Fine Gold Question

[kilnmaint]

I have a Proline 3" combo rig. The area I have close to me has very fine (-30) gold. Using the rig as a highbanker, I have added classification on top of the grizzley. the largest rock getting through is 1/4" or so. I can run the engine at 1/2 throttles or less. This seems to work well, I catch fine gold, but the digging is tough!! When i dredge, the sluice loads up with rocks unless I open the engine up ,. Then the material all blows out the back. Proline has said to dredge with the sluice as flat as possibile and do not use a diverter under the grizzley.. Unless I have a tender continually moving out the rocks, they will pile up!! Any suggestions? I have miner's moss with burlap under it. I get very little gold from the crash box area when I dredge or highbank. I am working right at the waterline and into the bank. Last Friday two of us with shovels got two clean ups in a day. Normally I will get 3 to 4 when dredging. Basically half of the production . Any body solved this problem?

 

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[Hoser John]

Dump the moss/burlap and go with carpet. A highbanker is a highbanker and thats the design flaw. It does nothing but loadup and impact solid as cement when ever the flow is interupted. Just paint a few small lead weights and run'm on through. To thine own self be true and the truth is self evident. Simply add your additional classification to the top in a Z fashion like we did on the good ol'PESCO line and troubles eliminated completely---John

 

[Goodyguy]

You could try a drop riffle sluice, they are great on the fine stuff and easier to clean than carpet. The larger gravels and light sand just goes right off the sluice and only the heavies end up in the drop channels.

Cheaper to just go with only carpet under your riffle tray.
GG~

 

[Klondikeike]

Klondike here....

No matter what you are running.... high banker or dredge....or commercial operation... the rule of thumb I have ALWAYS worked with ..since learning how to actually mine gold... beyond a recreational situation... is as follows....

There are several adjustments that need to be correct in order for ANY sluice box to be functioning at maximum capacity with maximum recovery...assuming a standard Hungarian riffle...

1) The sluice box angle... generally 1 1/2 to 2 inch to the foot drop... But for some materials, water flow and size of material may have
you adjusting outside of those general guidelines...

2) Amount of water flow.... all based on types of material and material size....

What I look for is this.... this is very important... watch your larger or largest rocks....they should be "WALKING" down the sluice box.... If your larger rocks move and slightly hesitate at each riffle..then "walk" over that riffle slowly to the next one.. and "walk" over that one slowly..almost stopping for just a slightest moment... ALL your settings are correct....

IF NOT.. you may need to adjust the angle... or the amount of water and so forth...until you achieve the ..."WALK"... it doesn't matter if you're running 5 inch minus or 1 inch minus.. the principal remains the same....

One problem with off the shelf equipment.. it is meant to be like ...ONE SIZE FITS ALL... but that is so far from the truth when it comes to real gold recovery...Back in the day, before Keene and others were building mass produced mining equipment....... we had to build our dredges...and sluices... we always built them with the proper adjustments in them to make them work properly... However, for the average recreational prospector the mas produced equipment works fine...... but as you get more experience and want a larger operation... you'll start to apply some of these principals...

Since gold is so much heavier that most everything you'll be mining...when the large rocks properly WALK down your box.. the small fine placer gold will not and your recovery will go up... and when in a commercial setting...the use of jigs and or centrifuges help recover the very smallest fine gold particles...yet the boxes will remain free of clogs and the riffles will not pack up and will work correctly, capturing the gold and black sands....

Hope this helps someone....

Klondike...

 

[Goodyguy]

Klondike,
As usual you provide detailed answers that get to the heart of the issue.

 

[kilnmaint]

Thanks Guys,

You all bring a lot of experience to the table. I pretty well have the set up right for highbanking. The additional classification and slower water flow does have the rocks "walking" down the sluice. It is when i dredge that I am not comfortable with the setup. I have a "combo" with a crash box not a flair. The water "boils" in the box . Proline recommends the boil to be up to the grizzley with a flat sluice. When i set up this way , the larger rocks pile up in the botton 1/3 of the sluice. The sluice angle is limited due to the height of the pontoons, so water flow(engine speed) is the basic adjustment. I am going tomorrow to a new place( 1850's placer mine that has been "off limits" for years). I plan to try your suggestions and see what happens. I will post later this week. Thanks

 

[Goodyguy]

Pretty much having a "tender" to keep the sluice clear is just the nature of the beast on 3" and larger dredges due to lack of classification of the larger gravels and rocks as far as I know

GG~

 

[Klondikeike]

Hey kilnmaint.....

Without being there and seeing what your situation is... I will offer you this advice....and it will go against your normal logic... but just try it...and see if it works... from my experience..it will...

Most of us have a natural and often realized fear of running too steep of a box.... thinking we will blow out the gold.. and in some cases it will... if no attention is paid to the other adjustments mentioned before..

But try some how lifting the upper box and header so you are running a steeper box when dredging....until you get the WALK... and I think you'll find the box will work better... and a higher recovery rate ....

If the riffles are working correctly.. the "suction" of the internal EDDIE currents will keep the riffles clean and the small worthless rubble "hopping" around deep inside the riffles....the gold will stay there... even the small fine grained placers...


Or you can keep it the same and make use of a dredge tender...throwing rocks...

There can also be an additional cause to the box loading up with large rocks... which is hard to learn NOT to do when dredging.. that is ...SLOW down ....your feed... allow the box to process the larger rocks... when stuffing lots and lots of material all at once to the header.. where are all those rocks going to do go...? no where.....! they will just load up and lock into each other.... I am just a guilty as the next... we l want to process as much material as possible... so we often feed the box too fast.... too much...

This is one reason that the hydraulic mines of yesteryear were so infective....and lost more gold than they found...they couldn't control the material flow into the and through the box...

Hope this helps....


Klondike...

 

[richter]

Do you still have this box and this problem?

I did some modifications to mine and it keeps the fine gold perfectly. I can post them if you need.

 

[Vance in AK]

Dump the moss/burlap and go with carpet. A highbanker is a highbanker and thats the design flaw. It does nothing but loadup and impact solid as cement when ever the flow is interupted. Just paint a few small lead weights and run'm on through. To thine own self be true and the truth is self evident. Simply add your additional classification to the top in a Z fashion like we did on the good ol'PESCO line and troubles eliminated completely---John

John, pictures? I don't remember what PESCO highbankers looked like!