Acrylic Riffle tray?
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Thread: Acrylic Riffle tray?

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  1. #1
    us
    Gbonus Uralias

    Dec 2014
    Ventura Ca
    Gold Bug Pro w/ NEL coil. Minelab Xterra 705, Bazooka Snipers (24" and 30"). Royal Folding Sluice with Gold hog mats. Thompson 12V Puffer Drywasher.
    495
    942 times
    All Types Of Treasure Hunting

    Acrylic Riffle tray?

    Static electric charge and drywashing are good....

    So I got to thinking about making a riffle tray where the frame and riffles are made entirely of Acrylic.
    Acrylic loves making static and I feel an Acrylic frame should be strong enough to handle the work.

    Or better yet, retain the aluminum frame of riffle tray and the riffle bars alone are clear acrylic.

    Just Thinking out loud here I guess.

    Opinions?......has it been done already and I'm way late?

  2. #2
    us
    Aug 2014
    SoCal
    SDC2300, Whippet, 151, GH, shovel, brain
    251
    398 times
    Prospecting
    I believe Keene's new 141-S has something similar going on. Apparently it creates a much stronger charge that the previous version. I want one. Bad.

  3. #3
    Charter Member
    us
    Nov 2010
    The Great Southwest
    3,806
    11157 times
    Prospecting
    Quote Originally Posted by G-bone View Post
    Static electric charge and drywashing are good....
    That's not really the case except in laboratory conditions. It's one of those technical things that just don't work out in real life mining.

    Here's the true story about how this rumor of static electricity helping trap gold in a drywasher got started.

    Back at the turn of the century (1900's) a really smart guy solved a minor problem in separating the blond sands from the non magnetic iron deposits around Lake Superior. The triboelectric effect was used to separate the materials with an electric charge plate.

    That bit of success led this really smart guy to think the process would work on small particles of gold so he set up an experiment with dry blond sands and gold particles using similar methods as the iron ore separation machine. With a few modifications and a little different setup he managed to pull the gold out of his sand mix with an electric charge!

    Now this really smart guy knew a place with about 15 billion dollars of fine gold just waiting for an efficient dry processing method to get all that free gold separated. So he bought 54,000 acres of this deposit and set about making a huge electrostatic drywasher. All in all he spent about $7,500,000 OPM in today's money (7.5 million dollars of Other Peoples Money) setting up this huge operation. He and all those investors just knew they were all going to be rich, after all this guy was really smart and really successful!

    They ran into a few problems with their huge new plant right off the bat. It seems the gold and other mineral particles had to be very close in size for the process to have any effect so they set up a huge classifying operation. Problem solved right? Not quite.

    After they got enough material classified to start up this huge dry processor again they discovered another problem, the magnetic minerals interrupted the triboelectric effect at a very small scale but enough so the gold was no longer being retained. So off to the drawing board to figure out how to get all those magnetic materials separated. Being the smart guy he was this wasn't a huge problem but as with all the previous solutions the gold recovery was being diminished with each additional solution. By now the expense of preparing the placer material and the reduced recovery rates were making the operation pretty marginal but still possibly profitable in the long run.

    So with a big pile of demagnetized and finely classified material stocked up they started up the huge electrostatic drywasher again. To their surprise they were getting hardly any gold recovery! This smart guy tested and experimented for a while and finally came up with the answer as to why the triboelectric effect wasn't collecting gold as expected. The simple answer was in cooler evenings the dry, classified, demagnetized prepared placer sands absorbed a little bit of moisture from the dry air. The upshot was even as little as 2% moisture caused the triboelectric effect to break down! Experiments in drying the material produced the same problems miners face to this day when attempting to dry commercial quantities of wet minerals. Any volume at all rapidly becomes too expensive to be profitable.

    If that wasn't enough this really smart guy hadn't figured on what would happen to his ore and equipment when the first of the monsoon rains came in mid summer. Suffice it to say electric charged plates and electric motors don't get along with water. Soon smoke was leaking out everywhere and as any modern miner knows electric stuff runs on smoke - let the smoke out and the electric part becomes no better than a paperweight for mining purposes. Add in some wicked winter storms a couple of months later and the local miners stopped showing up for work and even began to question how smart this famous smart guy really was. Long story short the Smart guy moves back east, Other Peoples Money is lost, the giant electrostatic drywasher is sold off for scrap.

    The only thing left today of this failed mining operation is the piles of classified and cleaned placer material. This place with all the gold still produces well with wet processing methods but drywashing to this day, "static electricity" or not, is not profitable.

    How do I know all this? The land this really smart guy bought was the Ortiz Mining Grant in New Mexico where our crew has been mining for several years. The pile from the failed giant electrostatic drywasher sits just next to our mining lands within sight of our own wet processing operation.

    Oh and the really smart guy? Thomas Edison!

    So if you find a deposit rich enough to overcome the problems of classification, magnetics, moisture and weather and still make a profit with electrostatic recovery I'm betting it would still be even more profitable to just truck in the water needed to wet process unclassified, magnetic material of any moisture content.

    Theory is a real bugger when mining reality strikes. The only profit you are going to get out of an electrostatic drywasher is more dry grit sticking to more moving parts and giving your drywasher a much shorter life. That makes more sales and more profit for sellers of drywashers but more expense and breakdowns for the miner trying to get the most out of his equipment.

    Luckily this is easy to fix. Just run a metal strip to ground from your charged drywasher riffles. Your equipment will thank you.

    Here's the consensus on electrostatic gold recovery today from Minerals Engineering Volume 58, April 2014:

    The charge is influenced by the intensity of the triboelectric contact, the humidity, and the chemical surface modifications of the two materials in contact. A sufficient charge results in an electrostatic attachment that can be utilized for selective dry gold separation. The sensitivity of the process renders the application of this technique difficult. In modern gold beneficiation, electrostatic separation via triboelectricity has been tested but has no practical use.
    By the way - the triboelectric effect depends on a non conductor so any possible triboelectric benefit requires something like wool or silk. Using aluminum or Acrylic alone to create the charge won't result in any triboelectric effect.

    Heavy Pans

  4. #4
    us
    Mar 2012
    1,419
    1641 times
    All Types Of Treasure Hunting
    Edison was kinda obsessed with anything electric,as long as it wasn't AC. I guess that was one of the thousand ways it didn't work.
    G-bone likes this.

  5. #5
    us
    Gbonus Uralias

    Dec 2014
    Ventura Ca
    Gold Bug Pro w/ NEL coil. Minelab Xterra 705, Bazooka Snipers (24" and 30"). Royal Folding Sluice with Gold hog mats. Thompson 12V Puffer Drywasher.
    495
    942 times
    All Types Of Treasure Hunting
    Most excellent story .
    Thanks Clay!!
    Clay Diggins and Clay Diggins like this.

  6. #6
    us
    Aug 2014
    SoCal
    SDC2300, Whippet, 151, GH, shovel, brain
    251
    398 times
    Prospecting
    Interesting!

 

 

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