I learned about the Pebble Mine project in Bristol Bay when I lived in Alaska in 2010-2011. This image tells of some of the problems with the mining project, including the need to manage the waste for “hundreds of thousands of years.”
Here are a few more quotes from the adn.com article:
“The mine footprint would be enormous. The pit would be nearly as deep as the Grand Canyon. The pit, tailings dams of processed ore, and waste rock piles would cover an area larger than Manhattan ... the deposit is in the watersheds of two major salmon rivers, which together support about a quarter of the world’s wild sockeye salmon, according to EPA.”