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#1 jake272727

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Posted 24 March 2010 - 01:28 PM

Why do more people not use a kiln on there black sands to get more gold out? Ive been looking at diff ways to make sure we get the most out of our black sand and this looks like the safest and easiest way after we use our shaker table.

#2 wolf

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Posted 24 March 2010 - 03:15 PM

Why do more people not use a kiln on there black sands to get more gold out? Ive been looking at diff ways to make sure we get the most out of our black sand and this looks like the safest and easiest way after we use our shaker table.


Thats kind of open ended jake.
How much black sand are you geting a day? what does it assay out to?
Are you in a placer or running a hardrock mill?
Is you gold visible under a ten power magnifying glass?
How do you plan on recovering your gold after you roast it?
Have you looked at other options for recovery?

I never heard of roasting black sands and i don't know why you would be using a table.

#3 nvchris

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Posted 24 March 2010 - 04:05 PM

The one good reason is........... A kiln (roasting) is expensive to operate ...... and thats only one small step in the process circuit.

find a smelter to handle it ......thats if it's got value.


an example of a process circuit,

0000950123-06-008409_Y22663Y2266301.gif

#4 jake272727

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Posted 24 March 2010 - 07:11 PM

Thats kind of open ended jake.
How much black sand are you geting a day? what does it assay out to?
Are you in a placer or running a hardrock mill?
Is you gold visible under a ten power magnifying glass?
How do you plan on recovering your gold after you roast it?
Have you looked at other options for recovery?

I never heard of roasting black sands and i don't know why you would be using a table.


Well we are getting about 4 to 6 5gal buckets a day of black sand from our placer operation and im not sure what it assays out to because i havnt bothered with any of my black sands yet. Ive checked into doing kilns on a number of web sites and it doensnt really look all that hard plus i have talked to a few people at prospecting shops that sell kilns and they say they work really well for what im planning on using them for. I use a shaker table to get most the gold but id like to free up alot of the gold that ive seen in the black sands.

#5 jake272727

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Posted 24 March 2010 - 07:13 PM

The one good reason is........... A kiln (roasting) is expensive to operate ...... and thats only one small step in the process circuit.

find a smelter to handle it ......thats if it's got value.


an example of a process circuit,

0000950123-06-008409_Y22663Y2266301.gif


Have you operated one? as far as ive seen it really isnt expensive compared to the gold recovery i should be getting out of it. I have not done this so i cant say its really cheap or really expensive but if you get more gold out of it than what it cost then id say its worth it.

#6 Uncle Ron

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Posted 24 March 2010 - 10:28 PM

Yo Jazz... I used to operate our mining company lab for final recovery and smelting....The amount of black sand you're talking about should be run through an amalgam based processor ...(Basically a small ball mill or similar with merc)... Then process the amalgam (carefully) and finally cook it off and smelt it down using a bone cupel to remove most impurities ... The details of this process are readily available online and in mining textbooks ... You wouldn't want to smelt the black sand directly... It would be expensive and probably not recover the gold efficiently... Good luck...Cheers, Unc

#7 wyldkatt

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Posted 25 March 2010 - 10:38 AM

Hello jake272727-
I believe what you are trying to do with the black sands,
is along the same lines as getting the gold out of locked up sulfides.

This fellow will give you an interesting take. http://www.freepaten.../EP0435479.html
I'm sure there are a few nuggets in there to extract.
Good luck, and maybe some pics of your process would be cool!
There's plenty more info out there about the sulfides thing tho.

~wyld~

#8 russfordAZ

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Posted 25 March 2010 - 11:30 AM

I agree with Wyld. Here are some things to consider:

There are basically two forms of gold in black sands. 1. "Free gold" and 2. Sulfide gold. Here's the difference.

