JUNEAU — The U.S. Army Corps of Engineers is proceeding with an environmental review of a proposed copper and gold mine near a major salmon fishery in Alaska, despite a request from the governor that the review be halted.

Gov. Bill Walker, in a letter co-signed by Lt. Gov. Byron Mallott last month, said the company behind the proposed Pebble mine had yet to show that the project is feasible or realistic. They argued that, at a minimum, a preliminary economic assessment should be conducted to help inform the corps' work.

But Shane McCoy, the Corps' program manager for the Pebble review, told reporters Thursday that an economic analysis is not required for the corps to do its work.

There are limited situations in which a review would be halted, including cases in which an applicant itself asks to stop, or if an applicant fails to provide the Corps requested information, McCoy said. Walker's request was not one that the corps could grant under its rules, he said.

The Pebble Limited Partnership, which wants to develop the Pebble mine, has given no indication that it wants to suspend the process, McCoy said.

The Corps' position was explained to Walker directly by the commander of the Alaska district, Col. Michael Brooks, he said. Austin Baird, a spokesman for Walker, confirmed that Brooks and Walker spoke and Brooks indicated that he "would not honor the governor's request."

Tom Collier, CEO of the Pebble partnership, last month said the company believes it can "successfully and responsibly" operate the mine. "This is what the Corps will evaluate and we can either meet this expectation or we cannot," he said in a statement.

Collier called Walker's request to suspend the review a stall tactic.

The Pebble project is in Alaska's Bristol Bay region. Bristol Bay produces about half of the world's sockeye salmon.

Debate over the project has been politically charged, with critics contending it is the wrong place for a mine and supporters urging the project be vetted through the permitting and review process.

In a statement earlier this year, Walker, an independent, said the Bristol Bay region "has sustained generations and must continue to do so in perpetuity."

Baird said Thursday that Walker "continues to believe that the Bristol Bay watershed is unique" and that the proposed mine "must be held to an extraordinarily high standard."

Republican U.S. Sen. Lisa Murkowski, who chairs the Senate energy committee, has said she expects "a fair, rigorous and transparent process" that will help Alaskans understand "the impacts and risks, as well as the potential benefits associated with this project."

The Pebble partnership is owned by Canada-based Northern Dynasty Minerals Ltd., which has been looking for a partner since Anglo American PLC announced it was pulling out in 2013.

First Quantum Minerals Ltd. was courted as a potential investor but backed away from the project in May.