The “El Mauro” tailings-dam is the biggest in Latin America, and third biggest in the world. It holds 2060 million tons of water and mining waste, and is over double the height of the London Eye. Severe risk of the dam collapsing in an earthquake, water pollution, its use of local water supplies, and the impact of mining on the local agriculture are the most central concerns about its installation.
See http://upsidedownworld.org/main/chile-archives-34/4335-qel-mauroq-tailings-dam-pits-community-against-the-oligarchy-in-chile.