Free gold is just that...free. It looks like gold and is usually not attached to other minerals. You can almost always tell if you have free gold in your sands no matter how small the specks by just looking through a magnifying glass or microscope. They will look like little gold nuggets even at 500 power. There are many ways to recover free gold by mechanical methods such as pans, sluices, spiral wheels, jigs, etc.. Another way to collect free gold is chemical, such as mercury, leaching, Aqua Regia, etc. Most guys worry about the gold they "think" is in their sands before they even test to see if they have any. Even after not seeing any free gold, they still believe it's there and they must be missing it.... that's where sulfide gold comes in.

Sulfide Gold:
To start with, let me say that from an economic standpoint, Sulfide gold is usually not worth going after; it's usually a case of diminishing returns. It is labor intensive and not cost effective in most cases, especially if you have a large quantity of low quality sands to deal with. However, black sands from some areas do contain paying quantities of sulfide gold so, it is a good idea to concentrate your black sands and test them to see how much, if any, sulfide gold you have. If you look at your cons wet in your pan with a good glass, the sulfides will show the bright shinny colors..blue, green, reds, and yellows. The best method of recovery for sulfide gold is heat, but a fuel source can be expensive. The old timers used to "roast" their cons over the camp fire to burn off the sulfides (they put out a sulfur, or rotten egg smell). They could then re-pan the cons to recover the sulfide gold. One method of doing this is to cut the top out of a 55 gallon barrel and hammer it into a slight dish. Spread your sands out fairly thinly over it and place it over the fire. Take it off when the rotten egg smell is no longer in the air. Sulfide gold has a different elemental makeup before it's heated and does not look like gold under magnification...that's why you should test to see if it's there and to what extent. Having said this, most black sand will not contain sulfide gold in paying amounts. Leaching, fire assay, and AR will recover any sulfide gold present, but mercury will not unless the sands are roasted first.

It sounds to me from reading this thread- what you are asking is about recovery of sulfide gold. Roasting to recover the sulfides and smelting, leaching, or acids to recover all available gold are two completely different things. There is a whole library of info out there on these subjects and it takes years of study to become knowledgeable. When dealing with this subject (whether sulfides or free gold in plain black sands) you will eventually come to that "point of diminishing returns". Most black sands don't contain enough Sulfide gold to pay for the electricity to use a furnace much less the cost of setting up a lab or buying the chemicals and of course these processes are very time consuming. Most small miners are better off to send a small amount of their cons out to be tested. In any event it is unnecessary to save all of your sands. Just run your cons through a spiral wheel and save the heaviest of your cons. Hope this helps. ...rf

#9 jake272727

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Posted 25 March 2010 - 03:28 PM

Hello jake272727-
I believe what you are trying to do with the black sands,
is along the same lines as getting the gold out of locked up sulfides.

This fellow will give you an interesting take. http://www.freepaten.../EP0435479.html
I'm sure there are a few nuggets in there to extract.
Good luck, and maybe some pics of your process would be cool!
There's plenty more info out there about the sulfides thing tho.

~wyld~

here is a link to our wash plant

#10 jake272727

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Posted 25 March 2010 - 03:35 PM

I agree with Wyld. Here are some things to consider:

There are basically two forms of gold in black sands. 1. "Free gold" and 2. Sulfide gold. Here's the difference.

Free gold is just that...free. It looks like gold and is usually not attached to other minerals. You can almost always tell if you have free gold in your sands no matter how small the specks by just looking through a magnifying glass or microscope. They will look like little gold nuggets even at 500 power. There are many ways to recover free gold by mechanical methods such as pans, sluices, spiral wheels, jigs, etc.. Another way to collect free gold is chemical, such as mercury, leaching, Aqua Regia, etc. Most guys worry about the gold they "think" is in their sands before they even test to see if they have any. Even after not seeing any free gold, they still believe it's there and they must be missing it.... that's where sulfide gold comes in.

