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1920-1929 Castlegate mine blast in Utah that killed 171 men, Coal Age published feature on the British practice of "Stone Dusting." Leeds University professor J. A. S. Ritson clamed that stone dusting was largely responsible for a British fatality rate 1/3 as large as the U.S. "Soon after the erection in 1908 of an experiment station at Altofts, England…two facts were thoroughly demonstrated. They were: That coal dust might form an explosive mixture with air and that fine stone dust acts as a barrier to the spread or propagation of a coal-dust explosion." In the six page feature, Ritson presents scientific evidence of his thesis and offers solutions as well examples of methods to spread the rock dust. In the same issue, Coal Age reported that shale dusting was spreading rapidly in Illinois. As part of an interview with J.E. Jones, safety engineer at Old Ben Coal Corp., who has "more experience in rock dusting than any man in this country," the magazine reported that the new tech- nology's adoption was largely due to a tour by members of the British Mines Department had made through the region. Spurred on by the deaths of more than 400 men from explosions beginning January 1, virtually all of the large mines in southern Illinois were adopting the new technology. Old Ben at the time had start- ed applying "shale dust in its mines in four ways: in concentrated barriers con- taining one and a half to three tons of dust, in V-shaped troughs, piled on plat- forms elevated a few feet from the floor and spread on roof and ribs. It is roof- and-rib dusting which is now being intro- duced into many of the large mines of southern Illinois." To spread the shale dust, a new device, the traveling blower, was developed. To pulverize the dust to a fineness of 250-mesh was also difficult, as was figuring out the best mixture of dust to suppress explosions. Each day they got it wrong, the chemists and technicians who were working at these mines feared could bring news of another preventable disaster. By May of that year, Mr. Jones was able to boast that between all the mines of Franklin County, the protec- tion against explosion had been extended to a point where 4,350 of the 12,855 under- ground men…are protected with shale dust and 1,925 with enclosed lights." Franklin County's gassy coalfields were quickly expanding. And as it did, so did the amount of fatalities. From 1904-1921 deaths there were "nearly double that of the state for the same period. The difference in the rate was largely due to the fatalities which were the result of mine explosions. The number fatalities in Franklin county mines from all causes during this eighteen-year period was 533, of which 203 were caused by gas and coal-dust explosions…In Franklin County…the chief improvement has been a better understanding of the dan- gers of gas and a consequent greater respect for it. Formerly, naked lights were often used by fire bosses during their examina- tion, and it was considered a great joke to frighten someone by igniting a pocket of gas." In a June 19, 1924, article by J.E. Jones he detailed how Old Ben, using rock dust, had extinguished seven mine explosions since 1917. "From the experience gained a rough appraisal can be made of the relative effec- tiveness of the various types of rock dust protection, of the means by which the pro- tection may be afforded most readily and of the frequency with which dust applications must be made." In the article, Jones prof- fered his formula for best rock dust mix- tures, his experiments and observations and his drawings for machines to distribute it throughout the mine. The information spread and rock dusting became widely adopted throughout the industry. By May 20, 1926, the U.S. Bureau of Mines had completed a long series of tests and they could state in a piece penned by J.W. Paul and C.A Herbert that "It has been shown in repeated tests in the Experimental *Coal Age, February 25, 1926 Mine of the Bureau that rock dust when properly used is 100 percent efficient." Titled "Rock-Dusting Promptly Checks Coal Dust Explosions," the authors re-tell inci- dent by incident times when coal dust pre- vented the further propagation of an explosion and saved the lives of miners in dusted areas. "Great risk is taken when only part of a mine is treated with rock dust, such as the haulage roads, leaving the aircourses and trackless entries without this protec- tion. A practice such as this invites disaster." However, "rock dust, properly applied and maintained is a panacea for coal-dust explosions, and when its use has become a daily routine at all bituminous coal mines, the wholesale loss of life in mines will be at an end." Preparation: How to Make Coal Float With the June 2, 1921, issue, Coal Age pub- lished the first feature article on the coal flotation process of preparation then preva- lent in England. Written by E.G. Hill of Pittsburgh, the piece describes how, using this process, fine coal attaches itself to oil and bubbles, thus floating away with the froth. Though gravitational methods were used in separating coal from its impurities, "it is now proposed to use oil to collect coal and to make a froth to which coal" and coal fines would adhere. Hill recites how the pro- cess was accidentally determined while chemists were working to separate other types of materials selectively. He also goes on to discuss the use of pyrite, which tends to float as readily as coal. Though the use of heavy media was a new concept as applied to coal, Hill confi- dently believed that "there can be little doubt that the time will come when it will be applied to the reclaiming of fine coal from waste products and to the preparation of low-ash coal from high-ash coal. The pro- cess should appeal to metallurgical coke producers, especially if sulphur be also reduced. The sulphur elimination probably will be a fairly hard problem, but when one considers that in ore concentration pyrite has been made to sink in a pulp while other minerals were floated, its solution would appear possible." Hill closed by stating that experiments on some Pennsylvania coals were then under way at the School of Mines, University of Pittsburgh. "Upon completion of these tests we hope to be able to give more detailed information as to regains, action of materials, etc." While heavy media separation would eventually gain widespread acceptance, 56 www.coalage.com 100th Anniversary Special Issue August 2012