Recovery of fine floating gold

A. Dan:

I have done quite a bit of dredging with a 3 inch in the past also. I've never run into floating gold, but have run into flour gold. The stuff that is so fine you cannot pick it up or even see it but it is there. It is definitely worth recovering. But ... you will have to use mercury to extract it. My father in law had a 12 inch dredge that he would take his black sand and put it in a cement mixer with a quart of mercury. Mix all night, get the mercury/gold amalgam out and retort it down. This is an especially cautious area as the mercury will put off fumes and vapors that can really mess you up. On a small scale you can pan your black sand down to a hand full and add about a dime size amount of mercury in the pan. You will soon see it take on a gold color as you continue panning. Once you'er sure you have all the gold recovered, remove the mercury and put it in a small crucible. OUTSIDE and with a fan blowing the fumes away from you burn off the mercury from the gold. You will have to use a oxy-acetylene torch to do this. You will be left with a button of gold. My father in law used to pour the molten gold into a big container of water and would pull out a beautiful drawn out nugget that he would make into jewelry and sell. As I said before. This is not to play with and realize the hazards of mercury. You may want to just use the mercury to extract the gold and then let someone that is experienced in extracting it do that part of it. Good luck, keep your feet dry and don't let anyone throw a piece of shiny scrap brass in your sluice box! (not that I have done that to others) ;) Tom

A. One response was to burn off the mercury. This true but very dangerous as the fumes are deadly. They can cause loss of teeth, gum bleeding, hair and extremely intense headaches. If burning off mercury, place the amalgam on a shovel, cut a large potato in half length wise, gouge out a small area in the potatoes center. Place the potato over the material to be heated. Heat until all mercury is gone.
Place the potato in a small container of extremely cold water and most of the mercury will resolidify and come out of the potato for reuse. I used this method at Lake Isabell California back in the 70's when sluicing.

Best of Luck.

John Pavelka
- San Antonio, Texas

For God's sake DO NOT use mercury to extract your gold. If you are lucky enough to not breathe any of the vapors, you are still dumping it to the atmosphere and your neighbors downwind will be breathing it. To use mercury nowadays in mining is highly irresponsible. Here is what you do:
Dissolve the fine gold into a chlorine bleach ⇦ bleach/sodium hypochlorite in bulk on eBay or Amazon [affil links] solution or into a solution of aqua regia and be sure to use eye ⇦ on eBay or Amazon [affil links] , hand ⇦ on eBay or Amazon [affil links] and lung protection ⇦[this on eBay or Amazon [affil links] and do it outdoors. Then raise the pH with lye ⇦ on bakieBay or Amazon [affil links] (sodium hydroxide) and the metals will precipitate out of solution as hydroxides. These metal salts can then be placed in a covered crucible in a furnace and burned down to the metallic metal which will hopefully be mostly gold.

I would post some links here on the exact procedures, but links are not allowed. You can also trap the dissolved gold on activated charcoal and then burn off the charcoal.

Jeff Sargent
March 3, 2008
- San Marcos, Texas

Ed. note: Thanks Jeff. Links are not 'disallowed' but they are discouraged because almost every link breaks in short order, whereas our goal since 1989 has been to build *permanent* technical pages which will prove useful & informative for years to come. Google is for links.
Old links get sold to link farms (spam); but worse, hackers buy up old links and put malware on them, counting on readers to trust the link because the link is on a legitimate sites like ours -- leaving us with whack-a-mole constantly re-checking 250,000 postings going back decades. If you offer a link, please summarize what the link says and give the title of the article so it can be found when the link breaks -- which they virtually all do and very quickly. Thanks!

A. To Jeff,
The amount a mercury vapors that would be diluted in the air for said downwind neighbors is far less of an impact than the very harmful gasses given off with chlorine and lye. Not to mention that unless your neighbor is in a close proximity, most of the mercury will fall out of the air due to it molecular weight. The chemicals that most people use in their homes have far worse repercussions "According to California".
www.prospectorsparadise.com/html/mercury.html ⇩

Kelly Trumble

Ed. note: As we we *just* finished warning readers, DON'T FOLLOW THAT LINK! Thankfully, Internet Archive preserved a copy of what used to be there
These days information often appears on the internet, then disappears forever. If that is a concern to you please consider a donation to The Internet Archive.

