Contractors have started to build a permanent water outlet structure that will help manage water levels at the Canisteo Mine Pit in Itasca County. When it's finished, this new structure will channel water into the Prairie River, which means that water levels will be managed year-round without the need for seasonal pumping.
The DNR isn’t planning to open public access at the Canisteo, and construction will limit recreation around the mine pit. As construction is underway, workers may be using public roads to access the Canisteo and nearby construction sites. If you are in the areas of Coleraine, Bovey, or Taconite and enjoy being outdoors, please keep an eye out for safety signs and construction activities. And ensure you have permission from landowners if you plan to explore areas around the Canisteo.
Watch this video about the outlet construction and why this project is a huge achievement in managing Canisteo’s water levels.
Brief overview
The Canisteo Mine Pit (Canisteo) is formed by a complex of inactive iron ore mine pits that have filled with water. Located in Itasca County, Minnesota, the Canisteo is north of the cities of Coleraine, Bovey, and Taconite.
Traditional iron ore mining began in the Canisteo in 1907 and continued through 1980. Mineland Reclamation Rules for ferrous mining were adopted in 1980, requiring mining operations to plan for closure and reclamation. Between 1980 and 1986, mining in the Canisteo consisted exclusively of scram operations. Reclamation was only required for disturbances connected to scram mining operations and not water level management. Therefore, the Canisteo is considered a legacy mine pit and no company is responsible for managing water levels.
The DNR's role in managing water at a pre-1981 site like the Canisteo Legacy Mine Pit, similar to numerous other water challenges across the state, is to provide technical expertise for and regulatory oversight of any water appropriation or work in public waters in accordance with Minnesota Statute 103G.
As water levels rose within the Canisteo, the full extent of potential hydrologic impacts to surrounding communities was unknown. To address this, the DNR began monitoring for pit water level and surrounding groundwater changes in 1990 in order to create an important data record from which water level predictions could be made.
An engineered outlet structure is under construction. When it is complete in the summer of 2025, the outlet will control the pit’s water levels year-round to ensure the neighboring communities are not adversely affected. As of March 2025, the Canisteo water level is around 1305 feet, which is 19 feet below natural overflow. Without a permanent outlet, the DNR estimates water would rise at a slow rate, and the pit would naturally overtop. Any runout would be a trickle amount at the lowest elevation of the pit rim at 1,324 feet, which would not pose an imminent threat to public safety and would allow time for the DNR to address the issue.
The DNR and Iron Range Resources & Rehabilitation have been and will continue working with local communities to implement a long-term solution. Legislative funding is now available for construction and operation of an engineered outflow.
Canisteo water level management
After iron ore mining and subsequent pit dewatering ended, the Canisteo began to fill with water from precipitation and both surface water and groundwater inflow. The increasing pit water level created concerns within nearby communities, including a rising water table within the city of Bovey. In response to these concerns, the DNR conducted various studies to evaluate potential impacts from the rising pit water level.
The results of these studies indicated the effects from an already high water table in city of Bovey were worsened by the rising water level in the Canisteo. Groundwater flowed from the pit lake through subsurface materials toward the city. In 2011, the DNR designed and constructed a drain tile system along 1st street. The drain tile system diverts groundwater away from residential structures located within the city.
In 2012, the DNR issued a water appropriation permit to Magnetation LLC, a scram mining operation, authorizing the pumping of water from the Canisteo for mining operations. This pumping resulted in a decrease in the water level until Magnetation LLC filed for bankruptcy in 2015. Pumping ceased in 2016, resulting in a rising pit water level.
ERP Iron Ore LLC acquired Magnetation LLC assets and resumed intermittent pumping in 2017. Pumping again ceased in 2018 when ERP Iron Ore LLC entered bankruptcy, and the water level in the pit began rising again.
Water level monitoring
The DNR Lands and Minerals Division actively monitors the Canisteo water level and surrounding groundwater levels to understand the rate of pit water level increase and groundwater flow through the subsurface materials. Hydrologic information gathered near the pit informs the assessment of the need for an engineered outlet structure to prevent future flooding and other impacts. The city of Bovey drain tile system is monitored for flow and system efficiency. The Canisteo water level trend shown above represents a combination of manual measurements (dashed line) and continuous logger measurements (solid line).
As of March 26, 2025, the Canisteo water level is around 1,305 feet, which is 19 feet below natural overflow. Two natural overflow locations at elevation 1,324 feet have been identified along the pit rim, one of which is located north of the city of Bovey. Groundwater level monitoring indicates groundwater outflow from the pit moves to the south. The current hydrologic conditions in nearby communities demonstrate the need to design and construct an engineered outlet for the Canisteo.
The 2023 Minnesota Legislature approved $8.875 million in bonding funds to construct an outlet at Canisteo. The DNR has a contract in place, and construction of a permanent outlet structure is underway to manage Canisteo's water levels.
Water rises in the pit naturally due to rainfall, snow melt, and groundwater. The DNR will continue to manage water levels, if necessary, until the permanent outlet is constructed.
Permanent engineered outlet construction
Contingency pumping at the Canisteo was a short-term solution to manage water levels until a permanent outlet is constructed. In 2023, the Minnesota legislature approved $8.875 million dollars for the construction of an outlet at the Canisteo. Construction on the permanent water outlet structure is underway and is expected to be completed in August 2025.
Once the outlet is completed, water from the Canisteo will flow into the Prairie River. The permanent water outlet will provide year-round water level management, eliminating the need for seasonal pumping.
Photos of the permanent outlet construction
The Canisteo Legacy Mine Pit (Canisteo) is a mine pit formed in a complex of several inactive iron ore mine pits including the Lind Pit and the West Hill Pit in Itasca County north of the cities of Coleraine, Bovey, and Taconite.
2025: Construction started this winter with tree removal and land clearing along the entire outlet path.
2025: Construction on the Canisteo Outlet began this winter, starting with moving a stockpile and clearing the land.
Old culverts have been replaced with new, properly sized culverts at the Lind Pit along the outlet route.
Construction crews have been ditching and installing culverts.
Starting in the west and progressing east through the wetland areas, construction crews have been ditching and installing culverts.
Once the outlet is completed, water from the Canisteo will flow into the Prairie River.
Once the outlet is completed, water from the Canisteo will flow into the Prairie River.
Ariel map showing the outlet point from the Canisteo Legacy Mine Pit through the Lind and West Hill Mine Pits and discharged into the Prairie River
Contact
DNR Lands and Minerals Division
St. Paul, MN
651-259-5689