Mines in the Illinois Portion of the Illinois-Kentucky Fluorspar District
For most of the 20th century, the Illinois-Kentucky Fluorspar District (IKFD) was the primary source of fluorspar for the United States. The strategic importance of flurospar was heightened during World War II because of its use in steel manufacturing. Production of fluorspar ore in this region peaked shortly after World War II, and this peak was sustained until the 1970s, when competition from foreign suppliers began to erode the dominance of this mineral district. Mining continued until the mid-1990s, but with a decline in production.
This report compiles into a cohesive document details of the individual mines within the Illinois portion of the IKFD. Included are sections concerning the mining methods, geology, historical production, and theories of the origin of the ore deposits, as well as maps, exploration reports, drill logs, and production figures scanned fro unpublished mining company files to which the authors were given access. The mine location map that accompanies this circular was designed to augment the Kentucky Geological Survey's 2012 mine map of the Kentucky portion of the IKFD.
Although the last mines in Illinois ceased operations in 1995, there is potential for future mining activities in deeper, relatively unexplored strata. The authors hope this report and the scanned documents will be helpful in future exploration activities and to other interested parties.
Circular 604, Mines in the Illinois Portion of the Illinois-Kentucky Fluorspar District, by F. Brett Denny, W. John Nelson, Jeremy R. Breeden, and Ross C. Lillie, is now available free for download. A print copy can be ordered online for $17.50.