The Canisteo Pit is essentially a 1,400 acre lake in eastern Itasca County. It formed from groundwater seepage into abandoned mine pits.
Canisteo's remarkably clear water is some 300 feet deep. The pit has been stocked with trout and it is popular with area anglers. It's also within easy reach of Excelsior Energy's proposed coal gasification power plant near the town of Taconite.
That plant, known as the Mesaba Energy Project, will need plenty of water for its cooling towers. Dr. Ed Anderson lives south of the proposed power plant. Anderson is worried about Excelsior's plans to draw water from the Canisteo pit.
"What they plan to do is just put the water through their cooling towers and put it directly back into the Canisteo Lake," Anderson says.
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But 80 percent of the water will be lost to evaporation, meaning the remaining 20 percent will carry, per volume, a much richer load of minerals. Anderson says the water that returns to the pit will slowly push up the entire pit's mineral load.
"And that will increase mercury. It will increase sulfates, and it will increase total hardness a lot," Anderson says.
Anderson says documents filed by Excelsior Energy show they foresee the possibility of that happening to the Canisteo Pit.
"They say that over the course of 30 years, it will be at a critical mass such that they can't use it potentially in the plant anymore, and can't discharge it anymore," Anderson says. "And their plan is to address it at that time."
And Anderson worries that the mineral problem won't just stay in the pit. There are plans to drain excess water from Canisteo into another popular lake to the south, Trout Lake. That's because Canisteo's water levels are constantly rising, threatening to flood the nearby towns of Bovey and Coleraine. Power plant developers say they can draw down the pit by using the water.
Also, Canisteo's clean water is supposed to help reduce phosphorus now in Trout Lake - unless, of course, Canisteo develops a pollution problem of its own.
But that's not going to happen, according to Tom Micheletti, Co-President of Excelsior Energy.
Micheletti says mineralization might never happen in the spring-fed pit. And if there is a problem, he says, it can be fixed.
"We have things that we can do to deal with, to the extent that that certain constituents in the water do concentrate up in the pits, 25 or 30 years out," says Micheletti. "There are things, steps, that we can take to eliminate that problem."
The predicted mineralization is reminiscent of a problem at the Minntac Taconite plant near Mountain Iron. Minntac reused pit water in its pellet making processes, until the minerals in the water were so rich they were damaging equipment.
But, according to Micheletti, Minntac didn't see the problem coming, while his power company does.
"And it's a difficult thing to do if you haven't planned ahead,"says Micheletti. "And we're planning ahead, because we know this is a 40 or 50 year facility, and that we need to think through how we'll handle that."
The Minnesota Department of Commerce holds public meetings on the Iron Range this week, to hear about which environmental issues should be addressed in an Environmental Impact Statement. It will consider things like water quality, air emissions and wetland mitigations. Project Manager Bill Storm, with the Department of Commerce, says these kind of meetings do make a difference in a project's final documents.
"There can be things that are brought up in these public meetings that we weren't aware of, or needs that the local public has concerns about, that we can consider as we move through the process, especially as we get to writing the site permit," says Storm.
Excelsior Energy's draft Environmental Impact Statement is expected late this year.