligan

The image was generated by a "closely spaced, ground based geophysics program of induced polarization (IP) resistivity and magnetics"

Then we had the 3D Modelling of the 2012 Aero TEM survey at Joyce


And today we have a different type of survey again "an airborne VTEM survey", which generated the following

I understand MEI are on a budget, but I do wonder why they have used 3 different types of survey formats to generate drilling targets. In fact I am very curious about why this is so, curious to the point that I most likely have to talk with Andrew Tunks about the subject.

Does anyone here know why MEI would have taken this approach ? Or does anyone here know about geophysical techniques employed to develop drilling targets, because as I see it MEI have used 3 different approaches to develop drilling targets over the 2nd half of this year.