Rudy(CA) said:
It seems to me that in order for the compound to be "smellable", they would have to be volatile. Does anyone know of
a naturally occurring volatile compound of gold?
Hi Rudy,
I can smell the smell of cyanide in a cyanide treatment plant. The smell is not strong, but I think a dog or a machine could smell it better.
In my example above, you will not be able to smell any gold compound because the gold becomes a metallic gold molecule by combining with itself by the time it reaches the surface. What you would look to smell are the molecules it was combined with before it left them and neutralized just below the surface. In order to locate the gold, you would locate the molecules you suspect the gold was chemically combined with when it was deeper. And you must choose chemicals which are unique to gold, because this is the only indicator that gold was there.
The known chemicals are cyanide which is produced by bacteria, low molecular weight organic acids which are produced mostly by plant roots and decaying organic matter, and sulphur complexes which suspend the gold ions during their migration. We would be looking for the remnants of these molecules after the gold has left.
I would expect the cyanide is mostly not volatile, but probably a small amount of sodium or potassium cyanide salt could become airborne. I would also expect small traces of the cyanide would become hydrogen cyanide, and become airborne where it could be smelled. I don't think this would be in toxic amounts, but probably would be smellable by a dog or a machine. This cyanide is produced by bacteria which establish colonies when they find a metal to attack. Only a special kind of bacteria that thrives in toxic environments will grow a colony here, which means any anomaly in the cyanide is an indicator of buried metal. The problem is it is not only for buried gold. It could mean platinum, copper, iron and a quite a few other common metals. I suppose you would need to use your intuition to determine what kind of buried metals are expected to be found in the area.
More likely to be on the volatile side are the organic acids associated with gold. These would not necessarily indicate gold, because they are in the soil whether gold is present or not if you have the necessary decaying organic matter or plant roots. but in combination with the cyanide, these give evidence there is one transport/suspension medium in the soil.
Then there are the sulphur complexes. Gold is not suspended only in sulphur complexes. It can also be suspended in other complexes such as arsenic, antimony, and others, depending on what's in the soil. I don't think it's possible to predict what you will find left over at the surface after the gold has left the complex. I think you would find a number of salts which represent what was under the ground.
It seems to me this is where the research is needed to identify what exactly remnants of this gold ion transport and chemistry is found at the surface, and what we can count on finding that most reliably indicates gold is there. As far as the volatility, I am thinking that even a salt will be smellable considering most people can smell the salt air when they come from an inland area to an ocean beach. Even if there is no salt mist in the air, I would think the normal humidity in the soil is enough to release some aquatious salt molecules from the ground into the air where a dog could smell it. If this is so, then the organic acids and HCN would be much easier to smell than the salts.
When I review this smelling gold idea, it is beginning to look like maybe there are easier ways without all this troubling research. I am wondering if it isn't easier to let the dog figure out what he needs to smell to find gold. Then give him a really big reward when he gets it right. And if that doesn't work, look for a different way to find long range detection.
Best wishes,
J_P