JUNEAU — Backers of a proposed copper and gold mine near a major salmon fishery in Alaska are taking another step toward advancing the project, as critics vow to continue fighting the effort.

Days after announcing it had found a potential partner, the Pebble Limited Partnership said Thursday it is submitting a permit application for the proposed Pebble Mine with the U.S. Army Corps of Engineers.

The application is the first step in what could be a years-long permitting phase for the hotly debated project, which got a boost earlier this year when the U.S. Environmental Protection Agency, as part of a legal settlement with Pebble, announced plans to lift restrictions proposed by the Obama administration on development in Alaska’s Bristol Bay region.

Pebble saw the proposed restrictions as an attempt to pre-emptively veto the mine project — before it had gone through a permitting process. EPA has yet to formally revoke the proposed restrictions.

Pebble CEO Tom Collier said the project met its major objectives for the year and said he is “ready for this next chapter in the Pebble story.”

The Bristol Bay region produces about half of the world’s sockeye salmon. Critics say building a mine there is too risky, and they sought to downplay Pebble’s announcements this week.

“To me, it was bare minimum of what they needed to do to keep their promise to their investors and to save face,” said Taryn Kiekow Heimer, a senior policy analyst with the Natural Resources Defense Council.

The company had expressed confidence it would have an investor and would go into permitting by year’s end.

On Monday, Northern Dynasty Minerals Ltd., which owns the Pebble partnership, outlined general terms of an agreement with First Quantum Minerals Ltd., under which First Quantum would help bankroll permitting costs and have an option to acquire a 50 percent interest in the Pebble partnership. The deal has yet to be finalized but calls for an initial investment of $37.5 million to go toward getting the permitting process going.

Both Northern Dynasty and First Quantum are based in Canada.

Northern Dynasty has been looking for a new partner since Anglo American PLC announced it was pulling out in 2013.

Heimer said her group will try “with everything we’ve got in our arsenal” to convince First Quantum that “this is the wrong mine in the wrong place” and that the company won’t get stakeholder support for the project.

Pebble said it plans to submit the permit application to the Army Corps of Engineers on Friday. Once the corps determines that the application is complete, or has all the required elements, the company said it will publicly post a detailed project description.

Collier said in a release that the proposed mine will be smaller than one earlier envisioned “with enhanced environmental safeguards.”

The corps is just one of the federal or state agencies that Pebble would have to go through as it pursues the project.