Sulfide Gold:
To start with, let me say that from an economic standpoint, Sulfide gold is usually not worth going after; it's usually a case of diminishing returns. It is labor intensive and not cost effective in most cases, especially if you have a large quantity of low quality sands to deal with. However, black sands from some areas do contain paying quantities of sulfide gold so, it is a good idea to concentrate your black sands and test them to see how much, if any, sulfide gold you have. If you look at your cons wet in your pan with a good glass, the sulfides will show the bright shinny colors..blue, green, reds, and yellows. The best method of recovery for sulfide gold is heat, but a fuel source can be expensive. The old timers used to "roast" their cons over the camp fire to burn off the sulfides (they put out a sulfur, or rotten egg smell). They could then re-pan the cons to recover the sulfide gold. One method of doing this is to cut the top out of a 55 gallon barrel and hammer it into a slight dish. Spread your sands out fairly thinly over it and place it over the fire. Take it off when the rotten egg smell is no longer in the air. Sulfide gold has a different elemental makeup before it's heated and does not look like gold under magnification...that's why you should test to see if it's there and to what extent. Having said this, most black sand will not contain sulfide gold in paying amounts. Leaching, fire assay, and AR will recover any sulfide gold present, but mercury will not unless the sands are roasted first.

It sounds to me from reading this thread- what you are asking is about recovery of sulfide gold. Roasting to recover the sulfides and smelting, leaching, or acids to recover all available gold are two completely different things. There is a whole library of info out there on these subjects and it takes years of study to become knowledgeable. When dealing with this subject (whether sulfides or free gold in plain black sands) you will eventually come to that "point of diminishing returns". Most black sands don't contain enough Sulfide gold to pay for the electricity to use a furnace much less the cost of setting up a lab or buying the chemicals and of course these processes are very time consuming. Most small miners are better off to send a small amount of their cons out to be tested. In any event it is unnecessary to save all of your sands. Just run your cons through a spiral wheel and save the heaviest of your cons. Hope this helps. ...rf

Thanks for all the info. I was looking at just getting a kiln that ran off of propane from A and B prospecting and trying to see what was in it. I also ran accross this website but damn there is so much info on everything its hard to sift between fact and fiction without just trying it myself. http://www.nuggethun...g/smelting.html maybe see if you check that out and see if it looks good. Thanks again all input is appreciated.

#11 russfordAZ

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Posted 26 March 2010 - 09:12 AM

Jake,
if you want to get into this, I say go for it. However, please be aware that it is a big commitment and there will be many expenses involved that you may not be aware of at this time (not to mention the days-weeks-months of reading/self-education). As I said, for most small miners, they will be way ahead of the game (dollar wise) to just send their cons (super cons) to a lab. I can perform that service for anyone who is interested. Nuggethunters.org is a good site. However there are many other ways to do this and determining which process is best would best be left to someone with experience. The point I was trying to make is this:

Minimum cost to do one test (to set up a lab multiply X 4 !)
Furnace (gas or electric).... 400 - 1000
Crucible ....................... 10-15
Flux .............................. 3-5
Electricity ( or gas).......... 5
Safety equipment............... 50 and
fire extinguisher ............. 100
cone mold ....................... 50
mortar and pestle ............ 20 /or
tumbler ..................... 100
tongs/glassware .............. 50
the list goes on and on.

One statement they make on that site that I disagree with is this:
"..It's a known fact that there can be 4 - 10 times more Gold in your concentrates than the visible Gold that you can see and recover..."
I have never found even the same amount of sulfide gold as free gold in my samples. I'm not saying it couldn't happen, I'm just saying, in AZ I've never found that to be true, and I think it is a misleading statement for the most part. Good luck with your project. :)

...rf

#12 ALASKA JOE

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Posted 30 March 2010 - 07:52 PM

The GGPA (Georgia Gold Prospectors' Association) site has been a source of well intentioned, melting, folly for years.

The "club", itself, imploded around a central core of ambitious, self centered, "management". The upshot is that club members were slowly and meticulously pressured out of the group while potential new members were (and are) denied acceptance. "Management", and some of their lackies, now mine the Associations' land unfettered by other members of consequence.

