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Eric N

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Everything posted by Eric N

  1. Eric N

    Cleaning Quartz/gold

    I stand corrected. I gave the contents of the dry variety. The liquid version has Hydroflouric acid as one component of the trade secret mixture. As gold is an alloy, it is probable that the HF and other unknown chemicals are reacting with the alloy. Looking in the CRC Handbook it reveals that silver reacts with HF and AgF is yellow, AgF2 is brown and Ag2F is yellow as well. Mineral specimens are a hodge-podge of chemicals, so there could be other chemicals reacting as well. And the other components of Whink are trade secrets. Who knows what is reacting with what? Just a guess that the gold might have some copper in it reacting with something else in the Whink. Copper and HF tends to be white and black compounds. Iron could be involved and HF could turn it into iron flouride octahydrate which is green-black. So the color might be a similar outcome as mixing a bunch of different color paints. Keep in mind that HF is really bad for organics like the human body. I always recommend reading the MSDS before using chemicals. Having a CRC Handbook of Chemistry and Physics around is a good idea. Used books are far cheaper than new and unless you are trying to be on the cutting edge of chemistry, older editions are just fine. eric
  2. Eric N

    Cleaning Quartz/gold

    I think you misspelled the product. Wink is an acrylic polymer. Whink is a rust and stain remover. Ingredients are: Sodium bisulfate Sodium hydrosulfite Sodium chloride Sodium Carbonate Citric acid Blue crystals Source Whink MSDS Added to water generates sulfur dioxide. eric
  3. Eric N

    Small Scale Hard Rock Mining

    Your previous post stated that you were working a tailings pile. From that we can assume minimal cost to extract the ore from the gangue. So now you have to figure the cost of milling as it wold be the highest cost input. You got 0.4 grams per 40 lbs of hand-sorted ore That equates to 20 grams per ton. Pretty good in my uninformed opinion. The next question is amount of ore in the tailings pile. From this you could determine the sizing of the milling equipment to meet the requirements of cost-efficiency. Whatever provides the through-put you desire must pay its way (operational costs and amortization) and still provide a reasonable net profit. As my background is in shovel-in placer operations, I have no idea what the daily through-put of your current milling equipment. But like I stated, I'm pretty unqualified to offer any further ideas. I only understand net v. gross profit when it comes to hard-rock. eric
  4. Just got done downloading. Fairly large (2 sheets and about 40MB total) and don't forget the 204 page pamphlet that goes with it. eric
  5. Eric N

    Red Waxy Clay

    Water is the primary mechanism that reduces the oxides to clays. Keep in mind that this water carries dissolved oxygen, a small bit of carbon dioxide and isn't pH neutral. The same water can alter any sulfides and remobilize downward them out of the oxidation zone. A favorite reference of mine and probably out of print is: "Ore Deposits" Park and MacDiarmid, 1964, W.H. Freeman and Company. If the evidence suggests that the quartz matrix could carry gold, then I would crush, wash and pan the material. eric
  6. Eric N

