Sharply divergent visions for the future of Minnesota's iconic northland erupted in the crowded final hearing on a proposed copper mine Tuesday, pitting the prospect of lucrative jobs and renewed prosperity against a determination to protect some of the state's most pristine waters.

More than 2,000 people from across the state packed the RiverCentre for the third and final public hearing on the PolyMet Mining Corporation's proposal for a $650 million open pit mine near Babbitt, Minn.

Mine proponents came to St. Paul on buses and in a stream of cars from Ely, Duluth and St. Cloud. They came in hard hats, stocking caps and fluorescent safety vests, sporting "We support mining'' stickers.

Alongside them, in apparently equal numbers, sat opponents of the mining operation. They came with signs and stickers saying "Protect Clean Waters," "Who pays for pollution?" and variations saying no to the planned mine.

"There's no doubt that in 2014 that we can safely extract the minerals without damaging the waters or land. I'm in the tourism industry, and I certainly don't want to shoot myself in the foot," said Joe Baltich, an Ely resort owner and outfitter who was one of hundreds of northern Minnesota residents who traveled south for the hearing.

"But we're losing businesses right and left. We have 360 properties that are for sale, and no one is buying. We lost our Pizza Hut. We're going to lose our schools, our grocery store," Baltich said. "We're going to lose everything, and it's my hometown."

Samantha Chadwick of Minneapolis, who carried her 14-month-old daughter, has heard those economic arguments and the pleas for Twin Cities residents to butt out. "But the Superior National Forest belongs to all of us in this state and the nation," she said. "We need a sustainable economy, but toxic mining isn't sustainable."

"This type of mining is risky, and it's being proposed in the best place in this state — the Lake Superior watershed and near the Boundary Waters," Chadwick said

A more raucous hearing

About 640 people signed up to speak at Tuesday's hearing, but the three-hour session allowed only 59 to take the podium. Although chosen at random, they were nearly evenly divided between those favoring the mine and speakers opposed to the project.

The crowd was more raucous than at earlier hearings, frequently bursting into applause that drew gentle rebukes from the moderator.

Some of those who had signed up to speak surrendered their time to like-minded speakers representing the large labor and environmental groups who have staked out opposing positions on the project.

Before the meeting began, state officials had collected 10,000 comments from e-mails, letters and public hearings that drew about 1,300 people to a session in Duluth and about 650 to a meeting in Aurora. That testimony, as well as stacks of documents and years of study, will factor into the decision by the Minnesota Department of Natural Resources, expected next year, to grant or deny PolyMet the permits it needs.

PolyMet supporters see the promise of 300 to 360 mining jobs and thousands of temporary construction jobs in an area where good-paying work has been vanishing for three decades.

Critics argue that unlike taconite, which has long been mined on the Iron Range, copper-nickel mining presents a new set of environmental risks because the precious metals of hard-rock mining are found in ore that contains sulfites. When exposed to air and water, sulfites can create acid drainage that leaches heavy metals and mercury from rock, polluting nearby waters and threatening aquatic life.

"I know we need jobs," said William Hane of St. Paul. "But there's never been a copper cobalt mine that didn't pollute."

Throughout Tuesday's hearing, however, mine supporters argued that experts had thoroughly analyzed the project.

"This is clean copper mining," said Harry Melander of Mahtomedi, a building and construction trades representative. "No one here wants to do damage to northern Minnesota. Let's not blow a chance to establish globally what good clean copper mining is."

Former state Rep. Tom Rukavina of Virginia also touted the mine's economic benefits, ending his exhortation with a flourish, producing a paper bag and inviting opponents to deposit their cellphones and other electronics that contain the metals PolyMet hopes to mine on the Range.

On cue, other supporters also displayed paper bags.

More questions to come

The St. Paul hearing was the first public forum since state officials announced last week that they may have to redo a major portion of the environmental analysis for the open pit mine, a part on the flow of the nearby Partridge River.

New data indicate that some of the major assumptions used in the analysis may be three times too low, which would throw off many of the conclusions about the mine's potential impact on water.

The 2,200-page environmental analysis, which required five years of study and cost PolyMet about $22 million, was presented late last year. Officials said fixing it could require reworking the complex computer model the environmental analysis was based on, which could take months.

This month's hearings may be just the beginning of a wider debate over resource use and environmental stewardship in northern Minnesota. Many minerals companies besides Canada-based PolyMet are interested in coming to the area, home to one of the world's largest untouched deposits of copper, nickel and other valuable metals.

Mary Lynn Smith • 612-673-4788