Glycine is better known as aminoacetic acid. It's a low energy non essential amino acid. It's mostly used commercially to make the herbicide glyphosate (Roundup) and as a sweetener in some manufactured drinks.
With a formula of C[SUB]2[/SUB]H[SUB]5[/SUB]NO[SUB]2[/SUB] it's not surprising that aminoacetic acid has a similiar action to the cyanides. Most of the aminoacetic acid produced for commercial use has chlorine as a byproduct of the manufacturing process. (chloroacetic acid is treated with ammonia to produce aminoacetic acid)
Cyanide is not a single substance but is any of the many chemicals with a formula including the CN group. The cyanide used most commonly in mining leaches is hydrocyanic acid (HCN). (methane is treated with ammonia to produce hydrogen cyanide)
If you look at the formulas you will see that the two acids are very similar. Both are poisonous in concentration although hydrogen cyanide is much more so. Aminoacetic acid has a sweet taste that is very attractive to animals and children.
In mining there is no single solution to leaching ores. The large mining companies spend a lot of time customizing their leach processes to work on any particular ore. Leaching is a process because the leachate must be recovered and conditioned to be used again and again. No mining operation just uses a leach and discards it - they would go broke after the first batch. Miners are the original and ultimate recyclers. They all try for 100% recovery and reuse of their leach chemicals.
To understand how critical recovery and recycling is to the leach process you need to study the principles of
redox.
Obviously leaching is not as simple as choosing a particular chemical and pouring it over your ore. The greenies would like to have you believe that cyanide is used willy nilly by the mining industry. There have been accidents but cyanide itself is only a poison when living creatures are exposed to the non depleted solutions. In mining the release of cyanide is completely contrary to it's intended use. No mining company wants to lose any cyanide solution in any of it's redox states whether enriched or not.
Aminoacetic acid might be the best choice for leaching some ores. It is not safe around children, animals or clumsy miners. It's just less dangerous than cyanide and in most cases less effective.
Learn more about the basics of leaching gold with redox process leaches.
If it was simple everyone would be doing it in their backyard.
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