    Red Waxy Clay

    The feldspars and micas degrade into clay. eric
  7. Assays are done by weight. Use google and type in "fire assay". Quit trying to over think this. This isn't an assay to determine if it is .995 fine or .9999 fine. It is just a basic assay. The deposit isn't homogeneous, continuous or exactly defined in size and shape. The question is, "Is this deposit economic?" This is chemistry at the level not much higher than, "Hey dude, look what happens if we mix vinegar and baking soda." All of your over-thinking is based upon quantitative chemistry requiring technical or higher grade chemical reagents. Gold in it's natural state does NOT, I say again does NOT, have a density of 19.3grams/cubic centimeter. The gangue rock may or may not have an S.G of 2.8, but most metal sulfides have S.G. >5.0. You are dealing with a bushel basket of unknowns. Most are irrelevant. "Seems PPM notation needs to be scrapped !!!" No sir. You need to put away your junior Nobel prize in chemistry set and learn something about mining. PPM is exactly what works best. 1PPM is 1 gram per tonne. A tonne is 1000 kilograms A cubic meter of ore carrying rock will weigh about 2.5-2.7 tonnes. Ergo that 1PPM translates to 2.5-2.7 grams per cubic meter. There are 31.1 grams per ounce troy (ozt). Gold is sold by weight. Most gold prices are quoted in USD/ozt. Excavation of rock is measured by volume. You drive an adit in feet or meters. Moving the ore bearing rock to the mill is by weight and volume. Milling is rated in tons/tonnes per hour. PPM makes abundant sense. Quoting some drivel from wiki just infers that you place a good deal of confidence in unfounded opinions formed from people living in their parent's basement with no other claims to fame than the number of wiki edits they pulled off. I think it was Marcus Aurelius who stated something like, "The opinions of 10,000 men means nothing if they don't know anything about the subject." That is exactly what wiki is. A classic example of the fallacy of the collective wisdom of 10,000 fools. And once again, that quote: "Seems PPM notation needs to be scrapped !!!" Really? Speaking only for myself, I think you need to learn the basics before you start recommending changes to the process of assaying. Have you ever needed an assay done? If I seemed a bit brusque, just consider it as a natural response to: "I think the general concept I am using is correct.." No "..., which I assume they are?." Assume? "..., as an example in the Wiki article with gasses, ..." Already covered wiki "Anyways, this is all rather academic.." Then why argue it? "..., is the analysis done as a molecular (mole:mole) analysis?" You don't know, but you already have an opinion? And finally, "It is well worth reading the wiki article on this.." To which I say, male bovine excrement. eric
  8. Strictly by weight, not mass density. 1 gram is 1/1,000,000 of a kilogram ergo 1ppm. eric
  9. Though I'm not a conspiracy worshiper, I do acknowledge that every participant in every market acts to manipulate the deal in their behalf. Nobody starts dickering by saying, "You need to raise the price by about 23% to get me to buy it." That being said, banks are in it for the money. When physical PMs are bought, the revenue stream stops. Ergo anything that a bank can do to convince people with monetary assets to avoid investing in goods that have durability will force the people to keep the money moving. It is called velocity of money and it has slowed substantially. UBS has perhaps signaled that the banks want gold to go not much higher than $1250USD and lower would be preferable. And the harsh reality is the mere jawing by the bankers will go a long way to forcing a self-fulfilling prophecy. Keep in mind that very few people are debt free and fewer still own substantial assets as well. Most folks are in debt past their gills and a large share of investors are highly leveraged. These folks desperately need assets to appreciate in order to cover their debt load. The UBS statement can go a long ways toward keeping folks out of the PM market. Low PM prices are a gift. Tis difficult to create generational wealth when prices are high. Might I suggest that folks download and read, "The Richest Man in Babylon" by George S Classon. It is free. The only significant difference between the time it was written and now is that gold is no longer the coin of the realm. However, gold is very desirable collateral. Why else would central banks be holding and in many cases increasing their stash? The miners will hurt from continued low prices, but a big share of that hurt was self-inflicted. Whether it is corporate, private or government, good times bring on a massive spending spree with borrowed money. Even relatively minor not-so-good times can make debt onerous. Extensive drops in prices for longer periods coupled with debt can and do wipe out even the greatest corporations. Does "Too big to fail" ring a bell? But then again, I am not an analyst, financial adviser or Prophet. Do your own due diligence. And as the poster on Agent Mulder's wall in "The X-Files" states, "Believe No One". Or the Latin phrase, "Cui Bono", who benefits? Do as you inevitably will. But no whining! 'I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself.' ---D.H. Lawrence --- eric
  10. Eric N

