In a high-stakes battle that pits gold and copper against fish, members of Congress are scrapping over a plan to build one of the world’s largest open pit mines in southwest Alaska.

Fearing that toxic wastes from the mine could hurt the wild salmon population in her home state, Washington Democratic Sen. Maria Cantwell intends to enter the fray Monday. She plans to ask the head of the Environmental Protection Agency to consider using the Clean Water Act – if necessary – to stop the proposed Pebble Mine project on Bristol Bay.