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U.S. Department of Energy
Office of Scientific and Technical Information

Improved method for evaluating the incendivity of explosives to coal dust: a progress report

Technical Report ·
OSTI ID:7081254
Experience with the current version of Gallery Test 4, in use since 1913 to evaluate the incendivity of permissible explosives in the presence of coal dust, has shown the procedure to have inadequate discrimination. Consequently the Bureau of Mines used the up-and-down method of statistical design to investigate the incendivity of permissible explosives in the presence of coal dust and gas. A suitable device was developed to measure coal-dust concentrations in the air-gas mixtures and to disperse the dust in the gallery atmosphere. A proposed testing method which uses suspended shots in a predispersed coal dust-gas-air mixture was evaluated. The new method can discriminate between different explosives with respect to their incendivity. Maximum ignitibility of the coal dust cloud by permissible explosives occurred in the vicinity of 0.3 oz/cu ft. About 10 percent sodium chloride in permissible explosive formulations had a very significant effect in reducing the probability of igniting coal dust. Bundled charges were more incendive than column charges.
Research Organization:
Bureau of Mines, Washington, D.C. (USA)
OSTI ID:
7081254
Report Number(s):
BM-RI-6815
Country of Publication:
United States
Language:
English