PolyMet Mining Co. achieved another landmark in its efforts to build the first copper-nickel mine in Minnesota when it submitted the first three permit applications for the proposed mine near Hoyt Lakes.

The company submitted a water appropriations permit to the Minnesota Department of Natural Resources (DNR), a water pollutant discharge permit to the Minnesota Pollution Control Agency and a tailings basin dam safety permit to the DNR.

In all, the company will be required to submit nearly two dozen permits, the most crucial of which will be the “permit to mine.” That permit, to the DNR, will lay out how the company can proceed with unearthing the mine, moving and processing the ore and dealing with any polluted water at the site. That permit also will dictate how much money PolyMet will be required to set aside as an insurance policy should any problems occur.

The Duluth News Tribune reported that the company hopes to have all the permits approved and work started in 2017, along with securing financing to pay for the project, and then start mining about 18 months after construction begins.

The applications are “another important milestone for PolyMet and the NorthMet Project,” said Jon Cherry, PolyMet president and chief executive officer, “We recognize that water is one of Minnesota’s most valuable resources and we have taken extra time and effort to ensure that our permit applications detail the ways in which we will protect this resource and meet the various regulatory standards required for Minnesota’s first copper-nickel mine.”

The permit applications come after the March decision by Minnesota Department of Natural Resources Commissioner Tom Landwehr that his agency's decade-long environmental review of the proposed PolyMet copper mine project was legally "adequate."

That decision signaled a transition away from environmental review and toward developing details of how the state's first copper mine might be built and operate, although it’s still possible that the state and PolyMet could hit a snag on details of a permit that could unravel the project.

The final environmental review report concluded that PolyMet operations will not raise downstream sulfate levels or harm wild rice, won't send tainted ground water north toward the Boundary Waters Canoe Area Wilderness as some critics have suggested and will not violate downstream mercury limits in the St. Louis River watershed.

The DNR concluded that PolyMet could operate within all current state and federal pollution standards — that the project won’t have impacts but that those impacts will be small or manageable.

PolyMet is proposing an open-pit copper mine, with processing at the former LTV Steel Mining Co. taconite plant. The project, estimated at $650 million to build, would employ about 300 workers for about 20 years.

Supporters say the jobs would help diversify the Iron Range economy that is tied to the cyclical iron ore mining industry.

PolyMet still needs to raise an estimated $650 million to "build out" the mine and refurbish the processing center to begin production.

PolyMet also will have to buy some sort of bond or insurance policy to cover the estimated $200 million needed to cover any mishaps at the mine — and also to rehabilitate the site after mining ends — plus another $3 million to $6 million annually to cover water treatment at the site that may have to continue decades after the mine is played out.