Polymet-ltv
Polymet-ltv is an earth dam located in St. Louis County, Minnesota, built in 1981. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Polymet-ltv
The primary purpose of Polymet-ltv 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 Poly Met Mining, Inc. (private). It impounds the Embarrass River-tr near Embarrass.
The dam stands 69 feet tall and stretches 7,000 feet across, creates a reservoir covering 200 acres, has a maximum storage capacity of 3,000 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1981, the structure is 45 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 10/05/2022.
At 69 feet, this dam is taller than 96% of all dams in the United States.
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Location
| State | Minnesota |
| County | St. Louis |
| Nearest City | Embarrass |
| River/Stream | Embarrass River-tr |
| Coordinates | 47.63194, -92.10233 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 69 ft |
| Dam Height | 65 ft |
| Dam Length | 7,000 ft |
| Year Completed | 1981 (45 years old) |
Storage & Hydraulics
| NID Storage | 3,000 acre-ft |
| Max Storage | 3,000 acre-ft |
| Normal Storage | 800 acre-ft |
| Surface Area | 200 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 50 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Tailings |
| Owner | Poly Met Mining, Inc. |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/05/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN00936 |
| Federal ID | MN00936 |
| More Info | State Dam Safety Program |