With successively lower temperatures as the water mixture cools, new sets of minerals are formed and many of those stable at a higher degree of heat became subject to alteration as the temperature progressively moved lower.

The non-toxic thiosulfate is actually the medical antidote given to people for cyanide poisoning. By accomplishing both neutralization and metals recovery, this process creates an economic and environmentally attractive process.

…we cheered and high-fived each other as the ore cart slowly crested the top of the headframe, then picked up a bit of speed on the short downhill section and came to an abrupt halt, ejecting its contents of ore…