Gov. Mark Dayton returned from seeing the environmental aftermath of the Gilt Edge Mine in South Dakota on Tuesday with strengthened resolve to guarantee environmental and financial safeguards for a mine proposed by PolyMet Mining Corp.

Dayton said all contingencies must be prepared for and be backed by company money in case something goes awry.

"If it does proceed, this emphasized the importance of doing it right with safeguards to make sure something like this doesn't happen," Dayton said upon returning. He added that the visit has made him no closer to a decision on the proposed Iron Range copper-nickel mine.

Dayton is visiting two mines this week on the counsel of opponents and supporters of the project to help guide his decision. Gilt Edge, a Superfund site that was once a former gold mine, has cost taxpayers more than $100 million in cleanup and is a model of what PolyMet opponents say could come to Minnesota.

Dayton will visit Michigan's Eagle Mine near Lake Superior on Friday to view what supporters of the Minnesota project say is a far more successful mine.

The PolyMet decision is shaping up to be one of the most important of Dayton's term, a decision that is almost guaranteed to end in lawsuits by whichever group loses, in what has been the company's yearslong, multimillion-dollar effort to win project approval.

Dayton has ex­plic­it­ly said pol­i­tics will play no part in his ad­min­is­tra­tion's de­ci­sion, but he has also not de­nied the deep di­vi­sions the PolyMet is­sue is caus­ing in the DFL coa­li­tion that elect­ed him governor twice.

"There's no middle ground," Dayton said Tuesday when asked about pressure from both sides.

PolyMet's project has drawn intense scrutiny as the company seeks state approval. It would be the first copper-nickel mine in the state, promising a $650 million investment and up to 350 jobs on the site of the now-closed LTV steel mine outside Hoyt Lakes. But critics say the project threatens to bring unacceptable environmental risks that would linger in the state for generations after the mine closes.

PolyMet is the first of what is expected to be several companies lining up to tap one of the world's largest untouched deposits of copper, nickel and other precious metals used for everything from smartphones to hybrid cars.

Dayton is likely to make a final decision on a state permit for the project, in consultation with Department of Natural Resources Commissioner Tom Landwehr, by late 2016, though permitting involves several other state and federal agencies.

State Rep. Tom Anzelc, DFL-Balsam Township, said a decision to stop the PolyMet project would cause a further erosion of economic opportunity on the Range and create a "monumental" fissure between Iron Range Democrats and the more Twin Cities-focused environmental wing of the party.

"I think the overwhelming conversation is, 'Is it the state's policy to write off this region?' " Anzelc said.

The PolyMet per­mit­ting con­tro­ver­sy comes at a sensi­tive time for the Range. Hundreds of layoffs in the tac­o­nite mines of north­east­ern Minnesota have served as a bru­tal ex­cla­ma­tion point on a de­cades-long trend of min­ing ob­so­les­cence, along with a loss of pop­u­la­tion and eco­nom­ic vi­tal­i­ty.

For now, Iron Range DFLers and en­vir­on­ment­al­ists who make up the par­ty's base are giv­ing Dayton some space as he deliberates.

"That this governor is willing to interject himself into this public discussion should not be criticized. To me it's a sign the chief executive of all the people of the state of Minnesota is doing his due diligence," said Anzelc.

Aaron Klemz of Friends of the Boun­dary Wa­ters Wilderness, an op­po­nent of the PolyMet pro­pos­al, said Dayton "has a good re­cord on push­ing for public trans­par­en­cy and in­volve­ment. And, he's made sure his ag­en­cies have re­tained their neu­tral­i­ty."

Still, both sides are mak­ing their case in every avail­able ven­ue.

Rep. Jason Metsa, DFL-Virginia, whose dis­trict has suf­fered more than 1,000 layoffs, said, "This is a com­muni­ty that re­al­ly needs the jobs."

Dayton has said wa­ter qual­i­ty is an is­sue that will help de­fine his place in Minnesota history.

"If he permits a mine that pol­lutes for hun­dreds of years," Klemz said, "we think that would have a very dam­ag­ing ef­fect on his leg­acy."

Klemz and others say this isn't just an issue pitting Twin Cities vs. Iron Range Democrats. They say the entire state, particularly the Range, is displaying a "deep di­vi­sion" over the project.

Patrick Coolican • 651-925-5042