Detecting Nuggets in sluicing tailings stream

[Chrisdw]

I was watching gold rush recently and they talked about screening off anything bigger than 7mm from the sluicing system.
The rest goes out the tailings shoot.
They would sacrifice the nuggets for the flake.
Also they would miss any gold bearing quartz.

Seems to me that there should be a way to detect and divert tailings that could be gold bearing for later processing searching.
So I have been thinking of how best to do that and thought others would have ideas too, please chime in.

Could a detecting system be built into the tailings conveyor system?
There would need to be work on isolating metal from an area of the conveyor.
Could a Delrin support section with coils pointing up through the belt work?
I checked on the belts and many rock belts are made without metal plys and the joining cleat too.
Speed of the belt and timing to a diverter system would have to be considered.
Alternatively could the tailings be detected and diverted as they are shot through the air or a non metallic pipe?

What detecting technology would work best here?

Thanks for entertaining my idle thoughts
Chris

[Ferric Toes]

I was watching gold rush recently and they talked about screening off anything bigger than 7mm from the sluicing system.
The rest goes out the tailings shoot.
They would sacrifice the nuggets for the flake.
Also they would miss any gold bearing quartz.

Seems to me that there should be a way to detect and divert tailings that could be gold bearing for later processing searching.
So I have been thinking of how best to do that and thought others would have ideas too, please chime in.

Could a detecting system be built into the tailings conveyor system?
There would need to be work on isolating metal from an area of the conveyor.
Could a Delrin support section with coils pointing up through the belt work?
I checked on the belts and many rock belts are made without metal plys and the joining cleat too.
Speed of the belt and timing to a diverter system would have to be considered.
Alternatively could the tailings be detected and diverted as they are shot through the air or a non metallic pipe?

What detecting technology would work best here?

Thanks for entertaining my idle thoughts
Chris

Hi Chris,
I would be surprised if such a system is not already in use for the application you described. This type of detector has been used for many years on factory conveyor systems and using the Pulse Induction method, which in these type of applications can be run at higher sensitivities than are commonly available in the hobby gold prospecting market. If the gold is in iron mineralised ground, such as in Australia, then ground compensation would be needed, but that would not be a problem to incorporate.

Even belts with metal cleats can be catered for by having a small sensor to detect the cleat and disable the detector receiver for the short time that the cleat passes over the search coil. The cleat sensor has a settable delay so that the distance between the cleat sensor and main coil is compensated, which obviously depends on belt speed. Preferred are stainless steel cleats as these give less signal.

There are different types of diverter, which are actuated when the object (gold) passes over the search coil. One is a flap valve under a vertical 'drop through' pipe at the end of the conveyor, which diverts the rock fragments containing gold into a separate bin. Another is a lateral pusher which will push a coil's width of rock off the conveyor when the signal reaches a preset threshold, or an angled type, much like a railroad switch. The speed of the actuating mechanism is important and can be electronic solenoid driven, or an air blast valve.

This is a big subject with lots of variables, but yes it can be done.

Eric.

[homefire]

Trust me. Someone is keeping tabs on the tailing with a detector. LOL

[Tim]

Not much gold over here in SA, but it would be interesting to run a detector around under a quartz crushing plant-plenty of them around. But getting permission in this litigious and politically correct world would be another thing entirely.

Yes Eric, many food manufacturing lines also have detectors and mechanisms that could be salvaged and adapted also.

[Chrisdw]

Eric
Yes I figured this has been tried before but on the Gold Rush show the tailings just pile up without but a thought about what might have gotten through.
The tailings are all washed so any mineralized ground still on the tailings is minimal.

Tim - That is a good point about food processing as a model but need to then focus on gold and handling rocks.

I would think there would be a market for the quartz with gold flakes in it from a mineral collector point of view.

Chris

[homefire]

Here in NM all the old tailing piles get hit. Back in the time some of the mines were being worked with gold being $16.00 $30.00 a Oz!! Stuff you and I would drool over would be pushed aside simply not worth the efforts.