Mine owners claim that the mammoth project would have no impact on the fishery, but native peoples and commercial fishermen believe otherwise. Open-pit mines in general (Montana and Arizona come to mind), and those operated by Anglo-American PLC in particular (in South Africa, Zimbabwe, Ghana, Mali, Ireland, and the U.S.), have a long history of catastrophic degradation of the environment ~ not just the ugly scar of the mines and tailings, but also the leaching of toxic chemicals into the water table, polluting streams, lakes, and the ocean.
Further, the proposed site rests within an active geologic fault system. The 1964 Alaska earthquake, at 9.2 on the Richter scale, was the second most powerful quake ever recorded, orders of magnitude more destructive than the 2011 Fukushima earthquake which led to a nuclear disaster at a facility which purportedly was built to withstand earthquakes. If open-pit mines have demonstrated problems with habitat destruction and toxic waste seepage under normal conditions, Is it even possible to guarantee the integrity and safety of operations in the event of a massive earthquake?
The salmon fishery is the last remaining pristine salmon run in North America. The reason for its existence is simple ~ the streams and lakes which host the salmon spawning runs have never been disturbed by human industry. The Pebble Mine owners would like to change that, and Alaskans are deeply divided over the prospect. Statewide, in 2006 28% of Alaskans favored Pebble, while 53% opposed it. In the Bristol Bay region, 20% of residents favored the mine, while 71% opposed it. As is commonly true when an outside agent wants to extract the natural resources (or limit the management of game species) of a sparsely-populated state, some residents see only the promise of jobs and wages, while others see it as an invasion of their home turf. The mining company in question is controlled by Canadian, British, Australian and Japanese interests, not by U.S. interests.
I urge, I implore you to view the entire 54-minute episode. The images of Alaska's magnificent landscape and its wildlife are superb, and the discussion of the implications for both humans and for nature is intelligent and absorbing. You will see parallels with other "development" controversies, e.g. the Keystone Pipeline. And you may be faced with questions that have no easy answers ~ though for me the resolution is clear and unambiguous. When in doubt, protect wilderness and wildlife. We have too little left, and more disappears daily.