The Trump administration on Friday curtailed a detailed review of how cordoning off more than 234,000 acres of U.S. Forest Service land in Minnesota from mining development would affect a neighboring wilderness area.

The decision to convert the study launched in the final days of the Obama administration into a less-stringent environmental assessment could have major policy implications. Last January, the Interior Department blocked mineral extraction for two years in the swath of forest near Minnesota’s Boundary Waters Canoe Area Wilderness, a glacially carved region west of Lake Superior that is speckled with lakes and popular with canoers.

At the same time last year, the federal government announced it would review whether to bar mining in the U.S. Forest Service-managed land for a longer stretch, the next 20 years. Interior officials decided not to renew existing leases for a copper and nickel mining operation there.

The action launched bureaucrats into completing hundreds of pages of environmental analysis — ultimately meant to produce a comprehensive document called an environmental-impact statement. The study aimed to assess whether a sulfide-ore mine, which can leach toxic metals, could potentially pollute more than 1,200 miles of neighboring streams in an area where the water flows south to north.

Forest Service officials said Friday that they will now conduct an abbreviated review of the Obama-era proposal to withdraw the land from possible mining.

“While the science indicates significant environmental impacts are unlikely to result from the proposed withdrawal, I am deeply aware of the controversy regarding socio-economic implications,” said Superior National Forest Supervisor Connie Cummins in a statement, adding that agency specialists “are working hard to ensure the [new study] accurately describes all the facts of the proposal, to aid the Secretary of the Interior in his decision.”

The decision reflected the input received in more than 90,000 comments, and would still constitute a “thorough environmental analysis” of the watershed, said Kathleen Atkinson, regional forester for the Eastern Region.

The switch to a less stringent review, called an environmental assessment, comes a month after Interior chose to renew the expired mining leases held by a Chilean mining giant next to the wilderness area. The Forest Service decision constitutes another small example of the Trump administration easing the way for more mining across the country — not just for coal, which Trump often mentions in speeches, but for ores of copper, nickel and other metals as well.

Reversing the Obama-era decision has been the subject of intense lobbying over the past year. Shortly after entering office, Interior Secretary Ryan Zinke meet with proponents of Twin Metals Minnesota, a subsidiary of the Chilean firm, which belongs to the family of billionaire Andrónico Luksic, who rents a Washington home to Ivanka Trump and her husband, Jared Kushner.

While Republicans in Minnesota cheered the reversal, saying it will be a boon to the economy of a state Trump only narrowly lost in the 2016 election, environmentalists and some Minnesota Democrats, including Rep. Betty McCollum, have pressed the Trump administration keep the withdrawal in place. They are concerned more mining could taint the waters that draw campers and drive much of the region’s economy.

Boundary Waters, which abuts the federal forest where mining would take place, contains lakes and streams that annually host 100 species of migratory birds, along with an active fishery.

“Interior Secretary Ryan Zinke cares more about helping mining conglomerates than about protecting the BWCA,” McCollum, who is also the top Democrat on the House Appropriations subcommittee overseeing Interior and the Forest Service, said in a statement Thursday. “This decision is yet another part of the Trump agenda to turn our public lands and natural treasures into industrial wastelands for private profit.”

While the Forest Service, a division of the Agriculture Department, is tasked with completing the environmental review, the final say on whether mining should be banned rests with Zinke.

In a fact sheet prepared by the Forest Service, obtained by The Washington Post, the agency said that its decision would not affect Twin Metals Minnesota’s leases — which lie within the area eyed for a withdrawal — because they “are valid existing rights. The Twin Metals lease renewals are a separate issue and the re-issuance of the leases is unaffected by the proposed withdrawal.”

Minnesota Gov. Mark Dayton (D) questioned this interpretation of the law: The Bureau of Land Management typically needs to prove an existing right, even if a lease has been renewed.

“Incredibly, the U.S. Bureau of Land Management now says that Antofagasta’s leases of federal land are to be automatically renewed, which would mean that the company would control the public’s land in perpetuity,” Dayton said in a statement. “I urge the administration to disclose who persuaded it to steamroll responsible review and protection of this priceless natural resource in favor of copper-nickel mining profits.”

Twin Metals Minnesota declined to comment Friday.

Nada Culver, a senior counsel at the Wilderness Society, said there should be “no shortcuts for the Boundary Waters,” arguing that the switch will give the public a diminished voice on mining in Minnesota.

Representatives of the state’s mining industry were encouraged by the move, but pressed the Trump team to rescind the last-minute Obama administration protection outright.

“While this decision is a significant step in the right direction,” Frank Ongaro, executive director of the trade group Mining Minnesota, said in an email, “it still leaves the issue of withdrawal hanging over the region and creates uncertainty for the several companies that have been investing hundreds of millions of dollars into the economy.”