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Using The GMT To Find Black Sand Paystreaks


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I have a sort of running disagreement with a very respected detectorist-prospector (not Steve) over the usefulness of these iron / black sand functions. I argue that while theoretically they could be used if conditions were just perfect, there are virtually no conditions in the real world that are perfect. In addition to what Jim mentioned, there are loads of other things like accumulations of hot rocks, change in the bedrock, etc. which would indicate as mineralization to a detector but have nothing to do with any useful accumulation of gold. Also, because of the fact that metal can be detected much deeper than mineralization, the black sand accumulation needs to be pretty close to the surface. Also, you have the effect of detecting many tiny objects - just as your detector responds better to a small half gram nugget than 10,000 pieces of gold dust that weigh 1/100th of a grain, your detector will see one golf ball sized chunk of magnetite far better than 10,000 pieces that weigh 1/100th of a gram spread out in a stream.  

I have never heard of anyone actually successfully using this function (and its on a number of detectors and mentioned in a number of books) to actually find gold. Kevin Hoagland tried unsuccessfully to find gold tracing black sand / mineralization on one of his Gold Trails videos. He found some mineralization but no gold to speak of. I think I could have done better just looking at the ground and picking sample spots on the basis of inside bends, rocks outcrops, boulders, etc.

In my opinion, its a design engineer's theoretical way to find gold accumulations which just is not practical for real life gold detecting.

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Thanks Chris, that would explain why I did so much head scratching, I found the mineralization but not the black sand, I guess it might work if a person was in an area where people had not been where the black sand levels were fairly uniform and then suddenly shot up in an area of about 5 or 6 feet square, but like you said if the signal is weak because the sand is deep then you are going to miss it completely, and such areas do not allow for big coils to be used due to the ground noise, So then it's back to square one again.

John.

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I find this all very interesting - including Chris' comments. I'm very new to detecting and so don't want to disagree but I wonder if there might be occasional real world conditions in which it could prove useful. Locally, we have diffuse fluvial flour gold everywhere, but reasonable concentrations are rare - neither the diffuse or concentrated varieties are detectable with current technology afaik excepting perhaps a Goldspear.

But I would be interested to read the river, detect for relative magnetite concentrations and then start test panning from there, should there be any value in that approach. 

Trying to track down that Hoagland video... any pointers?

Rex

 

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This one?....

Well after watching it ... It wasn't particularly enlightening.

 

 

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Thanks!  Interesting video but inconclusive - too bad there was no gold in the area he demonstrated the technique in.  On the other hand, Jeff seems to lend credence to the method... ?

Rex

 

 

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Again, its a debate.

The fact that Kevin found no gold with the mineralization method does not prove there is no gold there. I expect Kevin would not take them to a place to film his show unless he knew there was gold there.

I have never heard of anyone who has been truly successful with the method. I have heard of plenty of stories of competent prospectors who tried and were not successful. That does not prove it could never work, but there are plenty of reasons to believe that it would take just the perfect unusual set of rare circumstances to make it work. 

Jeff does not do a lot of detecting in and around streams, so I am not sure he has had actual success with it. Its almost like an old wives tale that everyone has heard and repeated but no one has ever seen it actually work under real field conditions. If Mythbusters was still running, perhaps I could refer it to them.  

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16 hours ago, johnedoe said:

Jim in Idaho...

I think they did years ago... It was a BFO machine....:smile:

LOL...yes, John, they did. And I've still got my old Garrett Master Hunter BFO, with two double coil sets for it.

Jim

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Chris, the only real use I can see for this feature is trying to locate pay streaks of flour gold. That's what I really wanted it for. I live very close to the Snake River, and the river is full of very tiny flour gold.....the amount is estimated in the billions of dollars worth. Because of its shape factor, that flour rides well up in the water column, and is deposited on the surface as the high water goes down. The follow the black sand feature could be useful, if it worked, to find those surface paystreaks. As far as finding deeper larger gold with that feature, I agree with you...not much benefit.

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Here is another video using the GMT to track black sands..... again , not a lot of info but at least it shows a little.

All ya need to watch is about the first two and a half minutes ....

 

 

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