NewRange Copper Nickel, the company proposing a mine in Minnesota's Iron Range, says it will re-examine its plans to clean wastewater and store waste rock after courts last year scuttled three major permits.

Representatives of the company presented the new study as an opportunity to refine the overall plan for the NorthMet mine, not a response to the legal losses. But the company's announcement is the first indication NewRange has given in months of where the project is headed.

Environmental advocates were skeptical, though they said they were awaiting more details.

The study will examine four key areas, according to a news release: updating water treatment technologies; storing waste rock, or tailings; reducing the carbon footprint of the project; and boosting efficiency, including potentially increasing the daily output by 25%.

"We actually stand behind the current project and firmly believe it meets standards," said Colin Marsh, NewRange's director of external affairs. He said the project has been undergoing environmental review for many years and that, as time has passed, "we have a new level of expertise" that may make the mine more efficient.

Paula Maccabee, an attorney with the advocacy group WaterLegacy who has repeatedly challenged the project in court, said: "It is too early to know whether they're going to propose fundamental changes, or whether this is a communications effort."

The NorthMet mine project was originally proposed by PolyMet, a subsidiary of the Swiss conglomerate Glencore. Glencore later formed a partnership with the Canadian company Teck, which has its own mine ambitions nearby, and the venture was dubbed NewRange.

NorthMet would extract copper, nickel and other metals from a massive open pit near Babbitt, Minn., and then ship the material for processing at the former LTV Steel site in Hoyt Lakes. Tailings would be stored in an existing basin at the Hoyt Lakes site.

Controlling potential runoff from that leftover rock has been a major point of contention for environmentalists and tribal officials, who convinced an administrative law judge last year that NorthMet's permit to mine should be rejected because its plan to manage tailings was insufficient. The final decision on that permit, however, rests with the Minnesota Department of Natural Resources.

Now, NewRange will study changing the design for the dam that would hold back tailings and the water sitting on top of it, Marsh said. It will also explore whether to hold those tailings in the nearby pits of closed mines, instead of the LTV site.

Kathryn Hoffman, chief executive officer of the Minnesota Center for Environmental Advocacy, said in a statement that the company's announcement "makes this redesign consideration sound like a choice." It's not, she said.

"The courts have been telling them for years that there are fundamental flaws with their proposal that have to be addressed or the plan can't advance," said Hoffman, whose organization has challenged the mine in court.

Copper-nickel mining has been controversial in Minnesota because the sulfide ores where these metals are found have the potential to unleash toxic mine drainage that would damage the environment, including in nearby tribal lands.

The NorthMet mine is the proposal that has advanced the farthest, but in addition to the challenges to its tailings plan, it is waiting on the Minnesota Pollution Control Agency to reconsider a wastewater permit that was thrown out. It also must re-apply entirely for a wetland permit from the U.S. Army Corps of Engineers.

Mining proponents argue the project would provide stable jobs and metals that are needed for the green energy transition.