Gold Mining threatens Yosemite, Groups Say

“These claims are close enough that the cyanide and other toxic chemicals they use to separate ore from rock could run off into the Tuolumne River and the trails and wildlands that surround it,” said Farrell, adding that only a tiny amount of cyanide is needed to kill fish and other wildlife
http://californiawatch.org/dailyreport/gold-mining-threatens-yosemite-groups-say-12772