| Show REASONS FOR FAVORING USE OF permissible explosives in a statement outlining his reasons for favoring the use of permissible explosives in coal mining operations made by H foster bain acting director of the united states bureau of mines attention is called to the remarkable reduction in recent years in the rate of coal mine fatalities due to the use of explosives in 1903 there were such fatalities in the united states a percentage of of the total number killed and a death rate of per thousand men employed there has been a steady decline in the rate until in 1919 there were but fifty seven deaths from this cause but per cent of the total number of fatalities while 1 le permissible explosives are de signed so that they may be relatively safe for use in gassy and dusty coal mines hies said gj mr bain their strength character characteristics iti make them suitable for other kinds of ma ai ing for railway and construction work and a wide variety of other blasting operations from the standpoint of general safety I 1 they are found to be virtually insensitive to the detonation produced by percussion me tion or flame in order to test permissible explosives the bureau of mines has constructed and maintains a completely equipped testing 4 plant at the explosives experiment station bruceton pa where the explosives are not only tested chemically and physically in the laboratory but elaborately in an experimental mine or artificial gallery the explosives are fired into a number of explosive mixtures such as air and gas air and fine coal dust such as is present in dangerous mines and the results are observed the strength of the explosive is also determined and the results published from time to time in order to keep the user of the explosive informed the gases evolved on the detonation of a bermiss permissible ible explosive are very carefully determined and a limit set by the bureau on the quantity of poisonous gases that the ei plosive may evolve on detonation before the establishment of test requirements by the united states government there were used in the coal mines of tie united states in the year 1902 pounds of explosives which were then called short shod flame explosives while in 1909 after the installation of the pittsburgh testing station of the technologic branch of the geological survey the nucleus out of which grew the bureau of mines pounds were used the greatest quantity of permissible used in coal mines was in 1918 when pounds were used there was a falling off in 1919 due to the decreased production of coal pounds belr being igue use the following table shows how fatalities due to explosives at bituminous coal mine have decreased no percent of NoAil noc 1000 led year killed total killed per g 1903 og 1904 1905 J 1906 26 1907 21 6 1909 1910 0 o 1911 72 1912 70 0 1913 63 1914 56 1915 76 1916 go 60 1 60 1917 55 1918 85 1919 57 |
