ABSTRACT
Large-scale mining for bentonite in the Northern Great Plains of the United States began in the 1930s; however, only limited reclamation was achieved prior to the passage of state reclamation laws in the early 1970s. The Northern Great Plains states of Montana, South Dakota, and Wyoming produce 90% of the nation’s supply of bentonite (Ampian, 1980). In 1973, more land was disturbed by bentonite mining than coal mining in Montana and more abandoned mine spoils had accumulated over the years from bentonite mining than from coal (National Academy of Sciences, 1974). This example is indicative of the Northern Great Plains in general.
