# Refining Gold Ore Help



## RobertPress (May 31, 2011)

Hello My friend and I found some gold ore, crushed up 26 pounds of it and ran it through the stages dissolving it into solution then precipitated it and everything seemed to be going very well. After we strained out the precipitant is when we started having problems and we were wondering if anyone could shed some light on our errors. We took the gold dust and to speed up the drying time tried to use acetone which we are not sure if it was a problem or not however when we tried to melt our first brick we got the metal to burn the perfect color mixed with borax flux in the crucible. However when we took out the metal from the graphite tray it seemed to have white spots which I assume is us using to much borax. "if anyone can give an exact break down of how much should be used would be great" As well as what once looked like liquid gold turned into a black brick "oxidization?" with gold flakes shinning through, that was also quite brittle, any suggestions? As well as what is the best way of actually straining the gold dust we used pretty much a cheese cloth to strain it from the percipitant solution. Please any suggestions?


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## eeTHr (May 31, 2011)

There are two very different categories of processing gold and other PMs (Precious Metals).

One is recovery.

The other is refining.

Recovery generally has the end result of separating all PMs from the base metals and other materials.

Refining is separating the PMs from each other, and obtaining some degree of purity, usually 99.9% or better.

What you attempted is only recovery. Methods of recovery from ore vary widely, depending on the entire contents of the ore. Various materials in different ores can make recovery difficult, and sometimes require different methods altogether. Others in this forum know much more about this than I do, and will possibly help you, if you take their advice.

My point is that you shouldn't expect to get refined gold from recovery methods. You can get dore bars, of mixed metals, including some base metals, but it won't behave like refined gold. It appears that you are not up to the dore bar point on your recovery, yet.


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## Palladium (May 31, 2011)

eeTHr said:


> There are two very different categories of processing gold and other PMs (Precious Metals).
> 
> One is recovery.
> 
> ...


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## Harold_V (May 31, 2011)

RobertPress said:


> with gold flakes shinning through, that was also quite brittle, any suggestions? As well as what is the best way of actually straining the gold dust we used pretty much a cheese cloth to strain it from the percipitant solution. Please any suggestions?


You're not going to like my suggestion. 

Lose the notion you have gold. 

My money says you have been processing a sulfide. It may have traces of gold within, buy you're not going to make a recovery by the methods you're using. 

Did you get an assay on your material? 

If not, why not?

Assuming you have gold when you are not well versed in the materials you encounter is not a wise thing to do. Do not allow gold fever to control your logic. 

Harold


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## CornFed (Jul 24, 2011)

Harold_V said:


> RobertPress said:
> 
> 
> > with gold flakes shinning through, that was also quite brittle, any suggestions? As well as what is the best way of actually straining the gold dust we used pretty much a cheese cloth to strain it from the percipitant solution. Please any suggestions?
> ...


 It seems you advise many to acquire an assay. I think it is met by most with skepticism because it goes against the idea of independence that gold, gold recovery and refinement symbolizes to many new and old. And it buys into big brother a bit. Because its hard for the independent mind to accept what it does not fully understand. If gold were available to all every where what would happen? The logical mind can not omit that our economy is based on trial and error which has with it fear and greed. Thus what people say is often not what they mean but rather an essence of there uncertainty and fear of loss of investment and control.


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## eeTHr (Jul 24, 2011)

It would help if you say what you used in the dissolving step. If you used acids, like Aqua Regia (AR), or Muriatic with Clorox (HCl/Cl), and then you precipitated with Sodium Metabisulfite (SMB) or Ferrous Sulfate (Copperas), you would have missed any PGMs and thrown them out with the spent solution.

If you dissolved with acids, your best bet for a recovery precipitant method would be the cementation method, with a copper bar or thick solid wire like size AWG 0-0, suspended in the solution.

You should let all your remaining sediments settle to the bottom after the dissolving step, and decant the pregnant solution by either pouring off or siphoning, to another container, through a funnel with a filter, leaving all the sediment in the bottom of the original container. To rinse any remaining solution from the sediment, add just enough water to cover it, plus a little more, then decant again the same way. You can rinse it like this as many times as you feel is necessary (usually three).

