I am a bit rusty on my geology, but my horseback opinion is that an airborne gravity survey is a useful but not very precise tool, and that the assay reports (good or bad) from the delineation core drilling or from mining a particularly encouraging 'hot spot' (or discouraging, unexpected barren zone) would be far more important.
Also, any new geologic interpretation or partially new interpretation of the detailed structure and habitat of the ore body can at times make all the difference. Or even better defining the various joint systems within the ore body can be important.
If anyone has been following McEwen Mining this past year, they will know what I mean about a 'new geologic interpretation'....(I believe it was at their Canadian Black Fox complex, but would have to check). Their old interpretation got them in trouble, but the new one seems to have fixed it.
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