Hecla-day Mine Aspen Tailings Dam

About Hecla-day Mine Aspen Tailings Dam

The primary purpose of Hecla-day Mine Aspen Tailings Dam 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 Hecla Mining Co. (private). It impounds the Tr-granite Creek near Republic.

The dam stands 95 feet tall and stretches 1,050 feet across, creates a reservoir covering 38 acres, has a maximum storage capacity of 625 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.

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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 08/19/2024.

At 95 feet, this dam is taller than 98% of all dams in the United States.

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