Then precipitate the values with the solid copper. Copper will bring down _*all*_ precious metals (PMs). To produce a dore bar from these powders, pre-coat the curcible with just enough borax to make it shiny all over the inside, then add your powder and melt.

Or, instead of making a dore bar, refine the powders using methods found on this site.

On the other hand, if you used a base solution to dissolve, you will need to get help from someone on here who is familiar with those methods.

If you don't want to get an assay, your first step should be to dissolve a small sample of your ore, make sure there is no nitric or chlorine left in it, and test it with stannous chloride using the methods described on this site. This test will reveal if the solution contains gold, platimun, or palladium.

Use rubber gloves, long sleeves, buttoned up shirt, and full face shield. A fume hood is highly recommended for refining, or else do it all outdoors, with any wind, plus a strong fan, behind you.

This is a rough outline of methods. You can use this information to search for greater detail on each step, if necessary.


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## nickvc (Jul 24, 2011)

Cornfed the reason Harold advises members to get assays is that it will long term save money and time it's pointless working your tail off for no good purpose for days or weeks or months on worthless or even dangerous materials that could damage your health and your wallet.
While we seem to have many who join the forum who think they have found gold it appears they don't stay long once the introduction of science is added to their dreams, workable, safe and worth while ores aren't that common and even when found no two are rarely the same and finding ways to extract the gold is the same rarely easy but we all on the forum hope, along with the miners and prospectors, that they have indeed found gold.


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## Palladium (Jul 24, 2011)

Another thing people fail to realize with ore is that an assay only tells you how much of something is there. Getting that amount out and figuring out how to do it is a whole nother process in and of it's self.


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## jimdoc (Jul 24, 2011)

Palladium said:


> Another thing people fail to realize with ore is that an assay only tells you how much of something is there. Getting that amount out and figuring out how to do it is a whole nother process in and of it's self.




Remember this Barrick problem?;

http://www.barrick.com/News/PressReleases/PressReleaseDetails/2007/BarrickGoldExtendsDeadlinetoApril30for10MillionUnlocktheValueProgram/default.aspx

Jim


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## Palladium (Jul 24, 2011)

http://www.unlockthevalue.com/SilverRecovery.aspx


You would think somebody would have listened. Rotfl


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## Harold_V (Jul 25, 2011)

CornFed said:


> It seems you advise many to acquire an assay. I think it is met by most with skepticism because it goes against the idea of independence that gold, gold recovery and refinement symbolizes to many new and old. And it buys into big brother a bit. Because its hard for the independent mind to accept what it does not fully understand. If gold were available to all every where what would happen? The logical mind can not omit that our economy is based on trial and error which has with it fear and greed. Thus what people say is often not what they mean but rather an essence of there uncertainty and fear of loss of investment and control.


Heh! Can't speak for you, but I'm not inclined to chase my tail. What an assay accomplishes for an individual is give him/her direction. Should they, or should they not, pursue a venture? 

We, here, are men of science. None of this is a mystery, and none of it should be trusted to luck. Anyone that is willing to participate in a blind venture deserves exactly what they're likely to reap, and it isn't always good. 

I'm going to relate a real life experience I had. I had been refining for about six years when a neighbor approached me. I had not made his acquaintance, as he lived a couple blocks away, on a street I never travelled. This neighbor related to me that he, his father-in-law, and a friend, had spent three months working a claim in Nevada. The spoils were recovered in the way of black sands and free gold, albeit small in nature. He told me that he had spent a couple weeks trying to recover the values, and feared he had lost most of them. To add to his misery, his father-in-law had a heart attack while they were working the claim, and died because they were a long ways from help. 

My first question to him was "what did the head assay show?"

"Huh?", was his response. 

"The head assay. You know, the assay you had performed that helped you make a decision to pursue this venture."

"Oh", he tells me. "We didn't get an assay". 

