black sand concentrate extraction

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Laz777

Member
Joined
Apr 28, 2011
Messages
8
Hi everyone,
new to this forum, found it through a member's youtube vid.
I do some small scale placer mining in northern California and have a question.
instead of giving my black sands back to the river, is there any cost-effective way of recovering the micron gold it contains?
and a tougher question: how much can I expect to recover, say from a gallon volume of dried magnetite where there is no visible gold present?
I know there are a lot of variables in my last question.
one more though: is using mercury to make an amalgam viable and/or legal?
thanks
 
Laz777 said:
Hi everyone,
new to this forum, found it through a member's youtube vid.
Hello Laz,

Welcome to the forum.

Laz777 said:
I do some small scale placer mining in northern California and have a question.
instead of giving my black sands back to the river, is there any cost-effective way of recovering the micron gold it contains?

Crushing and leaching would be the best bet.
Smelting to lead, and processing that would be your second option.
Both have a cost factor, so my suggestion is to have your "Black Sand" assayed, and sell it based on the assay.
I do have market contacts, so that is an option, if interested.

Keep in mind that black sands often contain Palladium,
at least that's been my experience with the black sands from my area.

Laz777 said:
and a tougher question: how much can I expect to recover,
say from a gallon volume of dried magnetite where there is no visible gold present?

No easy way to tell, short of a Fire Assay.

Laz777 said:
one more though: is using mercury to make an amalgam viable and/or legal?
thanks

It is viable, and legal, but unsafe if you don't know what you are doing, so study up first.
In my thread, "GoldBug University", I should have a post on prospecting that includes how to use amalgamation as a method to recover fine, and micron gold from crushed black sand.

I hope that this has been helpful.

Sincerely, Rick. "The Rock Man".
 
Richard36 said:
Keep in mind that black sands often contain Palladium,
at least that's been my experience with the black sands from my area.

Helo Richard.
Can you add some numbers (ppm)? I have access to some black sand in gravel with some gold (max. 2g/t of gravel, source of gold is houndreds of miles northern), but dont know about palladium or how much black sand/1t of gravel. How much Pd in 1 kg of sand is marketable? Can a profit be made?

Oh, I have a question about assey. How much sand is needed for one normal assey?

Greetings, Simon
 
thank you for your reply Rich.
I suspect that it wouldn't be cost effective, but it just bothers me that I know there's some gold that can't be recovered easily using the usual methods most artisanal miners use (clean up sluice, blue bowl, wave table).
I'm new to prospecting and have heard many things that seem to be "miner's talk" (i.e., BS).
most of my prospecting has been on mainly the south fork of the Yuba and the north fork of the Feather.
placer fines command 70-75% of spot currently in the area, though I've been paid as much as 80.
one regular buyer of mine dropped from 75 to 70, due to the wild fluctuations in spot in the last year.
he's told me the local native gold assays to about 83% (20K) and coupled with the pricing variables and smelting fees, that he's taken a few hits when the price dumped. sounds reasonable, but he doesn't raise his rate when the price is back on the upswing either.
I have run across what I believe to be a small amount of platinum, which of course would contain a trace of palladium.
anyhow, I have much to learn, glad I found this site.
 
dorki22 said:
Richard36 said:
Keep in mind that black sands often contain Palladium,
at least that's been my experience with the black sands from my area.

Helo Richard.
Can you add some numbers (ppm)? I have access to some black sand in gravel with some gold (max. 2g/t of gravel, source of gold is houndreds of miles northern), but dont know about palladium or how much black sand/1t of gravel. How much Pd in 1 kg of sand is marketable? Can a profit be made?

Oh, I have a question about assey. How much sand is needed for one normal assey?

Greetings, Simon

Hello Simon,

I don't have any numbers in ppm for the sands from my area, and even if I did, the values differ greatly from area to area,
so an assay would be necessary to determine those values within the sand that you have access to.

29.16 grams is all that is needed for an assay,
but I always ask for at least 4 ozs of material for any assay that I do on Ores.

I would suggest an ICP for your sand in order to determine how much palladium it contains.
I do not have ICP equipment, so I can't do that assay for you.

The best that I could do is to do a fire assay, collect the bead, if one were present, and send it off for ICP.
In short, and ICP analysis of you sand, or of a bead collected by Fire Assay would be the way to go.

After getting those results, I could figure out approximate value, and help find a buyer for it.

Sincerely, Rick. "The Rock Man".
 