    Cleaning Contaminated Gold

    Better to have the acid at room temperature or warmer. Haven't used acid since the mid 70's in Oregon. Can't remember which, acid or retort, that left the gold brown in color. Melting it brought the natural color back. What I can remember is my youngest daughter (2YO) got into the nitric acid, got it on her hands and got a burn. The odd part was it was locked up in a foot locker. The stranger part is her older sister (4YO) got her hands washed off and then disposed of the acid. She wouldn't tell anyone where and it was never found. Be safe. eric
  11. I'm of the notion that any gold I acquire gets sold at market lows, taxes paid and then the remaining cash turned back into gold and silver coin. Why pay taxes at the market high when you get nailed for less at the low. The gold and silver coin? Goes into the generational wealth fund. The trick to acquiring generational wealth is minimal debt and saving discretionary monies in a medium who's value is difficult for others to manipulate. Although many complain about the manipulation of gold and silver, the harsh reality is that it is only possible while fiat money is the currency of the day. No fiat currency has ever lasted long. Some famous guy said something like, "Once the tide goes out, you see who is swimming naked." Then all assets will show their real value. What'cha think the paper gold bought with paper money will be worth? Read some history. Gold was the currency of kings. Silver for gentlemen. Barter for the commoners. Debt for the slaves. What was shall be again. Income generating property is another good place to store wealth. This can take the shape of a small family farm capable of growing the majority of your food. Food is production. Production generates wealth. Small mining ventures producing what is in demand is another. Woodlots produce firewood. The problem with rental property is the renter. If the renter can't pay, all you get is wear and tear, i.e. wealth depreciation. Same goes for companies. If the consumers are broke, no product gets sold. So celebrate the fact that Yellen and company can still play their silly reindeer games. Every day it goes on is another day you can put towards acquiring generational wealth. Why generational? It wasn't that long ago that our offspring took care of us in our older age. Why should they care if you are costing $5K a month in an assisted care facility? Oh. Don't look for interest rates to ever normalize. That would spell the end of this latest experiment in fiat money. Inflation would become so obvious that the government would be forced to use force against its citizenry. That influx of illegal immigrants in Europe is all about their gravy train was cut off. Nobody immigrates for political or religious purposes. It is always about the money. When the entitlements end, so does any loyalty. If your boss isn't paying, do you stick around? Read, Ludwig von Mises, "The Theory of Money and Credit". Some would say prescient, I would just say the obvious outcome of politics playing in the market. Not too difficult of a read, but lacks a glossary. Many of the terms are arcane to the everyday person such as fiduciary money versus credit money. But once again, be of good cheer. Have a beer and celebrate that Yellen and company kicked the can again. As long as the band plays on, we still have time to do what needs to be done. Für ich, I gotta quit this sniping nonsense and find a productive claim. At least my family has moved back and is taking over the mini-farm. Oh and they are learning the business of shaking a pan. C'mon Yellen. Just 8-9 more months. No doubt some of you have read about negative interest in some countries in Europe. That is good incentive to put your cash in something more valuable. Then there is the elimination of cash idea floating around. Another good reason to put whatever monies into durables. All of this is for controlling the interest rates. Interest CAN"T rise to any meaningful level or else the financial world goes out with a bang. Of course it will happen anyway. Only fools would believe this current iteration of fiat money managers are wiser than the last car full of clowns. Yellen and company know where this clown car is going. They are just trying to take the scenic route. The actual price of gold and silver is only relevant to those who depend on it for their revenue stream aka miners in debt. Everything else is just gambling. I have no pity for those who experience gambling losses. The house always gets its cut. And the wizards of the Eccles building spend beaucoup millions backing the house. As long as Yellen and company can keep the game going, the only choice we have is to take our money off the table. The thing about pecking yourself on the head with a sharp rock is that it feels so good when you quit. Maybe a little Ayn Rand, "Atlas Shrugged". Even Alan Greenspan admitted that, "In the extremis, gold is money". Kinda reminds me of that "Who's on first" routine by Abbot and Costello. Wow, that was certainly a long-winded ramble! eric
  12. Eric N

    March Issue Of Icmj

    I wouldn't worry about the nugget effect right now. Consider it as a pocket mine for the time being. Hand sort the better stuff to get a revenue stream going. My favorite reference for pocket mines is Tom Bohmker's book, "The Elusive Pocket Mines of South Western Oregon." eric
  13. Eric N


    Yah Chris, I'm familiar with the differences between melting and smelting. I was just curious about what happens to the electric element when someone cranks it up with a load of sulfides. Everything I've read says it can be done, but the element takes a beating and will fail a lot sooner than if the assay oven is used for the purpose of assaying. Was just curious if the differences in lifespan were that substantial. No Geowizard it does not weigh the same. 68 lbs red brass X 453.6 grams = 30.8 kgs @ S.G~ 8.56 68 lbs gold X 373.2 grams = 25.4 kgs @ SG~ 19.3 However had you stated gold ore, then you would have been correct. avdp vs avdp rather than avdp vs troy. If someone is gonna play the technical, then be prepared to get it back. That being said, obviously with the higher density and using troy weights, pure gold will always fit in the same volume that an equivalent poundage of other non-PGM material weighed in avoirdupois. Except the material to be refined is not SG~ 19.3 What if the material has an SG~5.5 ? Like mostly iron pyrite at 5.0 plus other stuff? Then it obviously won't fit in a #16 SiC crucible. ----------------- The question of course being either the required permits or the potential life-shattering fine for burning off the sulfides. Perhaps no problem in sub-kilogram size lots, but 20, 50, 100 lbs lots might attract attention. Sure wouldn't attract any sympathy from the community, local or mining. That videos show up on the web is NOT ample evidence that smelting sulfides in the backyard is legal in all jurisdictions. eric
  14. Eric N