"Why then, did you decide to spend three months of your life attempting to recover an unknown?" I asked of him. 

He replied "well, you could see the gold. We figured there was plenty there, enough to warrant our efforts".

Do keep in mind, this was intended to be a business venture---not a "panning trip for pleasure". 

Have you ever explored gold that is commonly found in black sand? It's generally only a couple ten thousandths of an inch thick, and typically very small in diameter. It weighs nearly nothing. 

I don't recall the amount of money they spent, but for all their trouble, they recovered about 5½ ounces of gold, and paid the price of one person losing their life. Not bad for three guys working an entire summer, with one losing his life, eh?

Tell me, do you think an assay is a good idea? If not, why not? 

The notion that "big brother" is involved with this is all in your mind. An independent assayer has no reason in the world to involve the government in his results, nor are you, or anyone, bound to disclose the location of the ore you wish to have assayed. Please stop reading so damned many fiction books and get on with real life. You sound as if you think the entire world is conspiring against you. 

An assay is to a prospector what eye sight is to a driver of an automobile. it alerts you to what is----and, hopefully----keeps your head out of that eternal dark spot. 

Harold


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## Reno Chris (Jul 25, 2011)

*My money says you have been processing a sulfide.*

Reading this I came up with the exactly the same answer. Tarnishing "metal" and brittle "gold" material in the ore. Both point to sulfides. Most sulfides, including pyrite, will melt nicely at a reasonable red heat. Melted sulfides are known as "Matte". If you had a high sulfide ore, crushed it and added some borax flux and heated it to a nice read heat, silica and other oxides will mix with the borax, and the sulfides (er, I mean gold) should melt and collect at the bottom of the crucible. You pour off the flux, and Voila! You pour a heavy brick of sulfide and think its gold. No assays needed - because we know its rich. :lol: 

Of course it starts to tarnish right away and is almost as brittle as glass, but is that a problem? Doesn't that happen to most gold? :lol: 

Isn't everything that's colored metallic yellow actually made of gold? :lol: 

I knew a guy in Nevada with a very similar story to Harold's. A guy sold his house and bought a used bulldozer, front end loader and placer trommel plant. I asked him if he had sampled and he told me he didn't need to - because he knew it was rich. He and his two teenage sons worked for 3 months and recovered about 3 ounces - not even enough to pay for the diesel to run the equipment. The sons got to learn their father was a moron. So that's long been one of my favorite sayings - "*We dont need to sample because we know its rich.*"


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## goldsilverpro (Jul 25, 2011)

Please pardon my rant.

In my experience, if the assays show little or no gold, they often won't be believed. While spending 2 years of my life doing reliable honest assays for miners, that's what turned me off the most. In a majority of times, if the results were low, they wouldn't believe them and I usually got no more business from them. Most miners, it seems, want to believe they have found the mother lode and, since they have already spent a lot of time and money on their material, they have a very hard time listening to reason. Some miners keep sending samples to different assayers until they find one that gives them the results they want, erroneous or not. I came to believe that some of the most successful assayers are those that report phony high results (and, believe me, these guys do exist). I stopped doing assays for miners over 25 years ago and will never do it again. If, back then, I had met more people like Reno Chris, I would undoubtedly have a different attitude. LISTEN TO HIM!


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## dorki22 (Jul 25, 2011)

Reno Chris said:


> *My money says you have been processing a sulfide.*
> 
> Reading this I came up with the exactly the same answer. Tarnishing "metal" and brittle "gold" material in the ore. Both point to sulfides. Most sulfides, including pyrite, will melt nicely at a reasonable red heat. Melted sulfides are known as "Matte". If you had a high sulfide ore, crushed it and added some borax flux and heated it to a nice read heat, silica and other oxides will mix with the borax, and the sulfides (er, I mean gold) should melt and collect at the bottom of the crucible. You pour off the flux, and Voila! You pour a heavy brick of sulfide and think its gold. No assays needed - because we know its rich. :lol:
> 
> ...



Hi, Chris.

