Idaho's Silver Valley has produced more than 1.2 billion ounces of silver from what were once hundreds of actively worked mines, though only a few active operations remain today. The impoundment there stores tailings from Hecla's Lucky Friday Mine, the fine grained rock left after valuable silver, lead, and zinc minerals have been removed. This synthetically lined, earthen fill dam will store 2.64 million tons of tailings, and when complete the area will be covered and planted with native grasses and shrubs.