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which contrasts with an average for the coal fields of North America of 0.91. But the excessive shaft accident rate for Illinois is by no means an exception. In Indiana the combined rate was 2.87, for Oklahoma 3.11, for Iowa 2.18, for Nova Scotia 2.61, and for Washiington 3.99 per 10,000. Accidents of this kind constitute, therefore, quite an important factor in the fatality rates of certain States, and it may be assumed that if the returns were everywhere accurate and complete the true fatality rates due to shaft and cage accidents of all kinds would be higher than the rates as officially returned and given in the above table and in Table XXIII of the appendix. (9)
Mine cars caused 2.201 fatal accidents in the North American coal fields during the decade ending with 1908, out of a total of 18,316 accidents from all causes. The standard or average fatality rate due to mine cars was 4.04 per 10.000 employees, but the rates vary considerably in the different coal areas, as shown by the following table: FATAL-ACCIDENT RATES IN COAL MINING IN NORTIL AMERICA DIE TO MIXE
CARS, FOR THE PERIOD 1899 TO 1908.
The mine car fatality rate ranges from a minimum of 2.05 per 10,000 for the west-central section to 8.01 per 10.000 for the Pacific coast section. Mine equipment, of course, has a bearing upon the degree of accident occurrence, but how far this is the case can not be determined by the brief account rendered in most of the official reports on accidents of this class. Riding on loaded cars contrary to orders is probably one of the chief reasons for the difference, and another probable reason is in the better discipline and control of mine labor in the Eastern States compared with the South and West.
Among the States and Provinces, with rates of mine car fatalities much above the average, reference may be made to British Columbia with a rate of 7.63; Colorado, 7.01; Oklahoma, 7.26; l'tah, 8.33; Washington, 8.37; and West Virginia, 6.18 per 10,000.
a See also the Report of the Committee appointed by the Royal ('ommission on Mines to Inquire into the Causes of and Means of Preventing Acridents from Falls of Ground, Underground Haulage and in Shafts; Parliamentary paper (d. 4521, London, 1909.
classified. Granting probable defects in the returns, it is surprising to find that the fatality rate due to motors should be as low as 0.06 per 10,000 in the eastern coal field, which comprehends the States of Maryland, Pennsylvania, and Ohio. In Illinois, for illustration, out of 1,391 fatal accidents only 4, or 0.08 per 10,000 employed, were officially ascribed to motors, while in Ohio 19 out of 1,027, or 0.17 per 10,000 employed, were attributed to this cause. No deaths due to motors were officially reported as having occurred in the coal mines of Pennsylvania, which, no doubt, is partly due to errors in classification. For these reasons, it would serve no practical purpose to discuss the fatality rates due to motors in the different coal areas and coal mining States, but the self-evident defect in coal mining statisties clearly brings out the necessity of a uniform classification of causes to be agreed upon by the mining officials of the different States.
EXPLOSIONS OF GAS OR DUST. Statistical defects are inherent in all classification, but they can be materially reduced by a critical examination of individual returns. Of no group of causes is this more true than of gas and dust explosions, explosions of dynamite and powder, blasts, etc. There are practical difficulties to be overcome which at times will baffle even the most skilled, for cause and effect will often be confused, and it will occasionally occur that the true but insignificant cause of a coalmining accident is overshadowed by the disastrous effect. A can of powder explodes and results in a subsequent gas and dust explosion with a considerable loss of life. Should such an explosion be classified under explosives or explosions? Or, a naked light ignites fire damp and causes a small gas explosion, which results in the explosion of an underground powder magazine, with disastrous results to life. Should such an accident be classified as gas explosion, or as a powder explosion? A compromise is necessary in such cases, but it would be of great value if definite rules gorerned in the statistical classification. It is due to these differences in the determination of the true cause that so many apparent errors and contradictions occur in coal-mining accident statistics and without a definite understanding among the different mine officials, a decided improvement can not be expected for many years to come.
As classified in Table XXIII of the appendix, there have been 2.571 fatal accidents due to gas and dust explosions in the coal fields of North America during the period under consideration, or 11 per cent of the fatalities due to all causes. The standard or average rate of accident frequency was 1.71 per 10,000, against 4.04 for mine cars and 1.77 for deaths due to explosions of powder or dynamite. Gas and dust explosions, therefore, are among the most important causes of mining
clude the sprinkling of dry mines previous to the setting off of blasts, as perhaps the only effective method of precaution. It has been objected to this method, however, that sprinkling favors the spread of ankylostomiasis, with its well-known serious consequences to the miner's health. The sprinkling or spraying of dry mines is made obligatory in most European countries, and it can only be a question of time when this preventive will be insisted upon in the United States; but strong objections are made to the practice, which must be overcome by education and the perfection of sprinkling or spraying methods, as vet quite crude and often ineffective.(a)
The dust factor is clearly recognized in Alabama, where the accident rate due to gas explosions, officially returned as such, was only 1.98 per 10,000, while the rate for dust explosions was 8.67, or a combined rate of 10.65. No dust explosions have been officially reported as such from British Columbia, but the rate for explosions of gas alone was 7.85 per 10,000, or nearly twice the standard or average rate for the coal fields of North America. For Colorado the rate has not been particularly excessive, or 2.96 for gas explosions and 1.38 for dust. For Illinois dust explosions have not been separately returned, and the rate for gas explosions was only 1.34. Since 1909), however, the disastrous explosion at Cherry, Ill., has furni-hed lamentable evidence of the inherent uncertainty in all calculations of this kind. Normally, however, the risk of gas or dust explosion in Illinois is below the standard. The fatality rate due to gas explosions in Indiana has also been very low, while for Oklahoma it has been extremely high, or 10.02 per 10,000. The rates have been low in Iowa and Kansas, Kentucky, Maryland, and Missouri. In New Mexico the gas-esplosion rate was 2.18 per 10.000 and the dust-explosion rate 6.52, or a combined rate of 8.71 against a standard rate of 1.71. The rate was below the average in Nova Scotia, Ohio, and Pennsylvania anthracite, but above the average in Pennsylvania bituminous mines. In the Pennsylvania anthracite coal field the rate from gas and dust explosions combined was 2.13 per 10.000, while for the bituminous coal field the comparative rate was 5.23. These rates are insignificant compared with the rate for Tennessee, which was 0.21 for gas explo
Dust," by Wilber F. Meyers, Engineering and Mining Journal, February 22, 1908; “ Coal-dust as a Dangerous Element in Mining," article by 11. C. Hovey, American Jourual of Science, volume 122, page 18; “ The Dust Danger," by W. H. Pickering, Engineering and Mining Journal, May 12, 1900); " English Experiments in Coal-dust Explosions," Scientitic American Supplement No. 147). October 17, 1903; Argument that coal-dust is not explosive, by Wm. M. l'age, an open letter to the mine operators of West l'irginia, Engineering and dining Journal, December 5, 1908.
• For a full discussion of the whole problem of coal-lust explosions, the prevenion of coal dust and its removal, methods and cost of watering or sprinkling. etc., see Second Report of the Royal Commission on Jines, p. 82. London, 1*19.