I dont know if this is a simple question, but anyway:

How can you tell what is a sulfide, when you look at a sample ore? Are there obvious signs, experience maybe, testing? 

Simon


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## Palladium (Jul 25, 2011)

goldsilverpro said:


> If, back then, I had met more people like Reno Chris, I would undoubtedly have a different attitude. LISTEN TO HIM!



I have come to enjoy Chris's replies and the information he posts on the forum. I have found him to be very informative and an asset to the forum. Thanks for your contributions Chris. 

Both Chris's. 8) 8) 8)


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## Harold_V (Jul 25, 2011)

goldsilverpro said:


> Please pardon my rant.
> 
> In my experience, if the assays show little or no gold, they often won't be believed. While spending 2 years of my life doing reliable honest assays for miners, that's what turned me off the most. In a majority of times, if the results were low, they wouldn't believe them and I usually got no more business from them. Most miners, it seems, want to believe they have found the mother lode and, since they have already spent a lot of time and money on their material, they have a very hard time listening to reason. Some miners keep sending samples to different assayers until they find one that gives them the results they want, erroneous or not. I came to believe that some of the most successful assayers are those that report phony high results (and, believe me, these guys do exist). I stopped doing assays for miners over 25 years ago and will never do it again. If, back then, I had met more people like Reno Chris, I would undoubtedly have a different attitude. LISTEN TO HIM!


I have commented, in the past, that the worst people I ever encountered were prospectors. They tend to be the least educated, and have unreasonable expectations. As you alluded, they seek what they want to hear, not what is true, and tend to be willing to fight to the death if your comments don't support what they want to hear. 

One of the worst experiences I had was refining a small lot of placer that was particularly high in silver. For some strange reason, the owner submitted a given amount of weight, and expected that amount in return---although his objective was to refine the submitted gold. He couldn't grasp the idea that one refines to eliminate that which is not gold---that in the process weight is lost, because, in fact, it *isn't* gold, and is the reason the material, which is gold bearing, must be refined. 

There is no one so dangerous as a person that knows nothing, yet thinks he is well versed. That description was suited to the vast majority of those that fancied themselves as prospectors. Needless to say, they're not all morons, but there's on shortage of morons amongst them. 

Reno Chris is proving to be one of the most knowledgeable readers we've had introduced to our ranks. His experience and wisdom is exceptional. 

Harold


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## Harold_V (Jul 25, 2011)

dorki22 said:


> Hi, Chris.
> 
> I dont know if this is a simple question, but anyway:
> 
> ...


Simon,
If you'll pardon me for jumping in, in Chris' absence, sulfides have a common characteristic. They're brittle as glass. If you have a specimen you suspect is gold, crush a small portion. If it flattens, but stays together as a common mass, pretty good chance it's gold. If it's a sulfide, it will shatter to dust. No question that it isn't gold, although it may contain gold within, even at a microscopic level. Assays are the answer when you have a question. 

Chris---please don't allow my comments to relieve you of your answer. The more that can be said, the better we all learn. Looking forward to reading what you have to say on the subject. 

Harold


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## Reno Chris (Jul 25, 2011)

> *How can you tell what is a sulfide, when you look at a sample ore? Are there obvious signs, experience maybe, testing?*


For those who have seen a lot of gold and a lot of sulfides, its really not that hard to tell. 

For a new guy, perhaps the easiest test you can do is to place the material on a flat, smooth surface and hit it firmly with a hammer.

Mica (something many folks commonly mistake for gold) breaks down into a bunch of flat, glitter like flakes when struck. Pyrite (and other yellow sulfides) are brittle and will shatter into a bunch of little golden bits. Genuine gold will flatten out unbroken. If you have a small lead fishing weight - hit that with the hammer and it will show you how gold will behave because gold is malleable in a way similar to lead.


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## Reno Chris (Jul 25, 2011)

Goldsilverpro, Palladuim, Harold_V -

Thanks much, you guys are very kind. There are a lot of interesting topics on this forum. 

