Lucky Friday No 4

About Lucky Friday No 4

The primary purpose of Lucky Friday No 4 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 private-owned. It impounds the Little North Fork South Fork Coeur D Alene River South Fork Coeur D Alene River near Mullan.

The dam stands 132 feet tall and stretches 2,070 feet across, creates a reservoir covering 16 acres, has a storage capacity of 624 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2010, the structure is relatively new.

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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 07/30/2020.

At 132 feet, this dam is taller than 99% 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 Idaho 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.