Washington Democratic Sen. Maria Cantwell on Tuesday called for the Justice Department to investigate whether Pebble Mine executives have lied to Congress and in documents submitted to the federal government about their plans for tapping into a massive gold, copper and molybdenum deposit in the Bristol Bay region of southwest Alaska.

The region’s freshwater rivers, streams and lakes support the spawning of the world’s largest sockeye salmon runs, which hundreds of Washington fishermen head north to Alaska each summer to help harvest. And Cantwell, for years, has been a critic of the mine and the risks that its development would pose to the salmon resource.

Cantwell’s request for the Justice Department investigation follows the release earlier in September of secretly recorded conversations of Pebble Mine executives by the Environmental Investigation Agency. These recordings indicate officials are contemplating a larger and longer mining operation than outlined in their 20-year permit application and that they have stated in congressional testimony.

In the tapes, Roland Thiessen, chief executive of the project developer, Canadian-based Northern Dynasty Minerals, said the project could last for another 160 years and eventually double its output. “Once you have something like this in production, why would you want to stop?” Thiessen said in one of the tape-recorded conversations.

Cantwell, in a statement released Tuesday, noted that in an October 2019 House Transportation and Infrastructure Committee hearing, then-Pebble Partnership CEO Tom Collier testified that “Pebble has no current plans, in this application or in any other way, for expansion.”

Collier, who was secretly recorded boasting about his relationships with politicians, has resigned from his position in the aftermath of release of the tapes.

Cantwell said the tapes indicate that mine officials may have lied on their permit application, deceived investors, and “possibly perjured themselves in front of Congress.”

Material from The Washington Post is included in this report.