More than 40 U.S. House and Senate members have asked President Donald Trump to maintain protections for Alaska's Bristol Bay region, which produces about half of the world's sockeye salmon.
The Democrats, in a letter dated Wednesday, say a proposal by the U.S. Environmental Protection Agency to lift restrictions on mining in the region that the agency once pursued is egregious and illogical.
The letter, spearheaded by Sen. Maria Cantwell of Washington and Rep. Jared Huffman of California, seeks additional public hearings and comment time.
Public hearings were scheduled for Wednesday and Thursday in the Bristol Bay region ahead of the expected close of the current 90-day comment period next week.
In a statement, the EPA said it will consider all public comments it receives on its proposal and review the request to extend the comment period.
The stalled Pebble Mine project received new life when the EPA earlier this year said it would move to lift restrictions on development sought by the Obama administration as part of a legal settlement with the Pebble Limited Partnership.
The Pebble partnership is pursuing the mine and recently unveiled plans for a smaller project. Pebble has said it hopes to file a permit application in December.