    True Cost To Mine Gold - Companies Under Pressure

    C'mon Geowizard, it isn't an either/or situation. Both of you have valid arguments. A single owner/operator can tweak their operation and eat some of the expenses. A corporation answers to the shareholders. Oft times the Board makes decisions that a lone operator wouldn't. In the end, all expenses must be covered. However the lone operator just might write their living expenses off as said operator is going to eat, drink and be merry whether they are mining or sitting at home watching re-runs of "I Love Lucy". eric
  15. Eric N


    Other sources are Action Mining and Shor International. eric
  16. Eric N

    Low Level Heating Ideas For Mine Buildings

    If you are gonna be there every day, then consider using some thermal mass for heat storage and use a waste oil burner running hot to bring it up to heat. For thermal mass, use lots of rock and sand in a bin surrounding the stove. Make the bin out of salvaged sheet metal ducting. A buddy of mine worked in Valdez and they ran a waste oil burner at the shop. Running it hot resulted in cleaning the chimney every three, four weeks. Throttling it down forced a cleaning every few days. In one of my greenhouse I have a small vent-less propane heater needing no electricity. Locally propane is $21 for 4.5 gallons. Even though temps are just below freezing, I have to refill the 5 gallon bottle every couple three days. I would say not practical cost wise. Several years ago I got a small bunch of Healy sub-bituminous B and it held a fire overnight in my barrel stove. Only hassle was the amount of sand left over. Just don't let it get wet as it falls apart. Still, it's cheap and if it wasn't for the costs of transporting it, I would use it for everything. eric
  17. Eric N


    Admittedly smelting in outside my experience, but I have read a lot. One thing that struck me about the use of electric assay ovens and sulfides was the driving off of the SO2 which attacked the nichrome wire. Though the books said it could be done, it was recommended to not make a practice of it. Assaying only melts out 29+ grams at a time, which should be worth it as a smelter if you were getting a few grams of PMs per melt against the cost of replacing the heating element. But like I stated earlier, smelting is outside my experience. I just sell to the refiner and avoid the limited ROI of doing it myself. Comments? I get my nichrome wire from: jacobs-online.biz he also has a nichrome wire gauge/amperage/temp calculator online as well. eric
  18. Eric N

    Small Scale Prospecting

    Gambrinus Quit acting like a 14YO camped in your parents basement looking for something to post to Wiki. 38 posts and you have only been a member since 31 Aug 2015. You asked about drilling a 12"-16" hole in limestone. You got the cost-effective answer and then went on a rant. He could have just as easily suggested a single jack. Either would be an acceptable answer. I may not always agree with geowizard, but I've found much of his stuff usable. And though at times he irritates me, he writes for those who have little knowledge and experience. Your question about drilling indicates that you are among those who fit the above sentence. And when you didn't get the answer you wanted, you resorted to name-calling and arguing. A classic case of the ignorant arguing about what they don't know anything about. Are you a Democrat by chance? I was raised to believe that anything worth doing was worth doing right. That is still the mantra of deep pockets. I have found that anything worth doing is worth doing just good enough. It is through experience that one learns the difference between good enough and not good enough. Good enough is usually the most cost-effective. By the way, how have you contributed to this forum's body of knowledge? You asked a question and got an answer. Then you demean the person who answered your question. I can say with absolute certainty that I will not answer any queries posted by you. I don't need that kind of aggravation. eric
  19. Don't let folks dredge because it might harm salmon. Don't restore a watershed for steelhead because it might harm frogs. Has California gone stupid? http://www.adn.com/article/20150723/plan-ease-steelhead-barriers-stirs-concerns-about-frogs-little-yosemite
  20. Eric N

