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GMX Overloading On Black Sand


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 When I use my Gmx with the 6' concentric  coil in a beach section with a high  concentration of black sand it is overloading all the time and I have to raise coil about an inch   to have it go away.I then go  for the nice zip sound and I usually get a coin because all the light stuff has been swept away. This 48kz  machine is very  hot with this coil.Would a bigger  DD coil stop this overloading?

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If coil sizes are identical than a DD will generally handle bad ground better than a concentric.

Also, since small coils “see” less ground than a large coil, small coils will often handle bad ground better than larger coils.

So you gain by going DD but lose by going larger. Going DD will help, but going to a larger DD may be no better and a much larger DD may be worse.

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I don't have a GMX detector ,,,, but I will write my experience with Mxt and 5.3 "concentric coil and DD coils of different sizes ....

At 7 bar Fe3o4 .. Black Sand ... Whites MXT with ... 5.3 "concentric coil will go to Overload if you set Gain more than 6-6.5 ...

on 7 "DD Ultimate and 7" DD Mars Lion coils, as well as 10 "DD, 6X8  DD SEF and 12x 10" DD SEF coils, you can safely set these DD coils at the Gain level to 9.5 .... without Overload and coil I will still work normally .... and detect just above Black sand ..

If you set the Gain to 10 or more, these DD coils will also go overload ....

It follows that a DD coil of this size should help you in the detection of GMX ...

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,,,,,,

Another advice is .. because I know that the GMX has a Shift Frequency function, so I would advise to make a frequency shift from the center frequency of the detector upwards .... this should weaken the signal on the receiving part of the RX coil and the detector should be more resistant to mineralization terrain ...

Here, after deviating the frequency, you must verify how much you also have a smaller detection range of the detector.
because a stronger deviation from the center frequency is also reflected in the loss of detection range.

  Use the Shift Frequency - which I use classically frequency shift - it helped me on several Vlf detectors .....

For Detectors with Direct sampling *TX, I no longer guarantee that this method will also help ...
 

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I don't know what area you are in but if I were you I would be running that black sand through a beach sluice or a gold cube.....

Take a look at my thread on beach mining.

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What kind of recovery equipment were you using.

There is a real technique to recovering fine beach gold. and many factors come into play in the process.

Water flow, sluice angle, feed rate, material size, and mats ..... all have to work together.

The gold cube is great since it is already setup for the proper angle. This then leaves you with 3 factors that have to balance and that is water flow rate and feed rate, and classification of material if it is a mix of pebbles and cobble and sand. If it is all sand your golden and no classification is required... As to mats the cube comes with good mats out of the box..... You do have to make sure ALL air pockets in the mats are cleared since the fine gold will just float across the top of those little bubble pockets.

Water flow rate is also very easy since those rates are already part of the GC system which is an 1100 GPH pump. However using unto 1500 GPH also works quite well.....

This now only leaves you with 2 more variables Material size...Which should be less than 1/8th inch and feed rate. You have to allow the mats to work.... You can't just drop a shovel full of sand on them and expect good results.

 

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