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Fine Gold Dredge

Posted by Joshua Andrews on October 2, 2010 at 9:38pm in General Discussions
I have a location with lots of fine gold much 100 mesh.
Been taking buckets home classified to 1/4 inch and sieved down more.
Filled up a 100 gallon drum so far and can pan dozens of tiny colors per cup.
Plan to classify further and run on miller table.

Now if using a 4inch dredge with three stage sluice will i lose much of the 100 mesh gold or make it up with the speed of material run?


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Replies

  • mark johnson December 7, 2010 at 11:09pm
    don,t let box get to full. use miners moss, slow down feed,flaten out angle of box. that should help.
  • Joshua Andrews December 5, 2010 at 11:29pm
    Thanks for your replies guys.
    Now when I was out there with the dredge to help keep the rocks out the sluice had miners moss over top of the last third. Only used the dredge at that place for one day. Plugged the suction a few times, but you learn..

    Later got some nice gold with the hibanker, having 1/4 in screen in the grizzly, and will find some more close to 1/8 to 1/16 in to put over it.
    How about using a mud flap to keep things pushed down in the sluice.
  • Dean Stone December 5, 2010 at 11:06pm
    Hi Joshua, Run your dredge at a slower pace, and set your sluice almost flat or on a sligh up hill run. Watch that your sluice don,t fill with larger rocks.pull bottom sluic ut all the way till it stops. Good Luck Dean
    • Astro Bouncer > Dean Stone December 5, 2010 at 11:19pm
      Hey Joshua, also, for fine gold recovery, classification is the key. You should screen out any gravel larger then the biggest size gold you might find. A 1/4 inch piece of gravel (4 mesh) will displace a good bit of fines. But screened down to 12 mesh or even 20, you will catch and hold smaller gold much easier. Also, for a drop riffle sluice/dredge you can get by with much less flow/velocity of water then a conventional Hungarian riffle setup.
  • Larry Broman December 5, 2010 at 8:58am
    You might take a look at the popandson sluice which was developed to stop the use of mercury to recover fine gold by the small scale miners of mongolia. this has been able to recover 350 mesh gold ( Talcum powder fine)
    i use many of its features in the sluices i use and yup it works

    http://img515.imageshack.us/img515/5421/psasmsluicemi5.jpg

    articles about this concept can be read over at the Alaska gold forum
    • KEN AKA BIG FOOT MOUNTAIN MAN ID > Larry Broman December 5, 2010 at 9:09am
      the vortex matting will do the samething in a dredge or banker or sluice without all the hassel of the clean up with powered fine gold which is very hard to see its always gonna be hard to recover from the black sand
  • Don Gill November 5, 2010 at 1:03am
    A four inch is a beast:)

    I work in areas with very simular size gold (100+ mesh) here in Washington State. I use a drop riffle design by gold dredge builders warehouse and love it. I agree with Bill - you need to check our tailings to verify that you are not hogging too fast, or have too much flow and are blowing out the gold. It can be a challenge to get the right balance.

    You might also consider examining where in your box your gold is building up and adjust your speed accordingly. If you are seeing your gold in the middle or the tail end of your sluice, slow it down. When operating properly, the vast majority of your gold should be at the top of your sluice. It's easy to see in a constant upgrading drop riffle dredge.

    Best of luck,
    Don Gill
    http://prospectorsplus.com
    • Joshua Andrews > Don Gill November 5, 2010 at 2:50am
      Thanks.
      Whats drop riffle?
      • Joshua Andrews > Joshua Andrews November 5, 2010 at 2:57am
        UTFSS

        http://forum.treasurenet.com/index.php?topic=323849.0

        Answered that one. And my thoughts exactly. Same thing as the angus mackirk.
        And some prices on for those dredges there competitive.
        • Don Gill > Joshua Andrews November 5, 2010 at 10:23am
          Yeah beat me to the punch. The link to the home built version pretty much tells the story - little need to classify, lower water volume needed, very fine gold capturing ability.

          The reason why the author found little black sand was because drop riffle design is a constant upgrader, in that the gold (or other heavy materials like platinum or osmodium, etc) will upgrade anything lighter - including the black sands without loosing the good stuff. What you are left with is the heaviest of the heaviest.

          Angus MacKirk (I own and use) and Le Trap (I have never used but know people who love them) is the bomb - are both good examples of drop riffle design at a very decent price points.

          Don Gill
          ProspectorsPlus.com
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