A. Take a potato, cut it in half. Dig out a dime-size hole in one half of the spud, put your dime-size blob of mercury in the hollow in the spud. Wrap spud in tinfoil. Bake spud under coals, downwind (just in case).
Open spud, collect gold. Put baked spud in your gold pan and pan out the mercury.
Do not eat the spud !

Multiple threads merged: please forgive chronology errors and repetition  🙂

A. Another method using mercury is to let the mercury pick up the fine gold in your pan, then pour the nickel size drop of mercury amalgam into a small depression created in an old t-shirt. Squeeze the mercury amalgam through the t-shirt and collect your now cleaned mercury in a glass or pyrex container. Cut the dirty brown spot out of the t-shirt as this is now your fine flour gold adhering to the cotton t-shirt material. You can burn out the t-shirt
material to make your gold button or even use nitric acid solution to dissolve the cotton material and leave outside in well vented area to evaporate, leaving just the fine gold.

A. It was funny that I found what you wrote because I was looking for a solution to the exact same problem. I have an almost dry well on my property that I use for irrigation when watering by hand. 2 days ago I discovered black sand and fine gold in the bottom of the bucket it is so fine some of it floats. Being completely new to the subject I called a local gold mine and the man there told me there are plenty of different equipment out there but he recommended to let it dry and use series of different fine meshes to screen it through; he also said it was very time consuming but usually worth it.

A. I know that either hard water or soft water will make gold more apt to float. (I think it's the hard water)

I found this while trying to find a solution to the same "flour gold" problem.
I saw a old timer on the GPAA tv show saying dish soap would make the surface tension break and cause the floating gold to sink : )
It wouldn't be a good idea out in a stream with a dredge, but he was running his operation at home reusing his water and bringing his material home to separate the gold

A. The gold floats because of the surface tension of the water. In a small recirculating operation you can use Jet Dry [Jet Dry on eBay or Amazon [affil links] or dish soap to break the surface tension and the gold will not float anymore. With a dredge, as long as you don't bring the gold to the surface, it shouldn't float. Maybe a deflector to keep it down in the sluice might help. Good luck

Bluebowl Concentrator

on eBay or

Amazon

(affil links)

A. I don't know if this will help your situation, but there is a product on the market for retrieving fine gold from black sand. It is called Blue Bowl Concentrator ⇨
It's made by: Pioneer Mining Supplies, Auburn, Ca

A. Dan L -- you are looking for a fine gold recovery system ?

Buy you a 8 inch piece sch. 40 pvc pipe and a glue-on cap. Drill the cap and screw a water valve into it, this is so that a hose pipe can screw onto the valve. Buy some ribbed rubber matting to bed the full half 8 inch pipe. from the cap move down about 12 inches and cut the pipe in half long ways. Find a tripod , like the one's used in surveying, drill a hole for, and install, a carriage bolt in the pipe in the middle. use a wing nut to mount the pipe to the tripod. You can adjust the tripod to most any height or angle. You can run a hose pipe from the dredge to the pipe and the valve will adjust your flow. If you adjust the angle right you WILL recover all gold no matter how small. The 8 inch pipe gives you a good wide bed for gold to hangup. One person can run the pipe while the dredge is being used. You will love this fine gold recovery system. This is all I ever use with my 3 inch dredge.

A. I've been getting into flour gold and found that vinegar ⇦in bulk on eBay or Amazon [affil links] works well to make the gold drop over a short time frame.