Chris


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## Harold_V (Jul 25, 2011)

I just had another thought. I have a few specimens of the ore I processed that assayed over 300 ounces/ton gold. In these samples, there's an abundance of iron pyrite, which, to the untrained eye, looks a great deal like gold. Fortunatly, right along side the pyrite is a band of gold. The color difference is astounding. Pyrite has a rather dull yellow color, leaning even a little gray, while gold has a rich yellow luster. Difficult to discern unless you have both of them present, however, unless you have an exceptional eye for colors.

Harold


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## Richard36 (Jul 25, 2011)

Palladium said:


> goldsilverpro said:
> 
> 
> > If, back then, I had met more people like Reno Chris, I would undoubtedly have a different attitude. LISTEN TO HIM!
> ...



I agree. 
I've sort of been holding back on my comments just so I could read what Chris has wrote.

You're pretty darn good Chris. 

Yes, smashing them with a knife blade, hammer, screwdriver, anything steel, will cause a sulfide to crumble and shatter.
Gold will smash, cut, and bend.

Sulfides will usually produce Hydrogen Sulfide gas (Rotten egg smell) if dissolved in Hydrochloric acid.
Gold will not.

Sulfides, and mica will easily move with water in a pan, gold will not. 
Small gold will act the same way as fine lead shavings within your pan.

That's why the more proficient panners use a small piece, or pieces of lead the size of the available gold as a safety. 
If you pan it down, and still have the lead, then you were panning correctly.

Just my thoughts on the subject.

Sincerely, Rick. "The Rock Man".


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## NoIdea (Jul 25, 2011)

Hi Harold - as i have never seen ore with gold in it gefore, is their any chance please for a couple of arrows on your pic, pointing out pyrite and gold.

Cheers

Deano


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## Harold_V (Jul 25, 2011)

NoIdea said:


> Hi Harold - as i have never seen ore with gold in it gefore, is their any chance please for a couple of arrows on your pic, pointing out pyrite and gold.
> 
> Cheers
> 
> Deano


Deano,
What I'll try to do is take a new picture of one of the best specimens, larger than that which was posted. That will provide much better detail, so it will help you see the difference. Give me at least a day---I'm spread thin. If the picture alone doesn't show the difference, I'll point out what is gold, and what is pyrite. 

The gold in these samples was found two ways. Heavy concentration that looked like gold, then there were areas that the gold was microscopic in nature, visible, really, only by magnification. I used a 400 power 'scope to help me understand the nature of the deposit, so I could formulate a plan for recovery. As is typical of gold that is finely divided, the areas of the ore that contained the fine gold actually have a rather gray appearance---although with light held just right, in particular on a face that has seen a rock saw, it's obvious it's gold. 

For now, the small piece, bottom left corner, the yellow you see in heavy concentration is gold. The sample is not in my hands, and I don't recall if there's any pyrite in that particular sample, but it abounds in some of them. 

I'll get back to you. 

Harold


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## Harold_V (Jul 26, 2011)

Ok, Deano! A slower than normal evening on the fora allowed me to try for an acceptable picture of the gold ore I mentioned. Sadly, the results are not what had hoped, in spite of having taken several. Seeing the examples in person leaves no doubt in one's mind what is seen, but a photograph (at least at my hand. I am not known for my skills as a photographer) tends to soften the differences. 

In the original picture, I showed four different samples, all from the original high grade ore I processed. The owner of the ore had given me the various samples, some of which were cut with a rock saw. They easily show what is, and what isn't, gold. The broken sections do as well, but it tends to get washed out in the picture. As a result, I have included a small nugget that has a rather large area of gold, so you can easily see the color differences. It is the center piece, at the bottom. The matrix is what I'd call quartz, although I am not a geologist and may not understand its true identity. Suffice it to say, it is a white rock that is slightly stained with iron (rust). 

The other two pieces are the ore in question. The one on the left shows a yellow material, all of which is gold, although very small in size. By contrast, the piece on the right, which is saw cut, displays pyrite, or fool's gold. There is ample gold in that sample as well, although it is not obvious, as it is very finely divided. It would be very obvious were you to see the sample in person. You can safely conclude that everything that is remotely yellow (yellow gray, really) in color is pyrite. 

