# Gold and Silver recovery from tailing dump



## kjavanb123 (Apr 1, 2009)

Hi

I have posted this in another threat, so I thought it would be good to add this as a seperate post.

There is a tailing dump from a copper leaching plant. It is estimated to be 5 million metric tons. I think they are already 200 mesh, so no crushing or ball-milling required. Somone extracted gold and silver from 4kg, and 67kg samples from this tailing dump, but obvioulsy wouldn't let me know about the detailed process. But according to him, it first smlet the tailing sample, with some sulfide lead ( from old car battery ) then remove the siclicum leyer from the rest, and the rest is being resolved with Nitric acid using a rectifier to extract the gold, and AB acid ??? to extract the silver.

He mentioned he uses sulfied lead rather than pure lead.

Since he is not a trustworthy person to do business with, I like to know from memebers with experties in this area. How can I start a small-scale mining the tailing dump for gold and silver? I assume no milling needed as it is already milled and crushed, just the chemical process. Willing to take samples to anywhere to be tested. also joint-venture is welcome.

Here are the photos related.


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## Lou (Apr 1, 2009)

How many grams is that larger one?


You need to find out how many grams are present per killogram/metric ton. If we know that then we can better assist you with the best method.


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## semi-lucid (Apr 1, 2009)

Hello

Did you say in the other thread that you are in Pakistan?

Was the ore leached with cyanide?

There may be cyanide compounds that could be liberated to toxic gas if you do the wrong thing.

Smelting does not sound practical to me. I would guess cyanide leaching would probably be most practical, but it requires competency and equipment to do it safely.

I am far from being an expert, but you might have to become an expert, if your going to process that material safely.


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## kjavanb123 (Apr 7, 2009)

Lou said:


> How many grams is that larger one?
> 
> 
> You need to find out how many grams are present per killogram/metric ton. If we know that then we can better assist you with the best method.



Dear Sir

Thanks for your respond. I have 3 lab reports, so I am not sure the exact numbers for Au and Ag. A Lab from China reported 2ppm Au, and 76ppm Ag. Another Lab in Pakistan reported only 0.2ppm Au and unknown Ag, and person who actually produced the gold you see in the pictures reported 12-20ppm Au, 50ppm Ag. 

I am sending a sample to Acme Lab Canada as I have heard they are pretty good, just have to decide between fire assay or ICP mass.

Also the tailing is from copper leaching plant with Calchopyrtie ore being the main ore that is processed. 

Those mentioned analysis also indicated 67% of the tailing is SiO3, some Fe and Mg.

Hope that helped, please advise small-scale operation to process this 5 million tons of waste.

Thnx
Kevin


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## kjavanb123 (Apr 7, 2009)

semi-lucid said:


> Hello
> 
> Did you say in the other thread that you are in Pakistan?
> 
> ...



Hmm my guess is they use some sort of acids to leach the copper from calchopyrite ores. 

Thanks
Kev


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## kjavanb123 (Apr 11, 2009)

Hi all,

in regards gold/silver extraction from tailing waste, the person who got that gold in picture has told me about his latest methods of extraction. It uses electric furnace to just evaporate the soil containing silica and the rest of unwanted stuff, and work on the remaining which is mostly precious metals. Hmm he is pretty cool, I just gave him 30kg of tailing sample. This is huge business considering his numbers and total quantity.

I will keep you posted with the updates.

Thanks
Kev


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## aussco999 (Apr 19, 2009)

Kevin:

I think your assay info will be to unreliable to be of much use to you. The problem is the material has already been ground up, some metal extracted (???), then dumped as tailings. Therefore, any remaining heavy metals would not be homogeneous mixed in the tailing matrix. A grab sample or even a drilled core sample will produce no better results than a hit or miss assay. You need to examine this project from a completely different standpoint. Also, IMO and with much experience on these types of projects, there is more homework to be completed before determine the feasibility (profits) of this project.

