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a few questions


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What would happen if you melted down gold and it had black sand, or any kind of sand, in it?

How do people process the tiny flakes? I've been using a spiral wheel, then panning, then using a magnet, but I'm having trouble getting it 100% clean -- what's the best way to do that?

What do people do with all of the fine flakes?

Thanks,

Jean

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If it behaves like lead, the sand and other impurities will float on top of the gold. Some times a flux like borax helps.

The really fine gold was what prompted miners to use mercury in their recovery efforts, something that is discouraged these days.

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Jean, please do not use a magnet. Wet or dry, the gold will get locked up in the magnetite black sands and you can loose it.. There`s a better chance of this happening when wet, but it will happen with both methods. Its not worth the trouble. For ultra fine gold , mercury will suck it up. For small pickers & flakes, just some panning practice may be in order. It can be a daunting effort sometimes. Panning skills are handy when recovering gold.

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Depending on the amount of black sand, a Miller table will recover -100 mesh gold, but the miller table only works a couple of spoonfuls at a time so won't do much goof for buckets of black sand. Refining would definetly work, but when I looked into it, it is expensive and looked like it processed a pint or quart of material at once and still wouldn't pay for the gold I'm getting out of that amount of concentrates.

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How tiny are your flakes? gold is still visable at several hundred particles to the dollar so you may have reached a point of practicality. Save all of this final concentrate while you learn how to safely amalgamate gold or find someone to do it for you. Have fun-best of luck.

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Depends on how many fine flakes we are talking about...

If your taking about trying to get the black sand from gold and your working with 1 shot glass of materal. I'd say stop wasing your time and get more material.

Eventually you will have a bucket of black sand and they you can screen it to the same size and then work to get as many fine flakes out with some success.

Unless your trying to separate an amount of gold tht have a real value. It really not worth your time. Or mine for that matter,

The area I work for gold will easily give me 2-3 dollars a day in very fine gold . I am very lazy and panning the material to get that is a total waste. But keeping it in the bucket after I drywash it for several trips will eventually be worth running it back through the dry washer and then panning that down to get a better amount of gold out of a pan of material.

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These were all really helpful tips, thanks everyone.

I guess I'm concluding that it's not worth bothering with this tiny stuff until I have a whole bunch, so I'll just keep setting it aside for now. Maybe by then I'll be finding massive nuggets and won't care - ha!

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With the caveat, if you have the time & patience, BLUE BOWLS, do a fairly good job of fine gold recovery.

I don’t use them, as they are not cost effective for running the amount of material on the scale I recover.

Personally, in a placer operation with a lot of very fine gold. I simply do more wash plant sluice box clean ups, more often. Recover the larger easy heavy gold, save the con’s that contain the very fine gold. Then run those through a long narrow clean up sluice without riffles in it. I use rough top or tiny ribbed top conveyor belting in the bottom of a clean up sluice. Material you run through a clean-up sluice is classified very fine anyway. So clean-up sluice angle & water velocity does a good job of separating black sand from fine gold along its length.

It only takes a one foot wide length of sheet metal, 8 feet long to built a clean-up sluice. 4 or 5 inch bottom width & 3 or 4 inch side walls. Any decent sheet metal shop will have the gauge metal you prefer & for not much money, bend it on a sheet metal brake to the bottom width & side wall spec’s you want.

In a clean-up sluice 8 feet long. Only run about 6 feet of belting on the bottom. Leaving a 2 foot long SLICK PLATE area on the head end of the box. Doing so allows the concentrate feed material to stratify in the slick plate area, before entering the belting gold recovery area. In flowing water, the heavier material naturally moves to the bottom of a stratified flow. Gold particles on the bottom of the flow, will naturally drop out faster than material higher in the flow, thus are easier & quicker to catch at the head end of the belting.

A narrow clean-up sluice doesn’t require all that much water to run effectively either. So a pretty small pump will do the job fine. If you have a “Y” or “T” & valve in the water supply hose feeding the header end on a clean-up sluice. Attach a garden hose there, to use anywhere in the box, to add a little more water directly where the fine gold settles out, to help wash the black sands away & further down the box. Resulting in a line of separation between black sands & fine gold particles. As always, it takes trial & error tweaking to get it set up & running right for optimal gold recovery.

Assuming you are doing this on a hobby scale, building a small JIG set-up is probably beyond you.

But, it’s worth mentioning because a JIG does a better job of fine gold recovery than a sluice box.

Sluice box riffles have inherent metallurgical limitations. The gold must settle and be trapped behind the riffle in a swift current of water. The current's velocity must be great enough to transport crudely classified material across the riffles. The slower the velocity the better the tendency for the gold to settle and be saved. This lower velocity, however, has less carrying capacity and will allow black sand and other heavy minerals to pack behind the riffles leaving no trap for the gold. If the amount of water and the slope of the riffle are increased to provide sufficient velocity to clean the riffle, gold particles that were previously trapped will be remobilized and lost. Sudden surges in feed may also dislodge gold. If the velocity is too low during the down cycle, black sand will again pack behind the riffle. In either case the first gold lost by the riffles is presumed to be the fine (- 200 mesh) gold. Tiny particles of very flat foil like gold because of its poor setting ability will also be lost.

Jigging avoids these limitations. The best can be adjusted to permit settling and trapping of the gold at all times. Once trapped, the gold is removed from the stream and the losses from packing and surging are eliminated. The jig can be adjusted to remove a large percentage of black sand and the balance can be eliminated on tables or further jigging. The pulsations of the jig move material across the jig to the tail, and consequently, less water is required to move material. Conditions at the top of the jig bed are quiescent at the top and bottom of each stroke. This provides a better opportunity for the gold to settle.

http://mines.az.gov/Publications/circ052jig.html

http://graymfg.com/mineral.html

Edited by elder-miner
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It is always a good idea to add a bit of JetDry to the water you use to pan or any wet processing of concentrates. I have found it makes a big difference.

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Thanks again, you guys are da best!

Elder-miner, I appreciate the detailed reply. The jig is out of my league, but a clean-up sluice as you describe looks not too hard to put together.

So, lots of good options to consider. I got some jet dry and will play with that in the pan, for starters.

Jean

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Heck, alot of us here have blue bowls and such, just save your concentrates and let me know and you can run them through mine. I can't speak for others but I'm sure I am not the only one that would extend the offer. I understand some people don't get out enough to justify so much equipment. Anyhow, just a suggestion. You never know, you might find new folks and new places to dig. Good luck

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