40,000 gold miners invaded Roraima. 15 Yanomami died as a result of the miners bringing malaria into Yanomami territory. Rivers have been polluted with mercury and gold miners are quickly spreading venereal diseases.
This article details the Yanomami Valley, which was under government supervision until 1996. Since the supervision was stopped, numerous gold miners have come to valley seeking riches and ultimately destroying the land for the people who live on it.