Small-Scale Miners In Nariño Face Crackdown As Foreign Companies Set Sights On Colombia

They do not use toxic chemicals, but many small-scale operations -- and all large-scale ones -- in the country do use toxins.  It is no wonder then that Colombia has some of the highest levels of mercury contamination in the world. 

Ferney Gamboa argues that compared to his operation, a massive gold mine in the area would be far more detrimental to the environment. "A large-scale mine will have a much larger impact. These companies use cyanide and huge amounts of water." 
http://upsidedownworld.org/main/colombia-archives-61/3567-small-scale-miners-in-narino-face-crackdown-as-foreign-companies-set-sights-on-colombia