REDWOOD FALLS, Minn. -- DFL Gov. Mark Dayton on Thursday called his Republican rivals "highly irresponsible" for pledging to re-open an Iron Range mine before an environmental study is done.

Republicans are "just pandering to people up there," Dayton told reporters. "They're like a lot of other hucksters who have gone up there saying they have jobs to offer, so vote for us."

Dayton, who is seeking re-election, said he will wait until after an environmental impact assessment is completed before he takes a stand.

"I think that's the responsibility I have as governor," Dayton said before giving a short address at the annual FarmFest trade show here.

Earlier this week, Dayton's GOP rivals said they would give a green light to the PolyMet mine being planned near Hoyt Lakes.

The controversial, $650 million proposal would reopen the abandoned LTV steel facility there, but use it to mine the Duluth Complex, one of the world's largest undeveloped deposits of copper, nickel and precious metals.

The project has raised the ire of environmentalists, who say the project could degrade ecologically fragile lands and result in long-lasting pollution of nearby rivers and even Lake Superior.

The mine is projected to create 360 jobs. An environmental study by the state Department of Natural Resources is underway, with a report due later this year

Dayton's remarks come less than a week before a primary that will determine which candidate Republicans will choose to face Dayton in the November election.