Sorry the picture isn't of greater quality, but I hope it helps you see the difference between pyrite and gold.

To see the picture in a larger format, click on the picture. To see it even larger, click on the enlarged picture for an even larger display. The colors come through much better, which will help you understand the differences. 

Harold


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## NoIdea (Jul 26, 2011)

Thanks Harold, great pic.

Not as easy as it should look :lol: . 

20yrs ago while prospecting in Golden Bay, NZ, i found a piece of quartz with what a assumed was a small bit of gold, the quartz was about 4mm diameter. Lost it somewhere in my travels over the years. 

I loved the back breaking work, just to see that color sitting in the bottom of your ban at the end of the day. Did a wee bit (one day) of underwater dredging, mask, air compressor, full with water pump attached to a lawn mower motor, floating behind me along with the sluice box. Ahhh those wer the days  

Again Thanks

Deano


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## dorki22 (Jul 26, 2011)

Richard36 said:


> Palladium said:
> 
> 
> > goldsilverpro said:
> ...



Harold, Chris thank you both - you have been great help! I consider myself very lucky getting good advice from experienced guys like you all.
My problem is small size of potencial gold flakes.

Rick, same goes for you -thanks!- you have given me an idea :idea: 

If sulfides ready dissolve in Hydrochloric acid, then I reduced my options to mica or gold. I have some classified sand - mesh 30 - and a lot ( I mean a lot) of small golden dust not-greater than a few milimeters or less.

Its very hard to grab this litlle particles, but I ll try to get some -and test:

1. first mehanical - if it bends - cool
2. pouring some Hcl without bleach, and wait for reaction. If none, I'll add a drop of bleach and test with stannous. I wonder if yust a few little flakes will show positive, If gold - if this is the case I can skip the first test.

Man I totally forgot to test - oh, the fever can mix your head 

Its from an ancient river deposit of gravel - depth of 10 meters, just above the harden part, where gravel is compressed to hard rock - like konglomerat.
There is a commercial operation in progress, but they go just for gravel, so I just bought some sand :shock: 

The river is known for centuries for its gold, so everything is possible. Well I really hope so  

Greetings to all of you guys, Simon

p.s. If my english is a problem, please say so - I'll rephrase


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## Palladium (Jul 26, 2011)

dorki22 said:


> p.s. If my english is a problem, please say so - I'll rephrase



Your english is better than mine.


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## Harold_V (Jul 28, 2011)

Simon,
Old river beds can be a wonderful source of gold, assuming you can extract it to your satisfaction. One of my customers was recovering gold from the Green River, in Utah, although the bed was far from the course it ran at the time. It had migrated several hundred yards from the area that was being mined, and the gold was very finely divided. They used a serious of bowls mounted on a semi-tractor trailer to extract the values, which were gathered with mercury, then retorted. They provided me with the resulting cake. The gold ran about 94%, with the balance silver and a trace of palladium. 

Good luck with your venture, and don't worry about your English. It's much better than many that use it as a first language. 

Harold


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## Dirtdiggaler (Aug 17, 2011)

If you can't cuppel it you can't sell it!


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## geubrina (Oct 1, 2011)

Harold_V said:


> I just had another thought. I have a few specimens of the ore I processed that assayed over 300 ounces/ton gold. In these samples, there's an abundance of iron pyrite, which, to the untrained eye, looks a great deal like gold. Fortunatly, right along side the pyrite is a band of gold. The color difference is astounding. Pyrite has a rather dull yellow color, leaning even a little gray, while gold has a rich yellow luster. Difficult to discern unless you have both of them present, however, unless you have an exceptional eye for colors.
> 
> Harold



Harold, old friend, it is surely lead ore with high gold content? We have much of this ore, I even exported several containers to china, hahhahahaha... But ours is high silver content 400-1000ppm of silver.
Teach me, old Harold, how to refine this things....


