JUNEAU, Alaska (AP) — A group seeking to develop a massive gold-and-copper prospect near the headwaters of a world-premier salmon fishery in Alaska is suing the U.S. Environmental Protection Agency for taking steps that could result in development being restricted or prohibited.

The Pebble Limited Partnership alleges in its lawsuit that the EPA exceeded its authority when it initiated the rarely used process under the Clean Water Act after concluding that large-scale mining in the Bristol Bay watershed posed significant risks to salmon. Pebble fears the agency will kill the project before mine plans are finalized or it’s evaluated through the permitting process.