sentences:  Kennecott Minerals operated the Ridgeway open-pit gold mine from 1988 to 1999, and the land is now being reclaimed by Kennecott.The Barite Hill mine operated from 1990 to 1994.The only operating gold mine in South Dakota is the Wharf mine, at Lead, an open pit heap leach operation operated by Coeur Mining that produced 109,000 ounces of gold in 2016.