Apparently the same firm- Knight Piesold- that designed the failed Mt. Polley dam designed the Pebble dam.  Even if the size is reduced from yuuuge to a mere behemoth, the potential of a catastrophic dam failure remains.

https://www.adn.com/commentary/article/our-view-murkowski-right-press-pebble-plan/2013/07/13/

Pebble kept procrastinating and procrastinating on a plan-so that they could say there was no plan for EPA to assess- to the point that Lisa Murkowski wrote to them back in 2013 urging them to release a plan.  Perhaps now at long last everyone will see their "new" plan in the coming years.

Since the settlement provides that "EPA may use its scientific assessment regarding the Bristol Bay Watershed without limitation," Pebble appears to have a huge hill- or dam- to climb, and still lacks a major investor for what promises to be a very expensive project with great public opposition.