News release: Winter contingency pumping at Canisteo Mine Pit may cause unsafe ice conditions

December 30, 2022

The Minnesota Department of Natural Resources has begun contingency pumping at the Canisteo Legacy Mine Pit to keep water levels below 1,318 feet for the protection of local community infrastructure.

The pumping will cause Canisteo water levels to drop, creating a gap between winter ice cover and the unfrozen water surface, resulting in unsafe ice conditions across the entire pit.

Water from the Canisteo is flowing into nearby wetlands and Holman Lake in Itasca County, potentially causing unsafe ice conditions on those waterbodies as well. The DNR strongly advises that people and recreational vehicles stay off the ice this winter at the Canisteo, nearby wetlands, and Holman Lake.

Winter pumping at the Canisteo Pit will ensure the drain tile system in the city of Bovey will continue to divert groundwater away from residential structures. The pumping system is located on the east side of the Canisteo and is drawing water from the pit at a maximum rate of 11,000 gallons per minute. The water is being discharged to a wetland complex that flows into Holman Lake.

Additional information

Mining in the Canisteo stopped in 1980 and there is no company responsible for managing the Canisteo’s rising water levels. As of December 2022, the Canisteo’s water level was at approximately 1,311 ft., 13 feet below natural overflow levels.

The DNR planned to begin pumping the Canisteo on Oct. 1 but deferred this when DNR invasive species specialists discovered zebra mussels in the pit water in September. To prevent the spread of invasive species downstream, the DNR must ensure that zebra mussel larvae, called veligers, are not present in the Canisteo before water is discharged into surrounding waterbodies. Veligers drop out of the water column when water temperatures are below 53 degrees, so the DNR is pumping in the winter to prevent zebra mussel spread.

With $710,000 dollars from the Department of Iron Range Resources & Rehabilitation, contingency pumping at the Canisteo is a short-term solution to prevent water from overtopping the pit. A permanent solution will require legislative funding. The DNR is working with state agencies, local governments, and private entities to plan the permanent engineered outlet project. Once legislative funds are available, construction of the outlet structure will take an estimated one year to complete. More information is available on the Canisteo Mine Pit page of the DNR website.

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