I DK if the V3i differs too much from the GMT and MXT re. reading the ground and such, but I found it to be a nice theory that had little practical value when I was prospecting. First, it's easy enough to just eyeball a stream bed to see where the blacks & gold would lay down and, second, in a heavily mineralised area 'paystreaks' and such will be hard to find at anything other than shallow depths and will tend to be obscured because of other concentrations interfering. This is due to the ground being anything but uniform and often consisting of many large rocks/boulders at differing depths changing things up. If the ground was homogenous with the odd large rock creating an eddy, let's say, then I could see such a tool having 'some' utility, but I've yet to be in such a situation. Of course, I'm talking stream/river beds; there might very be other stuations where it would be useful. ..Willy. btw, the ground I hunt reads 84-86 on the MXT VDI , loaded with blacks and often with large bands/streaks on the surface.