Laz,

Put some PVC tubes with 1/8" holes drilled within them, and capped on one end in an old bath tub, then connect those to an air compressor. This is your churning device. Fill the tub 1/3 of the way with water, and add 1 lb of sodium hydroxide. to this solution add your black sand, turn on the compressor, and let run for an hour or two. This will clean your sand, and strip some base metals. Short of this, you could crush the sand to twice it's starting mesh.

If using the tub method, drain the wash water into another large plastic, glass, or ceramic basin, and wash the sand with tap water for 15 minutes to make sure that all the Sodium Hydroxide has been removed.

Now take the washed, or crushed sand, and proceed to amalgamation by placing the sand in a concrete mixer with a couple table spoons of mercury, and let it churn for 24 to 48 hours, then run the sand through a "Blue Bowl to recover the mercury amalgam. Process as stated in my post under "GoldBug University".

Short the Concrete Mixer, you could wash the sand over a copper plate covered with mercury to capture the fine gold,
then scrape off the mercury, and process it as you would the mercury recovered by using the blue bowl.

Scrap Metal in a concrete mixer with the water, sand, and mercury works reasonably well to crush the sand,
as well as amalgamate the gold from it, all in one step.

Just some thoughts that I figured may be helpful.

Sincerely, Rick. "The Rock Man".
 
Can you shock the iron sands (heat them up in an oven then drop them into cold water) to split them to get at internal gold, or does that only work with quartz?
 
Drewbie said:
Can you shock the iron sands (heat them up in an oven then drop them into cold water) to split them to get at internal gold, or does that only work with quartz?

You should be able to roast them in salt and then drop them in water to fracture them.
 
Right. I just found the site where I read about it a while back (and promptly forgot half the story)...

http://www.nuggethunters.org/blacksand.html
 
hi dear all
my name is Hussin Naiji from Iran.
these posts are Interesting to me because i fined Soil samples containing micron gold .These samples are derived from river alluvium that Piled in the back of an old earth dam(of course The dam is ruined now and With over 600 years old).The soil samples were sent to the laboratory and Was answered by 50 ppm .
But the problem is that micron gold extraction techniques is not in Iran.
I need help for micron gold extraction techniques with Minimum investment .
Thousands of tons of soil is.
my email is [email protected]
'm waiting for comments.
sorry my English is bad i have transleted by google translater.
best regards
Hussin naiji
 
hussin,

I am not sure if you have much skill in mining, but what I would use is what nature used.

The reason the gold was at that dam was because of the nature of the gold, all of the other materials rocks sand and gravel were lighter than that gold, the gold settled at the dam because it was heavier or denser than the other materials, the dam acted as a sluice box riffle trapped and concentrated the gold in that spot of the river.

So that is how I would get that gold separated, by using golds density, material size separation screening, panning, sluicing, shaker tables, blue bowls, dredges, and other equipment, most of this mining equipment can be home made.

How you proceed would some what depend on how much material you are planing to do a day, a yard or a few tons.

I deleted your other post on this subject (double post), do not double post, your question will be read and answered by members, no need to fill the forum server up with your question.
 
The answer of 50 ppm does tell you what must be done to extract the gold, only that it is present.
Normally micron gold requires treatment with cyanide to dissolve.
 
Reno Chris said:
The answer of 50 ppm does tell you what must be done to extract the gold, only that it is present.
Normally micron gold requires treatment with cyanide to dissolve.
hi Reno Chris thanks for your post and time.
sorry I would amend 70 ppm. But in what form? Can I do it manually? For example, a bucket. The amount of cyanide for a bucket? The amount of activated carbon in a bucket?
I'd need more details. there is the link with more details ?
thanks again
Hussin
 
I would try gravity based techniques like the use of a gold pan to see if the material has gold which can be recovered that way. Google panning for gold to get more information.
Giving you information on using cyanide to recover gold is not simple. Cyanide is a deadly poison and there are entire books on the topic of how to use cyanide to recover gold. It is not something a beginner should attempt.
 
Reno Chris said:
The answer of 50 ppm does tell you what must be done to extract the gold, only that it is present.
Normally micron gold requires treatment with cyanide to dissolve.

All of that Iron affect the Cyanide extraction, I'm sure, especially if it's finely divided.
 
