PolyMet Mining’s NorthMet Project is part of northeastern Minnesota’s Duluth Complex, one of the world’s largest known undeveloped deposits of copper, nickel and other precious metals. The project would be the first in Minnesota to commercially extract metals from the Duluth Complex. Download an overview of the PolyMet project land exchange [PDF] from the Minnesota Department of Natural Resources.

Project location

The project is located near the community of Hoyt Lakes, within an existing mining district where operating and former iron mines and processing facilities dot the landscape. Here, mining is woven into everyday life, supporting generations of workers and their families and building the communities in which they live. PolyMet, which controls 100 percent of the NorthMet ore body through long-term mineral leases, plans to build an open-pit mine to recover these critical metals using modern mining and processing methods.

Robust economics

All stakeholders stand to benefit from the economics of the PolyMet project. When fully operational, the mine and processing facilities will have a significant economic effect. It will employ approximately 360 people, and according to an independent study [PDF] by the University of Minnesota Duluth Labovitz School of Business and Economics, the PolyMet Mining project will generate an estimated $515 million in wages, benefits and spending for St. Louis County. Thats a benefit of $1.4 million daily or more than $10 billion over the 20-year permit. In addition, the project will create an estimated $15 million annually in state and local tax revenues, $45 million annually in federal tax revenue, and offer investors an internal rate of return (IRR) of approximately 30 percent. More than $200 million has been invested in the project since 2006, dollars that have been primarily spent in Minnesota toward wages and consulting fees, environmental studies, land acquisitions and leases, engineering and other work.


PolyMet’s NorthMet Project will annually produce 72 million pounds of copper, 15.4 million pounds of nickel, 720,000 pounds of cobalt and 106,000 troy ounces of precious metals.

Environmental commitment

The mine and processing facilities will comply with all applicable state and federal standards designed to protect Minnesota’s water, air, and other natural resources at the project site, which is 175 river miles upstream from Lake Superior. The plant and mine site are not in the Rainy River Watershed that includes the Boundary Waters Canoe Area Wilderness (BWCAW).

The Duluth Complex

The Duluth Complex, a geological formation near the Mesabi Iron Range, contains one of the world’s largest known undeveloped accumulations of copper-nickel-platinum-group-metals (PGMs). Shaped something like a folded taco shell, the massive Duluth Complex’s southwestern-most edge starts just south of the City of Duluth, extends north toward Hoyt Lakes and then arcs northeast into Canada toward Thunder Bay, Ont. The NorthMet deposit and the bulk of the known copper-nickel-platinum-group-metals in the complex are found along the northern margin of the complex in a region running about 30 miles between the cities of Babbitt and Ely, Minn., and just south of the eastern end of the Mesabi Iron Range. The Iron Range has been a major iron ore source of the domestic steel industry dating back to 1880.


Located in the Partridge River Intrusion of the Duluth Complex, the NorthMet deposit is a large tonnage disseminated sulfide deposit in heterogeneous troctolitic rocks associated with the 1.1 billion-year-old Mid-Continent Rift. It contains copper, nickel, cobalt, platinum, palladium, gold and silver. The majority of the metals are concentrated in, or associated with, four metallic minerals: chalcopyrite, cubanite, pentlandite and pyrrhotite.

PolyMet Mining’s NorthMet Project

The project features two significant assets, the deposit itself and the former Erie processing facilities and infrastructure that together cover approximately 16,700 contiguous acres, or about 26 square miles. The company is seeking permits to operate the mine and processing facilities for 20 years at a mining rate of 32,000 tons of ore per day.

Land exchange

Because the ore body is located beneath U.S. Forest Service land, the company has proposed a land exchange that would give the company surface ownership of approximately 6,650 acres of federal land in exchange for approximately 6,720 acres of private land held by PolyMet – properties that fit into the goals of the Forest Services forest management plan. Download the DNR’s fact sheet on the PolyMet land exchange [PDF].

The NorthMet deposit

Our NorthMet ore body is near a number of closed iron ore mines and the operational Peter Mitchell open-pit mine immediately north. The ore body comprises 275 million tons of proven and probable reserves grading 0.79 percent copper equivalent with Measured and Indicated Mineral Resources of 694 million tons grading 0.74 percent copper equivalent. Please refer to the Updated Technical Report [PDF] for assumptions and explanations.

The mine being permitted will consist primarily of three open pits: the West Pit, which will occupy about 320 acres and reach a depth of about 700 feet, the East Pit, which will occupy about 150 acres and extend to a depth of about 630 feet, and the much smaller Central Pit, which will occupy about 50 acres and reach a depth of 350 feet. Mining will start in the East Pit and soon be followed by mining in the West Pit. The adjacent pits will be mined simultaneously until the East Pit is mined out and subsequently backfilled. In total, the mine will be about 2.5 miles long and a half-mile wide.

Processing facilities

Ore from the mine will be transported by rail approximately six miles west to processing facilities located at the LTV site, a former taconite processing facility that was idled in 2001, optioned by PolyMet in 2003 and purchased by the company in 2005.

LTV mining site

Facilities at the former LTV site (pictured above) will be refurbished and upgraded to modern standards. The site includes crushing and milling facilities, electric substations, tailings facilities, maintenance shops, an office building, railroad and other essential infrastructure.

Though the plant previously processed up to 100,000 tons of ore per day, the PolyMet project is currently designed to process 32,000 tons of ore per day, using less than one third of the plant’s capacity. Working in an established mining district and reusing the existing infrastructure reduces development costs and new disturbances to the environment. Refurbishment of the mill and associated infrastructure is effectively Minnesota’s largest recycling project. See the current Environmental Review and Permitting Status.