Several Democratic members of congress are asking federal agencies to turn over documents related to 2018 decisions that pushed copper-nickel mining forward near the Boundary Waters Canoe Area and Wilderness.

In a joint letter Friday, chairs of the House Energy and Mineral Resources Subcommittee, the House Natural Resources Committee and House Interior and Environment Appropriations Subcommittee berated several decisions made by the United States Department of Agriculture and Department of Interior in 2018, including the end of a mineral withdrawal proposal in the Rainy River Watershed and Superior National Forest and the renewal of Twin Metals' mineral leases.

The letter, signed by Raul M. Grijalva of Arizona, Betty McCollum of Minnesota and Alan S. Lowenthal of California, requested the agencies provide all documents regarding those decisions by April 1.

"The abrupt cancellation implies that the mounting evidence against mining that emerged did not support your position, and so, you instead chose to waste taxpayer funds, ignore public comments, and suppress scientific information rather than have this evidence revealed to the public," the letter said.

Opponents of the project fear toxic sulfide would pollute the nearby BWCAW while supporters say it would help bring much needed jobs to the region.

The Trump administration has long pushed to reopen the Superior National Forest for mining.

Ordered by the Obama administration in 2016, the mineral withdrawal was intended to help federal officials decide if about 234,000 acres of the Superior National Forest outside the Boundary Waters Canoe Area Wilderness should be exempt from all mining activity for 20 years.

In Jan. 2018, the U.S. Forest Service, a branch of the USDA, announced they would not conduct an environmental impact statement, the most-thorough level of environmental review of potential copper mining impacts, on the BWCAW as part of the mineral withdrawal, and would instead conduct an environmental assessment, a less-stringent study.

At the time, U.S. Forest Service officials said that, if the environmental assessment turns up new evidence of more serious environmental consequences, a full-scale environmental impact statement still could be ordered.

But by September, that plan was axed, too. At the time, a U.S. Forest Service spokesperson told the News Tribune the environmental assessment would not be completed because a "science-based analysis" with public input showed no need for further environmental studies.

The letter also took swings at Twin Metals, a wholly owned subsidiary of Chilean mining conglomerate Antofagasta, which won back critical federal mineral leases in May 2018 previously withheld under the Obama administration.

Twin Metals is planning an underground copper-nickel mine along the Kawishiwi River near Ely, within the Rainy River Watershed and on the edge of the BWCAW. The company intends to store tailings near Babbitt, which is in the St. Louis River Watershed.

"For more than half a century, Twin Metals and administrations from both parties have questioned the economic and environmental feasibility of hardrock mining leases in the Rainy River Watershed," the letter said. "Which begs the question: why push this operation now?"

Twin Metals did not immediately respond to the News Tribune's request for comment.

Opponents of Twin Metals and mining near the BWCAW said the letter was needed.

"It is high time the American people got answers on what the Trump Administration is hiding," Becky Rom, national chair of the Campaign to Save the Boundary Waters, said in a statement Friday.