Aggregates Manager Digital Magazine
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by Bill Langer Bill Langer is a consulting research geologist who spent 41 years with the U.S. Geological Survey before starting his own business. He can be reached at Bill_Langer@hotmail.com In Stone A VISIT TO THE Dentist Fluorspar mining endures trials and tribulations that make a geologist wince. Y ou know the drill. I was reclining in the dentist chair while a hygienist jabbed a sharp pick into my gums. She paused and asked: "So you're a geologist. Do you look for gold?" "No," I answered. "I study industrial minerals, like fluorite, which is used to make the fluorine you put on my teeth." I hoped she would continue the dialog and stop jabbing my gums. Besides, I love to talk about fluorspar because it exemplifies the trials and tribulations of industrial mineral development. Fluorspar, like most industrial minerals, has a relatively low value compared with metallic ores mined under similar conditions. The margins of profit are small, and it commonly requires exceptionally good management to profitably conduct any fluorspar (or most other industrial mineral) mining operation. During the late 1800s, fluorspar was used chiefly in the manufacture of opalescent glass and the preparation of fluoride-bearing chemical compounds. However, in the early 1900s, the use of fluorspar increased when it replaced some of the limestone as a flux in the manufacture of open-hearth steel. Most steel production was located in the contiguous states of Pennsylvania, Ohio, Indiana, and Illinois. Fluorspar deposits in Illinois and Kentucky that were near those markets and were accessible to water or rail transportation had a huge advantage over those not so favorably situated. So, while there is high-grade fluorspar in many western states, during the early 1900s, their development was handicapped by the costs of long transport. The quantity of fluorspar in a deposit is critical. During the early 1900s, a commercial deAlthough the last U.S. fluorite mine closed in 1995, posit needed to produce at least a railcar load of marketable fluorspar a day and have at least mining is expected to resume in Kentucky. a 15-year life. Unscrupulous promoters swindled prospective producers out of large sums of money for the purchase of leases on properties that did not contain fluorspar in sufficient quantity to warrant development. Fluorspar may contain impurities that have to be eliminated for many uses. A log washer commonly was used to clean fluorspar, and a convenient supply of water was essential. In arid portions of the West, fluorspar was cleaned by hand cobbing, which entailed much manpower and large amounts of waste. This further reduced the competiveness of western fluorspar operations. During the second quarter of the 19th century, the production of steel continued to drive the fluorspar market, but new applications continued to be developed, including CFC (Freon) used in refrigerators and air conditioners. Meanwhile, cheaper imports replaced U.S. production, and, by mid-century, over a quarter of the fluorspar used in the United States was imported. During the third quarter of the 20th century, the markets for fluorspar exploded. Fluorine found its way into applications including aerosols, anesthesia, plastics, rubber, satellites, Teflon, and toothpaste. The list of uses kept getting longer and longer. During 1974, the demand for fluorspar peaked, but 88 percent of the demand was met by imports. During the last quarter of the 20th century, fluorspar's use in steelmaking decreased dramatically, and the production of CFC was stopped because of its impact on the ozone. The last U.S. fluorite mine closed in 1995, signaling the end of 158 years of U.S. fluorite mining. Today, we are totally dependent on imports of fluorspar, a mineral which once was deemed vital to the nation for security and economic reasons. The good news...mining is expected to begin again in Kentucky. Did I tell you the hygienist's response to my mention of fluorspar? Jab, jab, jab! If only I had studied gold. 40 AGGREGATES MANAGER October 2013 Carved_AGRM1013.indd 40 9/18/13 3:19 PM