The EPA is late coming to the game. There has been numerous studies and in fact the mine owners have admitted that just the creation of the mine will indeed destroy a lot of the salmon habitat by removing streams. Add the fact that they will create tailing ponds which will hold thousands of tons of toxic waste forever. This area is prone to earthquakes and the release of this battery acid like crap will destroy whatever it comes into contact with.
I would suggest for anyone interested in this is to search for Pebble Mine on Youtube and watch a few of them. There are some treehugger videos but there are some good fact based ones as well.