Reno Chris said:
I would try gravity based techniques like the use of a gold pan to see if the material has gold which can be recovered that way. Google panning for gold to get more information.
Giving you information on using cyanide to recover gold is not simple. Cyanide is a deadly poison and there are entire books on the topic of how to use cyanide to recover gold. It is not something a beginner should attempt.
Your advice is valuable for me.
thanks my dear Brother.
Hussin Naiji
 
HPIM2122.JPGI am also interested in recovering precious metals from black sands. I have run aqua regia through much of my material. I do use a small amount of nitric acid in the field on select rocks containing white looking metal. If the nitric acid does nothing to the white looking metal I take that rock home for crushing.

When dealing with magnetic material I can suggest heat quenching it. Get a metal coffee can punch some holes in the bottom , put about 2 inches of cheap char coal in the bottom. I start the coal with a MAP torch. Then in a cast iron tube with a cast iron bottom filled with magnetic material place in the center of the can. now fill the rest of the can with coal. I let mine cook for about 3 hours on the first run and two hours after that because the coal is not hot to begin with. Caution , this stuff gets real hot. Use tongs and welding gloves to keep from getting burned. Quickly pour the material into a 5 gallon bucket about 3/4 full of water. This will fracture the material. after cooling remove the magnetic material with a magnet. The material that is now not magnetic is what you want to clean up in other processes. I have had some small success with gold. I think I have found palladium and rhodium via flatbed XRF scan from a company in Florida , but they can not do business with miners. I am still looking for a reputable company that can do business with miners. After I clean up my now non magnetic material with hydrochloric acid until i can not get any color change. Then I use nitric acid to remove anything else. Now everything left goes in aqua regia at room temp. What I have left looks like this. The weather where I am is to cold to attempt to cook aqua regia to 130 degrees C for now.

Can anyone think of a mistake I may have done? Does anyone know an honest smelter slant buyer?

I have 3 different assays from 3 different companies. #1 says palladium and rhodium, but they do not do business with miners. #2 says titanium oxide with iron, they will not return my sample. #3 says nickel with chromium and selenium. All three three samples are from the same batch.
 
eng166 said:
Can anyone think of a mistake I may have done?
Did you get an assay? It would tell you what you have in your material. Is there a chance there is any arsenic in it? I would want to know that before I started throwing any of it in a fire. One of our members had an experience with arsenic. Perhaps Irons will let you know what that was like.

Dave
 
Its hard to convince folks of this, but there is nothing mysterious or magical about "Black Sands" most examples - like 99% - have only tiny traces of gold. Get assays done by a competent, qualified lab. Get a fire assay done or have the test done by AA. If the test shows just a trace or below detection - that's what you have. Almost nothing.
Most back sands that do have gold, have free gold that can be best recovered with gravity based methods. Meaning it is best processed with jigs, vibrating tables, blue bowls, spiral wheels and the like.

putting untested back sand into AR is worse than putting whole, fully populated computer boards directly in AR - both will make a big mess, but at least the computer board is likely to have more than just one or two PPM traces of gold.
 
Hussin, Dam sediments are usually fine grained sand to silt size particles. The richest gold concentrations should be where the flow of the river or creek first encounters the dam pond, when the current stops the gold should fall out quickly and seperate itself from the rest of the silt, which takes some time to settle out (muddy water takes all day to clear). You should see if it can be panned out gently in a gold pan, if so, then you should be able to sluice the material through a "beach box" which is a wide sluice with a thin veneer of water designed to extract gold from beach sand, tropical soils also typically carry very fine grained gold and they use a similar setup with two layers of burlap over a carpet, the gold falls through the burlap and sticks to the carpet. If the gold is too fine grained to catch using traditional equipment there are other ways that will work. Before you go and dump cyanide all over everything, you should check out "Mineral jigs" on the internet, you could buy a used one and retrofit it for your unique sedimentary environment (smaller holes and shot). More modern machines such as Knelson concentrators (the company has a catalog on the internet) can catch very fine grained gold and are made for applications like you describe, another comapany to check out is Icon a Canadian company that also specializes in fine grained gold recovery (Iconcentrator.com). Please by all means check out these techniques for recovering fine grained gold before using cyanide, low concentration cyanide heap leaching is for hard rock clasts on the order of 1 to 1/2 inch diameter, to wash your material would require large vats using a higher concentration of cyanide and several washes, you would have waste water to deal with, I would only use cyanide if I had alot of final concentrates under lab conditions,and AR would probably work just as well for small quantities of concentrate. Good luck
 
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