Source: Rocks-and-Fossils mailing list 5/23/95
Fluorspar is a primary source of fluorine and fluorine-based compounds. It is used to make refrigeration gases, high performance plastics and coatings, ceramics, and welding rods. It is a fluxing agent for the steel, glass and aluminum industries.
Over much of the year I have had the good fortune of being in contact with many people associated with operations in Hardin County. My family and I enjoyed the opportunity to spend several hours at the home of the manager of one of the mines. Below is a conglomeration of information collected from many sources including the US Forest Service and Eric Livingston, chief geologist for the Ozark-Mahoning Company.
Many of us have seen or own Fluorite cubes, however this type of material is the exception in the mine, not the rule and the typical piece of ore looks like a band of very fine crystals, sometimes only the width of two fingers running across it. Rock containing as little as 15% ore is processed.
Ozark Mahoning is the last surviving domestic producer of high grade fluorspar in the United States. Ninety percent of US consumption is imported, with the remaining 10% coming from Hardin County. Ozark- Mahoning is owned by a parent company, Elf Atochem North American, Inc. The Company came into the district in 1937 and discovered fluorspar deposits north of the town of Cave-In-Rock. Mining and milling facilities were built and official production started in November of 1939. Although there were countless small shafts sunk through out the Shawnee National Forest only three are in operation today. These being the Anna Belle Lee, Denton and the oldest, the Ozark-Mahoning #1 (formerly called the Minerva). Due to the tremendous amount of capital it takes in the modern world to operate such an operation and such things as OSHA regulations, all of these small "mom and pop" mines have ceased operations.
Ozark currently operates three mines and a froth flotation mill which is located in Rosiclare. This means almost all ore is trucked to the central mill instead of being processed on site. All three mines are "deep mines: that are accessed by vertical shafts. Mine #1 was sunk in 1942 and is 680 feet deep. The Denton Mine is 640 feet deep and was put into operation in 1981 while the Anna Belle Lee Mine was brought on line in 1984 at a depth of nearly 1,000 feet. Due to the tilt or dip of the rock units, some places in the mines are 1200 to 1300 feet below the surface.
In the later part of 1993 the company has began going back and mining some of the support pillars in the Anna Belle Lee and Denton Mines. It should be kept in mind that these pillars are being trimmed and not removed. Many of the pillars being worked on are 200 to 300 feet long and as wide as forty feet. Obviously they contain a tremendous amount of material and are essentially being cut into halves and thirds. Four to five miles Northwest of these mines will be the site of yet another mine in the near future. As the company has purchased core drill samples from the past thirty years the new mine will go down to the 2000 foot level into what is envisioned as the "mother lode".
Operations at the two mines will slowly come to an end as employees are needed to install timbers and equipment in the new shaft.
In May of 1994 Ozark-Mahoning signed the papers to purchase the land their new mine will be on. The workers are continuing to back out of the Anna Belle Lee Mine and are presently within 800 feet of the main shaft. Soon only a few workers will remain behind to officially seal the shaft with a concrete cap. The new mine, as yet unnamed, will be dug on the company's recently purchased property instead of the usual locations which is national forest service land.
The mine will sport a main shaft so large that it will be able to have one car going up the shaft while another is descending. A double wide shaft is unusual for the district. The main shaft is to be bored out by a company which specializes in such operations in the western United States. It is estimated to take less than thirty days at an average of 100 feet of solid rock a day in which to bore through. Needless to say, this will be a site worth seeing.
The most important feature of this new mine will be the fact that it will be 2,000 feet deep and is the result of many years of coring drilling and core analysis. The present mines work at approximately the 1,000 foot level. Hopefully this will be the "motherlode" it has been envisioned to be.
Purple Fluorite Crystal
Rocks from Ron Zeilstra's Collection
Index of Specimen Images
Table of Contents