Republic Mine Tailings Pond Dam B Reservoir Report

Last Updated: December 22, 2025

Republic Mine Tailings Pond Dam B, located in Republic, Michigan, is a privately owned earth dam that serves the primary purpose of storing tailings.


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Summary

Completed in 1960, this dam stands at a height of 42 feet and has a length of 12,320 feet, with a storage capacity of 5,000 acre-feet. The dam is regulated by the Michigan DEGLE and undergoes regular inspections, with a low hazard potential rating and a very high risk assessment due to its proximity to a tributary of the Michigamme River.

Despite its low hazard potential, Republic Mine Tailings Pond Dam B poses a high risk due to its age and location, with the potential for significant environmental impact in the event of a failure. The dam's controlled spillway, with a width of 49 feet, helps manage water levels and reduce the risk of overtopping during heavy rainfall or snowmelt. The dam has not been rated for its condition assessment, highlighting the need for continued monitoring and maintenance to ensure its long-term stability and safety for the surrounding community and ecosystem.

While the dam currently meets regulatory guidelines and has not experienced any significant modifications or incidents, the lack of a formal Emergency Action Plan (EAP) and updated risk management measures raises concerns about its preparedness for potential emergencies. With its high risk assessment and the potential for severe consequences in the event of a failure, ongoing attention to maintenance, monitoring, and emergency preparedness is crucial to mitigate risks and protect water resources and the environment downstream.

Year Completed

1960

Dam Length

12320

Dam Height

42

River Or Stream

Tributary to Michigamme River

Primary Dam Type

Earth

Surface Area

288

Hydraulic Height

42

Nid Storage

5000

Structural Height

42

Hazard Potential

Low

Nid Height

42
       
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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.