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## Harold_V (Oct 1, 2011)

geubrina said:


> Harold, old friend, it is surely lead ore with high gold content? We have much of this ore, I even exported several containers to china, hahhahahaha... But ours is high silver content 400-1000ppm of silver.
> Teach me, old Harold, how to refine this things....


It was somewhat obvious to me that the ore in question did contain lead--as galena, and it, too, was high in silver. I had less than good results extracting the silver, however, leaving behind roughly 50%, as I recall. That wasn't an issue in my case, considering that silver, at the time, was quite low in value (well under $4/ounce), and the owner of the ore wasn't interested in silver recovery, only the gold. The process I developed performed exceedingly well in that regard, leaving but hints of gold in the waste. 

I'm not convinced what I did would work for you, but I'll gladly share what I learned. 

The ore was provided to me crushed to ½"-, which was then fed to the ball mill




Note that there was a classifying screen at the end of the chute. Anything that didn't pass the screen was returned to the mill for further crushing. Only a tiny percentage was returned, for the mill did an excellent job. I could control discharge rate by controlling the rate water was introduced to the mill. That prolonged crushing time. 

The classified ore, now reduced to fine powder, was then processed in the agitation tank, using cyanide and bromine. Extraction time was quite long, due in part to gold particles being somewhat large. If memory serves, I ran the material for a grand total of about 145 hours.




The pregnant solution was separated from the gangue by using the filter press




Recovery of values was accomplished with zinc flour. Sorry, I have no pictures of that process. 

Hope this helps. Be advised, you likely will not need bromine. In my case, cyanide, alone, would extract only traces of gold. It is for that reason that I suspected the ore was a complex---gold telluride. Not being a chemist or being versed in geology, I was not able to make reliable determinations. 

Harold


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## Reno Chris (Oct 9, 2011)

A very interesting small scale process line. 

Did you try to recover any of the coarser gold before leaching?

It would have saved time in the leach tank.

Chris


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## Harold_V (Oct 9, 2011)

Reno Chris said:


> A very interesting small scale process line.
> 
> Did you try to recover any of the coarser gold before leaching?
> 
> ...


Yes. I screened inside the ball mill, so nothing larger than about 1/8" could exit. I accomplished that by inserting a single row of steel dowels spaced accordingly. 

Once the material made it out of the mill, there's a screen between the discharge and the chute. It's the green thing you see leading to the bucket. Opening of the screen was, roughly, 1/16", and I recovered quite a bit of gold there. The chute was made of copper and covered with mercury. I discovered immediately that the gold would not amalgamate, so I built a final classification screen, which you see at the bottom. I simply wiped down the chute as best I could, then used it as nothing more than a conveyance. 

A great deal of gold was recovered on the final classification screen, although the vast majority of free gold was quite small in size. Aside from the obvious material, I had to magnify 400 times to see the gold. The ore, where it had a general gray look, was riddled with these tiny particles. That is what lead me to build the ball mill and agitation tank. I had no clue how to go about recovering the values, after opening my big mouth and telling the owner that I could do the job. (very heavy sigh!)

By the way, according to the final assay, the four 5 gallon buckets of ore were reduced in gold value to about $15. I got excellent extraction (99.55%), due in part to the prolonged running time. It operated without attention aside from taking samples and titrating, so I could maintain the proper pH and free cyanide level, along with the correct amount of bromine. 

All in all, a very good learning experience. 

Harold


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## Genesis (Oct 17, 2011)

CornFed said:


> Harold_V said:
> 
> 
> > RobertPress said:
> ...


Very well said about the assays. You can send out 5 samples of the same material to 5 different assay companies and you get a diffent assay from each of them and wide spread values. The assay companies are crooks in my opinion. If your not Newmont or Barrick your in for a ride that cost you money. 
The assay companies around here are greedy and have now placed a minimum of $200, $300 and $500. That's to squeeze the little guy out in my opinion. Those are Inspectorate, American Assay and ALS Chemex. I think those outfits are just prospecting tools for the big boys like Newmont and Barrick. Most of these companies have a cookie cutter way of doing things and most of the lab techs are students in training. Why not learn to do your own assays and save time and money. I'm learning that myself and having fun with it. 
From here on out I will do my own assays. I don't trust most of the assay companies at all. 
However, if your looking to fund your project, you are at the mercy of the assay companies. You will need third party certified assays to even think about funding a project.


