TABLE 2.-Production of coal and number of men killed per million tons of coal produced during 1925 and the 10-year period 1916-1925 1925 1 Number killed per million tons ACCIDENT RATES OF MINING AND OF SURFACE INDUSTRIES Table 3 compares fatalities in coal mines per thousand 300-day workers in the typical years 1915, 1919, 1923, and 1925 with those in the mining of various metals and in two surface (metallurgical) industries. It shows that coal mining is more hazardous than metal mining, which in turn is much more hazardous than the two surface industries. The table also gives the number of 300-day metal miners per thousand killed or injured and indicates that the liability to an injury is 40 to more than 100 times greater than that to a fatality. As yet no general statistical figures are available for coal-mine injuries in the United States. The British coal-mine statistics for 1924 on injuries causing disabilities of more than 3 days indicate a ratio of 163 injured to 1 killed, and in 1925 of 158 injured to 1 killed. If a similar but lower ratio (to be conservative) were applied to coal mining in the United States (for example, 100 injuries to 1 fatality), mortality records for 1925 would indicate the probability of 223.000 injuries of all kinds for the year. In other words, about 30 per cent of all mine employees would be injured in some way during that year. TABLE 3.-Number of men killed and injured per thousand 300-day workers in 1915, 1919, 1923, and 19251 1 From Adams, W. W., Coal-Mine Fatalities in 1926: Bull. 283; Bureau of Mines, 1927. 'Figures not available. Table 17 of Bulletin 283 gives details of the principal causes of fatal accidents in coal mining and is reproduced below as Table 4. TABLE 4.-United States: Coal-mine fatalities by detailed causes, 1917 to 1926 The cause of the fatalities due to explosions of powder, as given by some State statistical bureaus, is open to question. Some of the explosions of gas and dust attributed to this cause should possibly be grouped under "(d) Due to shot," of item 4, "Explosion of gas or dust" in Table 4. TABLE 4.-United States: Coal-mine fatalities by detailed causes, 1917 to 1926— CHIEF CAUSES OF COAL-MINE ACCIDENTS The principal causes of the fatal accidents listed in the foregoing tables will be discussed and appropriate recommendations made in the following order, which is not the order of the risk to any individual miner as shown statistically but the relative order of magnitude of the precautions that must be taken by mine managements to abate the respective accidents: (a) Explosions of gas or coal dust. (c) Mine fires. (d) Falls of ground. (e) Haulage accidents. (f) Electric shocks. (g) Miscellaneous underground, including inrushes of water. (h) Shaft accidents. (i) Surface accidents connected with dumping, screening, and loading coal; also accidents in the power house and shops. ORGANIZATION, ADMINISTRATION, AND REGULATION Before taking up the detailed discussion of each of the above groups of accidents it is advisable to bear in mind that abatement of the accidents in any one of the groups involves considerations of four important factors-organization, administration, planning, and discipline. Unless each of these factors receives adequate attention, reasonable freedom from accidents is impossible. Coal mining is admittedly hazardous. The industry has already done much to overcome natural hazards, but far more can be done to lessen injuries and deaths, which are becoming a matter of national concern. 7 EXPLOSIONS OF GAS OR COAL DUST Explosions of gas and coal dust, separately or together, have killed thousands of coal miners in this country during the past quarter century. As a matter of fact, fatalities from falls of roof or coal are far more numerous and for the country as a whole occur almost hourly. A fall, however, rarely kills more than one or two men and fatalities from falls get little notice, whereas explosions, some of which kill many men, attract wide attention and are far more dreaded. Major explosions in this discussion, as in the statistical publications of the Bureau of Mines, are those that cause the death of five or more persons. Fortunately they are rare, and virtually all are coaldust explosions in bituminous mines. There has been an average of about eight such disasters a year in bituminous mines in the 25 years 1900 to 1924; but the annual toll of fatalities averages 252 and ranges from 868 in 1907 to 16 in 1921. Peaks were reached in 1924 (444 deaths) and 1925 (244 deaths). Local and shot firers' explosions of gas and bituminous dusts have been vastly more frequent, but a number of them have not killed anyone because they were started by shots fired electrically from outside the mine; however, the yearly average number of deaths from such explosions during the 10 years ended 1925 is 87 men. This figure includes deaths from local explosions of gas in the Pennsylvania anthracite district, where the dust is not explosive. Some explosions that were local might have become great disasters if the condition of the coal dust or the proportion of gas in the air current had happened to favor propagation of the initial explosion. One fact must be borne in mind—without adequate ventilation and safeguards from ignition underground coal mining on a large scale would hardly be possible to-day. Precautions against explosions are therefore a primary requirement in coal mining and demand consideration even beyond that given falls of roof, which kill far more men. It is believed that major explosion disasters can be eliminated by the preventive measures described herein. METHODS OF PREVENTING MINE EXPLOSIONS 1. Ventilation, to dilute and carry inflammable gases out of the mine; suitable methods of determining the proportion of such gases in the mine air, to guide the management in furnishing adequate ventilation in every part of the mine. |