How is Cyanide used in mining?

There are two types of cyanide-leaching processes used by the modern mining industry. Vatleaching, where extracted ore is combined with cyanide in vats, and heap-leaching (described below).
Cyanide-leaching allows mining companies to reopen and expand mines containing what were previously unprofitable mineral reserves. The heap-leaching process, more commonly used than vat-leaching, involves - · digging enormous pits, so large they could swallow cities, and piling the extracted ore into heaps that would cover many football fields several hundred feet high; · spraying a cyanide solution over the heaps so that the cyanide trickles down through the ore, bonding with microscopic flecks of gold or silver, whereupon a heap pad (a rubber blanket) underlying the heap channels the solution into a holding pond; and · stripping the solution of the precious minerals, recovering the used cyanide, then respraying the cyanide solution over the heap. In the extraction of copper, nickel, cobalt and molybdenum, cyanide is used during the milling and concentration processes.
Learn more about: http://www.goldcyanide.com