The major drawback is that it could negatively impact the last remaining major Salmon spawning region, and an ancient way of life connected to the fish. A huge project beyond anything that has ever been done, and the scale of protection required would be beyond precedent. Watch the entire video, it does present both sides. Do you turn it into a mining region or not? Allowing the mine would likely pave the way for others, was stated. An interesting positioning by the EPA. Some great scenery in the vid.