The True Cost of Gold

Modern mining techniques require the use of great quantities of toxic chemicals because modern gold mines actually have only a minute concentration of the precious metal – usually no more than one or two parts per million. That is 0.0001%. Cyanide is usually used to leach gold from the ore while some smaller operations use the equally toxic mercury.  Even when all goes according to plan, the chemicals leak into the environment, killing wildlife and rendering water undrinkable. Things don’t always go to plan of course, and the countless accidents seen in the gold mining industry include major environmental disasters.  Containing pools spring leaks, poisoning entire areas. Gold mining also uses great quantities of water and energy, and the lower the grade of a deposit, the more water, chemicals and energy is needed.
http://begreen.botw.org/2012/10/the-true-cost-of-gold/