Minntac Tailings Reservoir Report

Last Updated: December 5, 2025

Minntac Tailings, located in St.


°F

°F

mph

Wind

%

Humidity

Summary

Louis County, Minnesota, is a crucial component of the mining industry in the region. Completed in 1978, this Earth-type dam stands at a height of 50 feet and spans an impressive length of 63,360 feet. With a storage capacity of 143,000 acre-feet, it serves as a repository for tailings from mining operations, essential for environmental management and sustainability.

Owned privately and regulated by the Minnesota Department of Natural Resources, Minntac Tailings plays a vital role in the closed system of the region, ensuring safe disposal of mining byproducts. With low hazard potential and a satisfactory condition assessment as of 2013, the dam has been subject to regular inspections to maintain its integrity and safety standards. In the event of any emergency, the dam operators are well-prepared to handle any potential risks, keeping local residents and the environment protected.

Despite being a man-made structure, Minntac Tailings seamlessly integrates with the natural landscape, showcasing the importance of responsible water resource management in the context of mining activities. With its efficient design and operational protocols, the dam stands as a testament to the industry's commitment to environmental stewardship and sustainability. Climate enthusiasts and water resource advocates can appreciate the intricate balance between resource extraction and conservation embodied by Minntac Tailings, setting a standard for responsible practices in the mining sector.

Year Completed

1978

Dam Length

63360

Dam Height

50

River Or Stream

CLOSED SYSTEM-OS

Primary Dam Type

Earth

Drainage Area

13.3

Nid Storage

143000

Structural Height

50

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

50
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.