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Q: What is the PolyMet mining project?

A: PolyMet, a Minnesota-based mine development company, has proposed a project called NorthMet to mine copper, nickel and other metals, with an associated processing plant, near the city of Hoyt Lakes. The site, in the St. Louis River watershed about 175 miles upstream from Lake Superior, is an old LTV Steel taconite and steel processing facility.

Q: What does Gov. Mark Dayton's approval of the project mean?

A: To some extent it's merely symbolic — he can't single-handedly approve the project, and Dayton has said he wants agencies to independently review permit applications. But he had various levers to kill the project if he had opposed it, and his support eliminates that possibility while offering strong political cover to his agencies if they wind up permitting it. The Department of Natural Resources is expected to release a draft permit-to-mine by the end of the year, perhaps even sooner.

Q: Then what happens?

A: There will be a minimum 52-day public comment period once the draft permit has been released, to be followed by a final permit decision.

Q: And then the company can begin operations?

A: No. There are many other permits the company must obtain from the DNR. They include approval for a wetland replacement plan, water appropriation, dam safety, burning, taking endangered species and work in public waters.

Q: Is that it?

A: No. The Minnesota Pollution Control Agency is considering permits on air and water quality, with water quality assurance a necessary ingredient of another permit for disturbing wetlands from the U.S. Army Corps of Engineers.

Q: How many jobs would the project create?

A: The company says the project would employ 360 full-time workers, plus another 600 indirectly.

Q: How much would the mine produce?

A: PolyMet says the mine annually would yield 72 million pounds of copper, 15.4 million pounds of nickel, 720,000 pounds of cobalt, plus other precious metals. The metals are used in countless household objects and technology.

Q: What do environmentalists fear about the project?

A: They have several concerns, including the risk that toxic tailings would pollute the St. Louis River watershed and Lake Superior, which contains 10 percent of the world's fresh surface water. They're also worried that water from the open-pit mine and metal processing sites would have to be treated for decades after the mine closes, at a cost of millions of dollars.

J. Patrick Coolican