A. Classification is the key no matter what type of recovery system you use.

A. I agree with the person that suggested separation. Get a button up shirt that you no longer wear, use a 5 gallon bucket and cover the opening with the shirt and tie the shirt around the edge creating what looks like a drum. Now put your fist into the shirt slowly to create a funnel inside the bucket. Make sure the t-shirt will not cave in or you will lose all the gold and have to start over. Make sure you drill holes in the sides of the bucket so that the water will drain out when it starts to fill up. You have just create a big sieve. Stir up the floating gold and pour it into the sieve. When you are done just bunch it up and dry it. Save it until you are ready to process it into a nugget. Do not attempt to refine the gold unless you have experience, I've done it with proper supervision and coaching. What you have in the t-shirt is a mixture of all kinds of material not just gold, do not go and burn it without the proper setup. Make sure you check the drainage water from the sieve to make sure there are no holes and the shirt is catching what your going for. Have fun. Use a battery operated water pump so that you can just stir the gold up and take down a beer while everything is running. lol Good luck

A. Use a large coffee filter or you can buy large sheets of material that they use for tea bags on the net.

That will filter the floaters out of your water and also using a fine miners moss or outdoor carpet in your box will pick up most of the fine dust.

I use to just tie a black bandana to the top of a bucket and pour my recirculated water through it at the end of the day and it worked pretty well.

A. I recently learned of a fella in Colorado who has discovered a safe way of gold recovery and they have been working on refining the process since April 2008. Search "Amalgamite". Very interesting. I have yet to try it. Came by here in search of what electronic parts might be worthy of salvage. Thank you.

I haven't seen anything here that will collect enough gold to cover the head of a pin.
Float gold cannot be recovered by any of the above. If you want to recover float gold you need very fine mesh bags (can be found on the Internet under water filtering). You pump water thru the bags for several hours. Not all water will have gold. Only the top 2 to 3 inches and must be below a waterfall or behind a dredge.

A. Floating gold can be settled by breaking the surface tension with a surfactant "jet dry" [Jet Dry on eBay or Amazon [affil links] comes to mind. Back in my youth we used to play with a Shaklee product called "Basic H" it was a wetting agent that would make water wetter and break surface tension. Most of the agents I can think of would work if you could drop small amounts in your sluice box as you run.

Good luck and hope you always see color in your pan!

A. I've been working with some flour gold and have found a good way to get it out of sand. It's called a door mat.Yes I said a door-mat! The mat I use has a fine texture on it kind of like miniature creek beds. run it the same way as you would run your regular sluice. Carefully control the water flow and down angle. If you want large gold think big! But if you want to get the small gold out think small.

A. The gold don't go through the mat it sits on top. gold is flat black sand is round. this is why the sand runs off and the gold sits down on the mat ... however some gold flakes/the larger flatter ones might get washed down no matter what you do. Just set your water flow and angle. Keep testing small amounts till you can see the gold settling and the sand running away. I usually run sand with a table spoon, spooning it onto the mat but like I said it's a slow process.

A. The best deal to recover find gold is to reduce the depth of your flow and make it free of turbulence. Any riffles or obstructions must completely be covered by water. There is a formulaic way to figure out exactly how many gallons to pump to do this, but suffice to say with a 6 inch wide sluice running 1 inch deep, at a 5.5 degree angle you need 40 GPM feed water. Amazingly, if this sluice would clean immediately it would handle 5.3 thousand lbs of fines per hour, and twice that in gravels, at least. Of course it is unlikely that a sluice fed this much dirt would clean it in the same time. You need fast moving water to clean a sluice quickly, at least 4-6 fps. A 1.25 in. deep sluice at 10 inches wide at a 10 degree slope would attain 3.5 fps, but it needs 132 gallons of water per min to attain that flow speed. At that speed you would need lots of sluice length and nomad carpeting to recover fine gold. (15 feet?) You need to screen out everything over 14 mesh in sands to ensure good recovery. While you see lots of sexy ads on youtube etc, what they don't tell you is that river water running through the sluice is hundreds of gallons per minute. (300 GPM or more for a 3 inch depth of ten inches wide at 7 degrees - 6 inches in 4 feet.) Just because you see some fine gold after clean up tells you nothing about what you missed. Just because the first 1/3 of these sluices recovers 90% of the gold in the sluice tells you nothing about what 100% was in the original dirt. It merely says that the back 2/3s recovered 10% of what it got, (this was fine gold) -and- if it recovered gold right up to the end, that was where it was losing fines. Getting less and less does not imply there was less and less. Just that was the efficiency of the sluice.