If you do wish, based on that single encouragement to just melt down your Magnetite, Hematite and Gold - be prepared for substancial, unexpected problems. You would be well advised to learn all you can about what you're considering doing before you wade into unfamiliar waters. Been there, done that, sir.

There is a Refiners' Forum website and they are The prime source for high tech refining info. They are all top shelf in knowledge on any chemical or related refining of various metals - including recovering Platinum and other valuable metals from scrap sources.

If you feel compelled to recovering metals (like Gold or Silver)from Sulphites consider going to the "Caveman Chemistry" website. Open air roasting a finely powdered sulphide ore will generate Sulphur DiOxide in breaking down the sulfur bonds and then a second roasting, in a closed container in the presence of Carbon, will result in the free metal being produced.

Bottom line - unless you can economically justify the secondary refining process for Sulphides either sell or consign them to a specialist or, if there is not enough volume of the specialized concentrates, don't bother with the expense, time and effort in dealing with them yourself.

Joe

#13 russfordAZ

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Posted 31 March 2010 - 05:02 PM

here is a link to our wash plant

Jake,
That's a great little wash plant. Goldfield makes top-of-the-line equipment. Years ago I had their "Goldtron" black sand table and it was super. I noticed that the rocks are stacking up pretty close to your sluice. Is there a way to add an extension on to get them farther away? If you feed that plant steady, you may need a bigger sluice and a bigger water supply. Did you have any trouble getting a permit for that loader and backhoe? It all looks like a pretty slick operation. How's it working out? ...russ

#14 bigrex

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Posted 01 April 2010 - 01:03 AM

Here's a video I like on processing concentrates, you may already do something similar to maximize your take:

http://prospectingch...oncentrate.html

I guess it's really only the last ten minutes of the video where he does his 100 mesh minus cleanup

#15 jake272727

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Posted 01 April 2010 - 11:20 AM

Jake,
That's a great little wash plant. Goldfield makes top-of-the-line equipment. Years ago I had their "Goldtron" black sand table and it was super. I noticed that the rocks are stacking up pretty close to your sluice. Is there a way to add an extension on to get them farther away? If you feed that plant steady, you may need a bigger sluice and a bigger water supply. Did you have any trouble getting a permit for that loader and backhoe? It all looks like a pretty slick operation. How's it working out? ...russ


Russ this was just kind of a practice run to get us familiar to what we need to do and the washplant is a protype that we had goldfield build. We actually bought an extra 15 ft of keene sluice that we now run with it. We are looking into maybe getting a small conveyor for the rocks comming off and we are also looking at getting a screening plant with a conveyor to feed our plant. At this time we are shut down for the summer doing our main jobs but im hoping to get back down there this winter and spend a good winter on our claim. I have all the black sands from what we ran for about a month and most of our gold was really fine so thats why i thought i could check into doing some melting.

#16 jake272727

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Posted 01 April 2010 - 12:05 PM

Here's a video I like on processing concentrates, you may already do something similar to maximize your take:

http://prospectingch...oncentrate.html

I guess it's really only the last ten minutes of the video where he does his 100 mesh minus cleanup


that was a good video but i dont have a blue bowl we have a shaker table so im not sure which is better to use. We run our shaker table but i still end up with alot of fines that i couldnt pan out so maybe that might be something to look into besides running a kiln.

#17 Wyndham

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Posted 01 April 2010 - 01:58 PM

I'm a potter and have both gas and electric kilns. A simple gas fired kiln for roasting can be made at a minimum cost. I have not roasted blk sands but in other discussions others have mentioned the fact that some blk sands may contain arsenic in the sulphides and if this is done indoors or closed in area, watch out.
Electric kiln heat up slowly and I don't think would work well for your purpose.
Go over to Mesa community college and talk to some potters about the burners for a Raku kiln and then use the idea posted above for roasting over a fire but using propane instead of camp fire. You might consider a harrow disk from a plow and weld up the hole on the middle, it would be like a big Wok.....second thought there are some outdoor propane burners used for Turkey deep fat frying and that burner head might work better.
Be careful there's more ways to get it wrong than right. Wyndham

