I was privy to see Anglo American/Northern Dynasty original mine plan that was taken off the table once such strong opposition showed up. This is still their plan, they are just now trying to fool Alaskans that it will be a smaller mine now. 
 So it's a 2400 foot deep hole, removes lakes,creeks,streams and rivers, lowers the water table ( dah !, can't dig a hole with ground water that is just below the surface ) , there will be up to 5 containment reserviors, Mine will use the same amount of water the city of San Fransisco uses a day for ore processing, there will be a road to the Ocean that will have a large mining Dump truck passing by every 15 minutes. There will be acid mine drainage, any copper over 1 part per billion in the water effects salmon smolt  sense of smell ( scientific fact ). Northern Dynasty states they will try and replace streams removed by introducing salmon to other streams. 
Pebble is finely disseminated, so you have to dig up a lot of dirt for a little ore..