The best kind of sluice for fine gold would use semi circle indentations in the sluice bottom, rather than riffles, as this has less turbulence and obstruction to flow. (Gemini table is an example. Riffles should be no more than 3/4 the height of water flow depth. You should not see white water or frothing in the flow. No chemical or flocculants should be added to a sluice, because a sluice needs surface tension to clean properly. If gold floats on ST, then it is more or less lost. The volume of even acres of this type of gold is so minuscule that it is well worth ignoring. It is seen in many placer or gold productive areas, especially where the water has tannic acid s in it, or pine oils. It would be very tricky to add just the right amount of detergent not to defeat your sluice and to recover significant quantities of gold. You could experiment with Loc from Amway [Loc on eBay or Amazon [affil links] , but be careful as it is very powerful as surface tension remover and may actually hinder gold recovery if too much is added. What will adhere to a pin will remove all the ST from one liter of water.

It is possible to recover very fine gold with what is called an undercurrent sluice. All the undercurrent does is provide slits in a false bottom running lengthwise with the sluice current. The slits themselves are much less in area than the screen bars of the undercurrent itself. Sort of like a sieve bend. The descending water into the slits of the sieve takes mostly just extreme heavies and has a tendency to reject the lights. If the sieve areas are made just right for the flow, the concentrate so collected will be fairly high grade. It helps to narrow the sluice by about half at the point where the bar-screen false bottom is set, so that the feed naturally stratifies and the bottom becomes a heavy layer, which is scavenged by the undercurrent. A flat bar width of 3/16 inch with a slit of 14 to 18 gauge would be workable. Make the bars about 12 to 18 inches long. Several of these in an 8 foot run should do the work you need.

I have several other designs I have tried on ultra fine gold (20 to 50 microns or 8 ten thousands of an inch to 24 ten thousandths of an inch. Throughput is ultra quick and all you get is gold. Good for cleaning Black sands. I am a little bit coy about design details.

A. I read that they use a flotation plant that uses a reagent that promotes flotation. Air is pumped through a conditioning tank and the gold and silver bubbles up and it is run through a carbon filter then processed.

A. I mine for flour gold in Juneau, Alaska. We use Gold Hog yukon mats, Dawn dish liquid, and a 3" hydroforce nozzle. We pump well above 20,000 gallons per hour. We have 2- 12' sluicing setups and we often combine units for a 19' machine. No matter how finely tuned your setup is, chances are you will not catch all of the fine gold. Any way you can cut down on bubbles in the system, and cause the gold to fall out of solution will help. We mine almost exclusively the super fine gold, so catching as much as possible is obviously our objective. We have added everything from thick bristley mats turned upside down, to rocks in the header box, and miners moss barriers. We move an average of 10- 12 yards per 6 hr shift, as we are only allotted a small window of work time, due to the tide.

A. Hello Melissa, Sounds like your dog has the Midas touch! Not to burst your bubble but you could have iron pyrite there, aka fools gold. Iron pyrite is magnetic, as gold is not. If you have enough surface area you can test it with a magnet. Another simple test is to rub the area in question well. Iron pyrite has an odor of sulfur, or rotten eggs, gold does not have a distinctive odor. It is possible to find gold in rock, not very common in fireplace stone however. Is it worth pursuing? I would hate to see you ruin your fireplace for such a small amount of gold. Let us know what your findings are. One more thing, that's one tough dog you have there!

A. Could be schist, in which case the dust is mica. Could contain pyrite (an iron compound known as Fools Gold), or Galena (a lead compound- but it's more silvery). No point in pursuing it- Even if it WERE gold, the cost of recovery (dismantle, break up rock, smelt, rebuild fireplace) far outweighs any tiny amount of gold you might find. It's about $40/gram, how much does a new fireplace cost? Pics of the stone would help narrow down the possibilities. I'd be more concerned with your dog needing to break that habit before he ruins his teeth- Mine was a rock chewer too and I'm not looking forward to his dental bills when the damage starts turning into cavities.
If you've actually got gold in your fireplace, I'd say it's more valuable as a conversation piece :)

A. Hi Chad,
Can you try polyelectrolyte to settle fine gold powder?
Thanks.