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Ranking of extinguishing agents against coal dust explosions.
Liebman I; Richmond JK
XVIII International Conference of Scientific Research in the Field of Safety at Work in the Mining Industry, October 7-14, 1979, Dubrovnik, Yugoslavia. 1979 Oct; 1:239-247
The inerting of coal dust by rock dusting is presently the primary means of protection against coal dust explosions in underground mines in the United States. However, rock dusting has not been completely adequate in eliminating coal dust explosions as witnessed by some of our recent mine disasters. As part of a continuous effort to improve mine safety, the Bureau of Mines is conducting research to test and develop additional extinguishing agents for possible use as a supplement to rock dusting. This report describes some of our recent efforts in this field. Three facilities were used in the research: (a) the Bureau's Experimental Mine (CM); (b) a steel surface gallery; and (c) a Godbert Greenwald furnace. Pittsburgh pulverized coal (PPC) containing about 80 pct of particles less than 74 um in diameter and approximately 36 pct volatiles was used in all the experiments. The inhibitors consisted of rock dust (CaCO3), BCD (NaCl), Super K (KCl), Purple-K (KHCO3), BCS (NaHCO3), ABC (NH4H2PO4), water, hybrids of water plus Halon 1301 (CF3Br) or low-expansion aqueous foam plus Halon 1301, and pure Halon 1301. The hybrids had been previously shown to be excellent inhibitors against gas flames. Particle diameter of the rock dust was approximately equivalent to that of the coal dust. The other dust inhibitors were commercial-grade fire extinguishant materials containing fluidizing agents and having particle diameters also similar to those of coal dust. Efficiencies of the extinguishing agents were assessed by (a) the quantity of agent required when premixed with the coal dust to prohibit flame or explosion propagation; and (b) the quantity of agent dispersed from a triggered barrier necessary to stop a propagating coal dust explosion.
Mining industry; Mining; Underground mines; Underground mining; Coal mines; Coal mining; Coal dust; Rock dusting; Explosion prevention
OP; Conference/Symposia Proceedings
XVIII International Conference of Scientific Research in the Field of Safety at Work in the Mining Industry, October 7-14, 1979, Dubrovnik, Yugoslavia
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division