    Wash plant for mini excavator

    For the first step above a #2 shovel, I always though one of those tow-behind mini-backhoes might be the logical answer. From my reading, it appears the buckets are about 1 cubic foot with digging depths to 7'-8'. Looks to have about a 2-3CY capacity per hour. Small gas engine so it sips fuel. Well under $10K brand new. Haul behind a pick-up or on a reasonable trail with a 4 wheeler. Lots of plans out there if one wished to build their own over the winter. Which could be good from the standpoint of knowing the machine when it comes to maintenance and repair. But here comes the caveat. I have no hands-on experience with the concept. And that is the problem with book education. Looks good on paper, but can fail in reality. eric
  21. Got a few opinions, but no experience to base those opinions on. I imagine you are correct about the cost factor. I just know that sluices are really cost effective. I doubt that a jig would work on the size of gold found in sand deposits. The others are probably quite cost effective once scaled up to some minimum required feed rate. You said this was a fossilized sand placer. Is it sandstone or just sand glued together with clay? Maybe you should determine how many yards you can move in a day and what your budget is. Then decide from there. I'm thinking at least 1 and maybe more inhabitants of this website had dreamed big once or twice their own selves. Okay, it was me. eric
  22. The problems you will run into, in no particular order, are: The gold will be real small. The larger gold and consequently heavier dropped out amongst the pebbles and cobbles upstream. By small I mean mostly -100 mesh and down. This presents a bit of a task to accomplish a high percentage of recovery. Then there is the shear volume of material that must be run through the sluice. All of the material must be slowly fed into it or you will plug the bedding resulting in more recovery loss. Rather than being able to classify out the obviously not-gold, you will have to sluice it all. Then there will be all the tailings that come with the garbage in, garbage out process. The above demands will require lots of water and a monster width sluice to process. Can it be done? Sure. Economically? Maybe. If you look at the Keene Beach Box, you can see that it is a lot wider than their other models. It is this wide just because it was designed to run sand and still be small enough to be portable. Hope this helps. eric
  23. Over the last decade or two, I've begun studying, building and using metal detectors. The first thing I learned is everyone seems to have an opinion and most are questionable. So in a fit of irritation, I started buying books. Guess what? Most are just opinions as well. However, ... Carl Moreland and George Overton, long time denizens of the Geotech website and MD designers in their own right wrote the book, "Inside the Metal Detector." Not only does the book cover theory, but design principles and actual projects as well. But again, the principal mechanisms presented have their own biases built into the explanations. So here is my take. ALL MDs use the same basic principles. Emit an magnetic wave which induces eddy currents in the target. Then compare the magnetic wave re-emitted by the target against the magnetic wave emitted by the detector. That's it. Compare after target with before target. MD coils are NOT, I say again, NOT antennas. So for all practical purposes, forget about radio waves. Think strictly magnetic. MD coils are just one side of a transformer. Now we have to consider the detection methods. Unlike so many others, I content that there are three detection methodologies: Frequency domain, time domain and phase domain. In frequency domain, the target affects the frequency. Think of it as frequency shift. I count two different types of detectors that use this method: BFO and Loaded Loops aka Off-resonance. In the BFO, the target pulls the transmitted frequency and you hear the difference of the pull when it is compared to a stable oscillator. In the Loaded Loop, the target pulls the transmitter either into a filter pass-band or away from the filter pass-band. This pulling of frequency is due to conditionally stable oscillators using coils that have the coil characteristics (inductance) changed by metal getting within the coils area of influence. Altering the inductance changes the operating frequency. In time domain, the re-emitted signal changes the decay characteristics of the soil. By shutting off the transmitter and coil real fast and then sampling, any noticeable change in the decay can be detected. This is the realm of Pulse Induction detectors. Stability of the oscillator is absolutely mandatory. Then there is phase domain. In phase domain detection, we look at how does the target change the phase relationship designed into the detector. Regular electricity is single phase 60 cycles per second. In industry, where there is a demand for far more power, we have three phase 60 cycle. There are three separate waveforms going down the wires with each 120 degrees out of phase with the others. In phase detection MDs, the coil and electronics are designed to accommodate the difference in phase relationships between emitted and the re-emitted signal from ground. Any conductive target will alter that phase relationship. That phase difference is measured in degrees: plus or minus. Among the phase domain detectors we have T-R and IB. Stability of the oscillator is once again mandatory. In the T-R detector, we have a carefully phase balanced pair of transmitter and receiver. Each has a separate coil. Any conductive mineral will unbalance the system. These detectors are often called two-box and were used for surveys. Most are now airborne and much more complex. This complexity is at it peak in the IB detector. It uses the same principles as the T-R, but adds discrimination. So how does it add this? Remember that phase relationship and how it can be plus or minus a few degrees? That is the key. You compare the emitted against the re-emitted in both short-term and slightly longer. The ground doesn't change much in the short-term while a target does. The ground changes slower and this is compared separately and alters the ground balance. There is no change in frequency, ergo T-R and IB are NOT frequency domain detectors. Now here it comes just because I'm old and cantankerous. You WON'T learn doodley squat from reading about detector theory on some website. It will only confuse you more. If MD theory really appeals to you, buy the book. Read it, do the experiments and build the project MDs covered in the book. You might wanna lurk for awhile on the Geotech forums. Do NOT go there if your sole interest is using detectors. It is the hang-out for designers, builders and flat-out unusual characters with odd ideas. Such as mine with frequency, time and phase domain design characteristics. There is nothing mysterious about MDs. Once you learn the theory and gain experience building with electronics, you will notice that excellent MDs can be home-made. Technically speaking, magnetometers and gradiometers are MDs. They detect a localized shift in the earth's magnetic field. Once again, it is ALL about magnetism. In using mags, there must be two mags in operation. One is the reference that logs the changes in the earth's magnetic field throughout the day while the other is the sampling mag that gets carried through the survey zone. In gradiometers, there are two mags that compare their readings. Both mags are separated by a few feet and the one closest to the iron target, remember this is about magnetism, detects the localized shift in the earth's magnetic field before the one further away. No separate reference magnetometer is required because this is only a comparative detector. Comparing here with back there. Or in cases where the gradiometer is used in vertical mode, here with just up there. The key to understanding all this is forget everything you think you know about radio. This is about magnetic fields. Yes, there is an accompanying electrical field but it isn't relevant. Hope this helps a bit. I'm still learning and have a long ways to go before I can claim any measure of proficiency. First, last and always, it is all about magnetism. Induced or natural. Oh and just a friendly aside. College doesn't teach metal detector theory or design. My electronics training background was military. Even it was awful weak. Fortunately the technical manuals covering each of the military MDs was quite well written and at an 8th grade level. Nuf said. This isn't the best forum for MD theory and design. And I admit that I am pretty much a novice. Try Geotech. It is where I go for answers. Just be aware, they ain't gonna hold your hand. So you better get familiar with the website's search function. Hope you got the idea that I'm done with this thread. I presented it only for information purposes only. eric
  24. Eric N

