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Do you Leach? What is your favorite solution  

18 members have voted

  1. 1. What is your favorite gold leach solution?

    • Agua Regia
      0
    • Potassium Cyanide
    • Potassium Iodine
    • Never done it - don't know


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I was reading on another forum about a gold miner being found dead among "toxic chemicals that could cause an explosion", which made me want to ask the question, "What are your favorite gold leach solution?".

I created a poll question. Whats your favorite solution?


HH
Mike

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Same as LipCa. I only know one guy who has. I was camping with a bunch of prospectors and the subject was brought up,and Don Robinson went into great detail. It was fascinating,but a little over my head...was like listening to Tom D. talk algorythms,lol.

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Where's the option for "none"

 

I wouldn't expect many on this forum to "leach" as it is primarily a detecting forum.

I go with "None" also. If I can't find free milling gold in a vein, I look for another. Leaching is usually not profitable or worth the risks for a small miner. Sometimes a rich sulfide or telluride ore can be roasted and then crushed and panned. Cost is only fire wood and no chemicals to buy. However, "Don't breathe the fumes coming off the roasting ore."

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Sorry have been slow in making reply on this and a couple other threads. The been out of town for almost two weeks and am catching up on things that didn't get done while I was gone.

 

Generally speaking, individual prospectors have no reason to be doing any leaching. While it's true something like 80% of the world's newly mined gold comes from cyanide leaching operations, the big commercial operations are hugely different than ours. Gold specimens with visible gold such as we might find with a metal detector take forever to leach because the process to dissolve the gold is slow. This is why mining companies that work with cyanide process ores with tiny or even microscopic gold particles. If there is any bigger gold in there ore, they use gravity equipment circuits to capture that larger stuff. Bigger, easily visible particles of gold such as even the smallest pieces which could be found with a high-frequency VLF or recovered by a gold pan or dredge take a year or more to dissolve in most leach solutions.

 

This is a topic on which one could write many books, and there are whole books on the subject. I did a whole article on alternative leeching solutions for the ICMJ prospecting and mining journal about a year ago. While some are less toxic than cyanide, most of these alternatives are toxic in their own right - it's just a matter of how much or how little material it would take to kill you.

 

I get questions about leaching black sands, and I tell people over and over that the only gold in 99.9% of all black sands is tiny particles of free gold which can be recovered by other methods like the blue bowl, etc. The truth is that in nearly every case, there is no magic gold locked inside the particles of black sand which can be recovered by leaching. individual prospectors are thinking about processing small amounts of or by leaching, but even rich ores would require you to leach tons of material to get a decent return. This is why very few individual prospectors get into leaching in any form and why it remains the domain of large commercial operations.

 

Chemistry is a difficult subject and most people don't want to get into the technical aspects of it, but if you go and mess around with chemicals you need to understand what you're doing - and not just in a cursory way that the seller gave you a 5 minute instruction on use as you're going out the door with his product. Even standard cleaning products that we have around our homes, if you mix the wrong ones it can easily kill you. Liquid bleach and ammonia, two very common cleaning chemicals mixed together produce deadly chloramine gas. Many toilet cleaners and pipe cleaners like Drano are highly acidic, and if you mix them with bleach will produce deadly chlorine gas. There are a fair number of people who die each year in household accidents in the USA from mixing standard cleaning products which should never be mixed.

 

Potassium iodide, listed above as one of the "leach products" in this poll does not dissolve gold or silver. It is used as a stabilizer with elemental, free iodine. It is the free iodine  that can dissolve gold. Iodine will however, not dissolve silver as silver iodide is insoluble.

 

Cyanide is of course what virtually all the mining companies use. Believe me, if they could come up with a non-toxic easy to use alternative, it would have been in use decades ago. The big mining companies Have teams of chemists and do spend a significant amount of money on research and development. Cyanide is used because it is low cost, captures both gold and silver, and is safe if handled properly by folks who know what they are doing.

 

As Steve said, I set up and ran a small heap leaching operation in Nevada in the early 1980s. We were careful and never had any problems with the cyanide that we used, but we were prepared with chemicals to neutralize the cyanide and treatments in case employees were accidentally exposed. Like most mining companies using cyanide, those safety measures were never necessary but we had them on hand just in case.

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As a side note, black sand might be sold to amateur blacksmiths who need raw iron ores to make homemade knives, and other items with , I have discovered recently. They may even have blacksmithing clubs. Something to do some research on. I am staying clear of cyanide  or any homebrew chemical solutions for gold recovery.

 

-T

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If I had ounces and ounces of fines, I'd probably play around with some aqua regia and then cast my own PAMPs if not for the cool factor of having my own gold bars. At least I'd know exactly what I would be getting from a refiner if I were to sell them.

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In 2014, I removed the gold plating from a bunch of electronics. It is very possible and even common to digest some of the underlying metal and loosen the gold plate so that it can be separated. The attached photo shows about 1/2 ounce of gold plate I separated from those electronics in the spring of 2014.

post-5-0-09602200-1420479299_thumb.jpg

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