In the late 19th century and early 20th century, most coal mining operations focused on underground mining. With the success of Jellico coal, Campbell County became the largest coal producer of any county in Tennessee, producing over one million tons (appx. 900,000 metric tons) per year between 1912 and 1924. By the 1940s and 1950s, however, surface mining had become the mining companies' preferred coal extraction method. During this period, the Saxton Coal Company operated a large surface mine at what is now Indian Mountain State Park. In 1960, after the mine's coal resources had been exhausted and the mine abandoned, the City of Jellico obtained ownership of the mine and with the help of several state and federal agencies, began restoring the denuded, unattractive land. Indian Mountain State Park opened in 1971.