Northshore Mining is an earth dam located in Lake County, Minnesota, built in 1977. It carries a High hazard potential classification.
Dam profile
NID height · 100 ft100 ft tall and 26,000 ft long, taller than 98% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Northshore Mining
The primary purpose of Northshore Mining is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by Cliff-erie (private). It impounds the Beaver R-tr Os near Silver Bay.
The dam stands 100 feet tall and stretches 26,000 feet across, creates a reservoir covering 1,575 acres, has a maximum storage capacity of 31,500 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1977, the structure is 49 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 10/08/2024.
At 100 feet, this dam is taller than 98% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Minnesota dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Minnesota |
| County | Lake |
| Nearest City | Silver Bay |
| River/Stream | Beaver R-tr Os |
| Coordinates | 47.27508, -91.36606 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 100 ft |
| Dam Length | 26,000 ft |
| Year Completed | 1977 (49 years old) |
Storage & Hydraulics
| NID Storage | 31,500 acre-ft |
| Max Storage | 31,500 acre-ft |
| Normal Storage | 15,750 acre-ft |
| Surface Area | 1,575 acres |
| Drainage Area | 3 sq mi |
Ownership & Safety
| Purpose | Tailings |
| Owner | Cliff-erie |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 10/08/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MN01477 |
| Federal ID | MN01477 |
| More Info | State Dam Safety Program |