#18 russfordAZ

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Posted 02 April 2010 - 09:45 AM

Jake, the blue bowl is only designed to recover very fine gold and it is very, very slow to operate. So, if you have a large quantity of black sands, you'd have to concentrate them down first by running the sands thru a mini sluice, spiral wheel, table etc, and then screen them down to at least -30 or -40mesh. That will reduce the quantity of your cons down to something you could work with, but it will still take hours and hours to recover your fine gold. For cons over -30 mesh in size, I believe the fastest method is still a good spiral wheel (provided it is set up and operated correctly). You don't have to process all of your cons for sulfide gold until you test them first and make the decision that there is enough gold there to mess with. Another point to think about is that you will probably lose most of your micron gold in these processes if you use any recovery process with moving water. Micron gold is gold so small that it is suspended in the water. Smelting, Aqua Regia, Fire assay etc will get all of the gold present, but is only suitable for testing small quantities because of the time and costs involved. No one is ever able to recovery "all" of the gold present in their sands. At some point you have to say, "I gave it my best shot, and my time is worth more than the gold I am now getting". I would recommend an assay before you start the recovery on your super cons and another one when you think you've gotten as much of the gold as you can. Most assays run $35-$50.
:) Good luck....rf



I use the Action Mining M4 Mill Wave table (lab model). It will do a fairly decent job on black sands, but is not that fast and still loses a small percent of the micron gold.


Another method that you may want to consider is amalgamation, if all you have is fine gold. It is a multi-step process when done right. After you concentrate your sands down to super-cons, you have to clean any film coating off the gold so that it will stick to the mercury. This involves tumbling with certain cleaners, rinsing, and then tumbling with merc. The process is labor intensive, but will do a fairly decent job on most fine gold. This process is not as technical or as expensive as some other, so it may be used by anyone with the time and interest. Please read up on the dangers of mercury before you use it... it can kill you.

#19 Goldeagle

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Posted 02 April 2010 - 07:58 PM

Why do more people not use a kiln on there black sands to get more gold out? Ive been looking at diff ways to make sure we get the most out of our black sand and this looks like the safest and easiest way after we use our shaker table.

Jake How is this claim working out , are you getting enough gold to meet costs , . Don

#20 bigrex

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Posted 05 April 2010 - 01:50 AM

that was a good video but i dont have a blue bowl we have a shaker table so im not sure which is better to use. We run our shaker table but i still end up with alot of fines that i couldnt pan out so maybe that might be something to look into besides running a kiln.


I agree with Russ that the blue bowl would be better for smaller quantities of black sand. I figured once you screened everything down to 100 mesh, there would not be much of that to run through the blue bowl (comparatively speaking), but it would probably take forever to classify it all down I would think. Anyway, I'm just talking theory since I have no direct experience with large quantities of fines, Russ has more practical advise for you. Good luck, great looking operation by the way, it reminds me a little of the ruby mine set-up we had in NC several years ago.

#21 Goldeagle

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Posted 05 April 2010 - 05:42 PM

Jake,
That's a great little wash plant. Goldfield makes top-of-the-line equipment. Years ago I had their "Goldtron" black sand table and it was super. I noticed that the rocks are stacking up pretty close to your sluice. Is there a way to add an extension on to get them farther away? If you feed that plant steady, you may need a bigger sluice and a bigger water supply. Did you have any trouble getting a permit for that loader and backhoe? It all looks like a pretty slick operation. How's it working out? ...russ


Hi Jake WEb had several operations , one on the west side of the dome rocks and one on the Hassiampa . We used two lined tanks one for settling and one for our pump . We used a five cylinder Lister diesel pump . The first tank helped in settling out the silt , so less in our wash water . Just a thought that might help your fine gold recovery.
Don




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