The Bruno Creek Tailings Impoundment is a

tailings dam A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and potent ...

on Bruno Creek, southwest of Challis in Custer County,

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

. It serves to store

tailings In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overlie ...

for the nearby

Thompson Creek Mine The Thompson Creek mine is one of the largest molybdenum mines in the United States. The mine is located in northern United States in Idaho. The Thompson Creek mine has reserves amounting to 205 million tonnes of molybdenum ore grading 0.06% molyb ...

. At tall, it is the second tallest center-line tailings dam in the world. In 2008, Phase 8 of the mine was approved which includes a raising of the dam to . The dam is mainly composed of cycloned sand. Currently, the dam stores of tailings and the raise would increase storage to . The downstream slope of the dam will be steepened from 3:1 to 2.75:1. In 1994, it was discovered that

acid mine drainage Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines or coal mines. Acid rock drainage occurs naturally within some environments as part of the rock weathering ...

had been forming on the embankment since 1987. Since seepage does occur at the dam, a system of wells was installed to monitor groundwater and a seepage return dam was constructed downstream.

References

{{reflist Dams in Idaho Tailings dams Buildings and structures in Custer County, Idaho Dams completed in 1983 Mining in Idaho