Sunnyside Coal Mine, Carbon County, Utah Carbon Utah USA It was owned by the Utah Fuel Company and began operating in 1897. It was later purchased by Kaiser Steel. According to the Utah Division of Natural Resources, the mine operated the first longwall in the United States. Oral history interviewee Frank Hennes, an engineer at the mine, recalls that the mine had 700 behive coke ovens to process the coal. Miners held dances and social gatherings in a recreation hall. They also had underground wrestling and boxing matches. The mine closed and filed for bankruptcy in 1994. It has since been reclaimed. yes yes