    Ac To Dc Converter

    Standard DC motors can handle over-voltage pretty well. As an example, many farmers converted their old 6 volt tractors to 12 volt and kept the 6 volt starter. Where DC motors run into serious problems is under-voltage. The motor will attempt to provide the required power but at the cost of increased amperage. Go too far under-voltage and the amperage increases beyond the capacity of the motor's wiring capacity and the wire melts. This is the reason for using fuses sized to the load. Typically any motor that was built for 12 volt vehicle use will run just fine on a battery charger. Starter motors excepted as they were designed for intermittent use; start the engine and then shut off. Windshield washer motors tend to be the most dependable and they come with a gear reduction unit built in. Bilge pumps are as handy as pockets on pants especially for re-circ operations where the water is substantially less than potable. The cheapest and easiest power conditioner is a 12 volt battery with an amp/hour capacity equal to the load. Even an old worn out car battery will work good enough. Just remember you are dealing with battery acid and hydrogen gas when using standard batteries. I don't recommend SLA batteries. Higher cost, shorter life and lower amp/hour capacity per weight. eric
  25. Last year I was able to get a copy of Karl von Mueller's "Vibrating Gold Concentrators" through the inter-library loan system. I think, just think due to little experience with dry placers, that the concept bears further testing. Basically think of his idea as a sluice with a vibratory sander mounted underneath. The riffles are standard but not too high (think as high as the gold is in size). The slope is modest. The vibration must be strong enough to keep the material fluidized. Higher SG material sinks into the space between the riffle and the lower SG material flows over the top of the riffles and down the sluice. Because of the low vertical energy component, dustiness is minimized. A small, localized, dust cloud in the middle of nowhere draws attention. To increase the capacity, I thought of the basic 1st layer of a Reichert Cone concept. Feed classified material into the center and have riffles diametric all the way to the edge where the light SGs drop off. The cone becomes a tapered, all the way around, sluice. With the increasing diameter, you get riffle capacity. It'll hold a lot more of the higher SG material resulting in fewer clean-outs per operational period. How to feed and classify? How about an upside down cone with the near center screened and the very center a larger diameter plastic pipe feeding the oversize downhill and off the structure. Same vibratory used for the cone sluice and the classifier. The feed could just as easily be a conveyor. Even as basic as something along the lines of the Sam Radding design. For power? Why not electric? Several economic and quiet generators on the market. Will it work? With tuning, I think so. Something beats the snot out of nothing. BUt I say again, I have minimal experience with dry placering. eric