old BFO detectors

I've read in a couple of different places that this old tech is well suited to prospecting.
I would like to use it to find concentrations of black sand, which is usually associated with gold in highly
minerilized ground.
Tom or anyone with experience can you comment as to why this would be true of this tech.
I have tried to use my Whites GMT fo this purpose but not sure what the readings are actually telling me.
Also, is there a particular manufacturer that made a good prospecting BFO. I know Garrett made a few.

Thanks for any help

Tom

More people are looking for BFO's.....than selling...probably have the black sand idea to. Occasionally do see them on Ebay. I will take the time to keep an eye out for them if you request it. Any brand preference?

I have used quite a few old BFO's...........but never for prospecting. I don't feel 'qualified' to intelligently answer this question. My gut tells me to lean more towards a P.I.

I recall...........decades ago...........the old BFO's handled iron very well; yet, did not have much depth capabilities.

I did a little sniffing around regarding BFO's & black sand. I found this little snippet of info. You may wish to contact the mfg to validate info.

"Currently there is only one manufacturer that claims any black-sand finding ability, and that is Whites, with the MXT and GMT. THey give a reading on background mineralization, and using this reading you can find places that are "hotter" and thus have more black sands or other minerals within range of the search coil, which will only be a few inches to a foot or so of depth."

Thanks TerraDigger

I have the GMT, and the method I use is to pump the coil up and down and watch the number on the top left of the screen
which is % of black sand. Now were I pan there is b.s in every pan and the read outs never varied by more than 5-6% which
to me didn't indicate a large concentration . i also panned out some of these spots but didn't see much difference.
When it comes to BFO detectors, there were a ton of mfg who made them at one time. D-Tex I believe was one of the earlier one
that made a good detector. Garrett and Compass also made them. I haven't found a particular model yet that I would like, but some thing
designed for prospecting and not coins. If you have any suggestions that would be great.
I've also looked at the Falcon MD20 gold probe and am wondering if it is a BFO just by the way you tune it, very similar to some of the BFO's i've watched on youtube.

Tom
For nugget hunting I have been thinking of getting the TDI Pro, but don't think would would be useful for tracking black sand
I would have thought as a young boy the bfo detectors would have been the weapon of choice, or am i dating you a little to quickly?

Thanks for the help guys

Turtleman

Yes, true. A pulse induction unit is NOT good at tracking black sand..............as..............the P.I. unit works on the principle of time-domain decay-rate......................of which......................will inherently NOT see the black sand very much................because......when the 'receiver' is finally turned back on (after a deliberate delay).......the black sand response has decayed to the point of 'no detect'. BUT.............the advantage of a PI.......is the fact that this type of platform is much less affected by bad/mineralized dirt.

A BFO would give a rise in audio tone/volume (and meter deflection.....if so equipped) as the coil is swept perpendicularly over striations and stratified layers of black sand. You can also do this with today's VLF's (whilst in all-metal mode)......as long as the unit does not employ automatic ground tracking......and 'track out' the ground changes.

I used BFOs back in the 60s and early 70s. they do indicate the presence of black sand but not very deep. I think you will be better off using the GMT.

Do you know how to interpret the readings you get on the GMT? The owners manual doesn't go into gret depth for this application.

Thanks
Tom

There are 6 instructional videos produced by White's on YouTube for the GMT. They feature Jimmy 'Sierra' Normandie (a legend) and a brief appearence by Dave Johnson (a legend) when he was a engineer for White's. Here's the link to the page:

[www.youtube.com]



Look for titles "GMT instructional video" Parts 1-6


Hope it helps