The permit covers 3,605 acres of underground mining and 848 acres of surface support area for the mine, to be located about 7 miles west-northwest of Pinckneyville. Lost Prairie will be a continuous miner operation—up to five CMs may be used—extracting coal from the Herrin No. 6 seam, a predominant seam in the Midwestern state.

Lost Prairie will be a significant producer, with an expected output of approximately 800,000 tons during its first year of operation, then ramping up to about 3.5 million tons annually. Exactly when that will be is a bit uncertain. The new mine could face competition from the three low-cost Cline longwall mines and the longwall mine White Oak is developing in Hamilton County with financial support from Alliance Resource Partners.

Lost Prairie represents a reunion of sorts between Arch and southern Illinois, particularly Perry County. Once, Arch was synonymous with mining in the county and its Captain surface mine was one of the largest mines in the region.