I always thought that aeromagnetic surveys give an indication of rock composition and structure at depth. From that, the data can be used to indicate the geometry of favourable host structures for mineralization.
If "mineralization" is taken to mean the presence of significant amounts of gold, then one would certainly check out the favourable structures, by trenching and drilling.
Is it possible that not all favourable host rock actually contains mineralization? I think so. And, if my thinking is correct, then it doesn't seem possible to define a resource from the air?
I own some shares.