First, you need all the information on the original process, including the mineralogy of the original ore. Also, in what form and particle size was the gold; associated with sulfides, free gold, micron. If this was a copper leaching project, they normally use a diluted sulfuric acid liquor to extract the copper, leaving the other heavy metals behind. If they did use a cyanide leach (which is very doubtful, as cyanide is not used on sulfide ores unless first roasted), then most of the gold has already been extracted.

I have doubts this was a leaching operation, because of the material’s fine grind. It sounds more like flotation extraction, which works very well on sulfide ores. Keep in mind heap leaching doesn’t work well on a fine grinds because of channeling. If it was, then some kind of agitating system, with a CIL/CIP extraction system would have been used, and that’s not cheap. And, to smelt/melt a ton of material (including handling, environmental, etc), to recover a few grams of gold would be very expensive, unless another saleable secondary product (glass, ceramic clay) was produced to help cover the costs.

There are so many things to consider when looking at a new project, but here is a short list to consider; property/mineral ownership and accessibility, power (electric or gas), available water and required treatment, manpower, a means of handling (load/unload) the material, and the extraction and recovery systems. And the list seems to go on forever.

Because your material is already finely ground, you might consider a small pilot plant using some of the gravity recovery equipment available that are designed to recover micron sized particles of heavy metals, such as; jigs, HF tables, centrifugal bowls, elutriation towers and maybe even a floatation system. Chemicals used to recover sulfide ores by flotation suppress free gold and sends it to the tails. By changing the chemicals, you can re-float the gold and suppress the gangue material. The good news is, after the initial equipment set up, floatation is a cheap, safe, effective, fast and high-tonnage process.

Forget about the secret “black box” recovery systems, the only person making any money is the guy selling the gizmo. If you really have an economical amount of gold in your material, the equipment systems already exist for it’s extraction. 

If I can be of some help, let me know. And keep us informed of your progress.

John


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## kjavanb123 (Apr 20, 2009)

Hi John,

Thanks for this comprehnsive respond. They use flotaion to recover copper ore, and the gold mostly in sulfide ore with chalchopyrite. They do not use cyanide leaching, only diluted sulfuric acid. Original ore body contains 2-40ppm Gold, and up to 600ppm of silver before ore is being processed. 

Now I have searched the net, and they all say agigated cynaide leaching is best for recoverying gold/silver from tailing dump. any other methods used? 

Thanks for the advise.


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## goldsilverpro (Apr 20, 2009)

What is the pH of the material? I would want to know that before attempting to use cyanide.


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## kjavanb123 (Apr 20, 2009)

goldsilverpro,

i just recieved information regarding the chemics used in copper flotation plant that produces the mentioned tailing dump, it's as following

ABC 250 oil,
Pine oil,
isotanic oil

They never used cyaniade, they have used lime in the past for a short period but not anymore, but the chemicals are being used right now.

In order to find out more about where the gold and silver from the ores are going i was thinking to analyze the copper concentrate (20% Cu ) that they produce, and compare it with analysis of tailing dump. If there are more gold and silver in the copper concentrate then they extract them during the process, and if there are more precious metals in tailing than it is in copper concentrate then we better off processing the tailing using agitated cyanide solution.

Thanks all for your inputs.


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## kjavanb123 (Apr 20, 2009)

All concerned,

This is also a good link of similar mine to this one. 

http://www.mindat.org/loc.php?loc=122266&ob=4

Type of extraction originally used: Underground tunnels, mostly orebodies are being extracted.

Efficency of extraction processes: Nothing has been changed since 40 yrs ago when they started extracting and flotation to produce copper concentrate.

Age of tailing: about 40 yrs.


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## peter i (Apr 21, 2009)

... be careful out there!

Whenever somebody is able to recover more value than the analysis indicated to be present, and refuses to divulge the method, a little bell should start to chime!

(I know, I'm just paranoid ;-) )


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## Harold_V (Apr 21, 2009)

peter i said:


> .(I know, I'm just paranoid ;-) )


No, you are not. Those words are to be seriously considered. Scam artists work in many ways-----

Harold


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