# How to fine tune a shaker table to catch 500# gold



## Finn from Ecuador (Oct 21, 2015)

Re: Further things which may be of interest to members
Table optimising

Many years ago I was involved with a project to maximise gold recovery from a milled ore by using a small (3') wilfley table to clean up concentrates and middlings from a bank of larger tables.

Due to environmental constraints chemical processing was not allowed on site.

A short period of operation revealed that running the table in its standard format was leading to losses of fine gold where the particle size was less than 50 micron screen size.

The gold particles were flattened from the milling and appreciable quantities were also lost from the plus 100 micron screen sizes.

Despite doing all of the standard optimisings of adjusting feed size screening, feed rate onto the table, table side tilt and water flow I could not get a major recovery improvement.

I went into the literature and found that the largest number and most useful papers were those from the British tin industry.

Basically they said that keeping a tight sizing on the feed was vital, I was already doing that so OK there.

Making sure that the table was level on the longitudinal axis was a fundamental which I was also doing.

Feed rate was best when a loose bed was set up along the table, don't put too little feed on the table nor try to put too much feed on the table.

Keeping the feed rate constant was also very important, I was feeding from a wet sump with a screw feeder so OK there also.

Side tilt was to be such that clay fraction particles were washed over the side of the table but the tilt was to be little enough that a middlings product could be readily separated at the end of the table.

Even when I had the table set up to cover all of the above parameters I was still losing fine gold.

The only area where I did not have full control was the side water coming onto the table, no matter how much I tried I could not get a perfectly even flow across the table.

I decided that I needed to improve the delivery of water to the table.

I did so by running a length of 3/4" copper pipe suspended about 4" above the side of the table where the water exited the original flow boxes.

The pipe was blanked off at the table exit end and was connected to a hose and ball valve at the feed supply end.

Ever 1" along the pipe was drilled a 1/8" hole.

When the water was turned on a curtain of water sprayed down onto the top edge of the table and delivered an even flow of water which could be easily adjusted for flow rate with the ball valve.

Even this change only partly improved the recovery, it was evident that there needed to be a difference in the water flow rate supplied to various parts of the table.

After a lot of testwork I settled on having the water delivery pipe as two pipes.

The holes remained the same size and spacing but the delivery was split into two parts.

The first part was as above but only extended 2/3 of the table.

The second part covered the last 1/3 of the table, each part was as a separate length of pipe so that adjustments could be made to either part without affecting the other part's flow rate.

In order to keep the water holes at the 1" spacing the pipe for the last 1/3 of the table was fed from the bottom of the table and the pipe ends almost touched.

Each pipe length had its own ball valve for separate flow adjustment.

The side wash water pipes were fed from an overflow overhead tank so that a constant head was maintained.

This was important on a mine site where valves were being opened and closed in other parts of the circuit, this would affect the pressure to the wash pipes.

This setup allowed recovery of free gold down to 25 microns, the disappointing part was the low weight of the 25 to 50 micron gold recovered, it looked a lot as a sheet like paint on the table but weighed far less.

On the plus side there was a substantial improvement in the plus 50 micron gold which did weigh well.

If run from a municipal water supply the overhead header tank may not be necessary depending on the vagaries of the particular supply.


Deano

This article was written by Deano in "Chemical Proses" section of this forum. I wanted to put it also here in mining section because i found it very educative.

Salud

Finn


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## denim (Oct 21, 2015)

Regarding the separation of fine gold out of a concentrate I will tell you about an article I read in a mining journal about a year ago. The author, I believe, was trying to devise a way to get super fine gold out of your typical black sand which is left over from panning some concentrates from a sluice box. He wanted to do something totally different from the 'Blue Bowl', spiral wheel, and the time consuming practice of razor blade on smooth surface to separate the fine gold from it's sand. He realized that gold is oleophilic, meaning it has an affinity for oil, and not water. Oil will stick to gold, where gold is hydrophobic and tends to shed water easily. Knowing this he set out to build an apparatus using some form of oil to trap gold not entirely unlike using mercury. He decided to use a piece of stainless sheet metal, bent with small sides along the length. Dimensions of this I don't recall. He then set this metal almost level- very slight incline downwards. He then covered it with a thin layer of vaseline petroleum jelly. Next he placed some of his sand across the top area of the metal ramp, just like you would with any sluice box. He then provided some very, very, very, slow water flow at the top of the ramp. This worked very similar to a sluice box. The fine particles of gold stuck to the jelly, and the sand (which is oleophobic and does not stick to oil well) flowed on down the ramp. If I remember correctly he said he checked the sand after all was complete to find very little to no gold using a loupe. The oil might present a problem to a refiner (probably could be dealt with using solvent, or inceneration), but at least he recovered his gold.


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## GOLDbuyerCA (Oct 22, 2015)

Subject lines like this, catch my attention, i am putting together a one square meter miller " like " table, that is powered by a Kilo watt variable audio oscillator, the output of the audio amplifier, is connected to the table , for the mechanical vibration energy. i found a like new amp, " nearly 6 thousand new " Techron Tec7572 amp, in California at auction, and i bid out to win, and hauled it back to Vancouver. So i am making my table, as tables here, even used, are over 25,000 for fine gold in creeks. i hope to get this done by summer of 2016,


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## Palladium (Oct 22, 2015)

I find your idea interesting goldbuyer. I had a theory for gravity separation of gold using cymatics, but not on a table. Please keep us updated!


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## DarkspARCS (Jan 4, 2023)

I recently was given this machine that has two strong vibratory motors (one for each foot and leg) that are adjusted through the use of the digital control board up top...
I've been trying to devise a way to create a vibratory sifter type table that would take your concentrates and vibrate the gold up top while causing the rest to vibrate down, just like tapping a gold pan.


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