FEAR!  FEAR!  FEAR!  That is what this is all about!  And it's unfounded.  I have worked in the oil, mining, and construction industries during my 44 years as an Alaskan residence and have yet to see the devastation that so many fear, with the exception of the Exxon Valdez oil disaster(and even that was not a failure due to infrastructure failure but the failure of two US Coast Guard members and the Co-Captain of the vessel).  Working at Red Dog Mine is a classical example of safeguards in place that prevent disaster.  If Pebble mine is developed, then make sure the Civil and Structural Engineers design a facility that is not going to breach the tailing by-product which could possibly contaminate the Bristol Watershed (and let me emphasize could).  Furthermore, why not design a facility with a slurry transport system carrying the tailings to the coast and transported out of the region all together.  My point is, there are many options to consider to prevent disaster.  Let it open!