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## Genesis (Oct 17, 2011)

Very Nice set up you have there. 
Did you build the press or buy it? 
I love to see all the DIY equipment that people build. Great stuff and thank you for your pictures and time.


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## Reno Chris (Oct 17, 2011)

> The assay companies are crooks in my opinion. The assay companies around here are greedy and have now placed a minimum of $200, $300 and $500.



We recommend assays because many guys decide they have gold based on their personal opinion and belief, not any actual scientific results. Many miners dislike assays as they are expensive and often dont give the results they want to see. If the assayers dont want to do business with little guys, that is their choice - its a free country and they are free to make make those business decisions. I can tell you you are totally wrong about them - they are in business to produce accurate results, they are not crooks. If you want to do your own assays, great, have fun.


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## Aristo (Oct 17, 2011)

Chris,

I have to comment on your statement: *"I can tell you you are totally wrong about them - they are in business to produce accurate results",*.
They are in business to make money. If they have to do 20 tests to give you a particular result, then they will instead of doing 5 tests. And of course they will keep charging you.
Its quite similar to law practice. Why would a law firm try to end a case in 3 months when they can extend it indefinitely, while charging his client and keep dazzling him with garbage?.


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## eeTHr (Oct 17, 2011)

Aristo---

Of course a business must make a profit, otherwise it wouldn't be a business for long.

But people with experience can usually sense when something isn't right, especially over a period of time. All it would take would be the submission of a known material, which was witnessed and documented, to know for sure. Several tests of this type, over a period of time, would make it certain. And that would ruin the reputation of any company.

From what I understand, there are a number of people who do their own assays, yet need third party documentation for specific reasons. Inaccuracies would become evident.

There is a difference between evidence and "just guessing." The only purpose for hunches would be to give possible reason to make tests, as stated above.

If you feel strongly that you are being ripped off, then make some documented tests, and sue them. Or just publish your tests appropriately.


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## Reno Chris (Oct 17, 2011)

> They are in business to make money.



Agreed. Assayers are not a charity operation. Yet like most businesses they must focus keeping their customers happy and producing a good product. For them a good product is an accurate result - that's what people come to them for. When I was actively involved in the Mining business, we always used umpire assays to double check the accuracy of our standard assayer. We never had any problems, but this is accepted industry standard practice to re-check a certain percentage of the assays, and of course we never told the normal assayer which ones we were re-checking. Produce a good product at a competitive price and treat your customers right and you have a good chance being successful in business (true for many types of businesses).

As far as excessive testing, I think that would be a rare problem. In the industry geologists dont come to assayers and ask - Which tests do you think I ought to run on this material which might be ore? I've never done that. I come in and say I have X samples here and I want them analyzed for gold and silver by fire assay (or whatever elements I want them to look for) - I know the methods they use, and can request the appropriate treatments to accomplish what I want. Its like ordering off a menu - only certain items are available. Lawyers get a lot of - "What do you think of my case? Do you think I can win?" Certain lawyers with limited scruples may answer that the case is great even if its not. But few professionals will go to an assayer show them some rock and ask - Do you think I should get these assayed? - That kind of opinion is really not their normal job.


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## Aristo (Oct 17, 2011)

Wow.
Who is getting ripped off dude?
Eethr,please relax. My comment was based on factual information and tangible evidence. In the unlikely event that I have issue with an assay or tests from an analytical laboratory, I am quite capable of formulating a measured response. You may have missed the whole point of my comment.


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## Aristo (Oct 17, 2011)

Thanks for that informative and thoughtful response Chris.


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## eeTHr (Oct 18, 2011)

Aristo---

It was the comparison to lawyers which slanted it to the way that I perceived it.


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