Monterey Coal Company (Monterey) operated the No. 2 Mine in Clinton County, near Albers, Illinois, from April 1977 until August 1996. The operations included coal extraction, coal processing and coal slurry and refuse (mine waste) disposal. The entire No. 2. Mine site occupies approximately 1,400 acres of land, with the waste piles comprising about 300 acres of the total. The No. 2 mine was operated as an underground coal mining facility under permits issued by the Office of Mines and Minerals of the Illinois Department of Natural Resources.