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The control of coal dust is difficult due to the coal dust being such a fine particle, allowing it to escape and be suspended in the air for a large amount of time. [3] Dust explosion pentagon showing the needed elements for an explosion: Oxygen, Combustible dust, Dispersion of dust, Confinement of dust, and an Ignition Source.
The stress regime at the face - high stress on and around the mining face can close up the cleats and pores in the coal seam. This can result in a steep coal seam gas pressure gradient into the seam, (as opposed to a low stress environment where the coal seam gas drains freely into the face area, resulting in a low seam gas pressure gradient).
Rock dust is a pulverized rock, usually limestone, sprayed on walls inside underground coal mines to prevent coal dust explosions. The dust acts as a heat sink, keeps coal dust levels down, and also prevents the incidence of black lung disease. Rock dust has been used since the early 1900s, but technological improvements have occurred. [1]
On the morning of Aug. 4, 1917, a methane gas explosion at the Western Kentucky Coal Company’s No. 7 mine in Webster County killed 62 of the 153 men underground at the time. The other 91 men in ...
Ignited methane gas is a common source of explosions in coal mines, which in turn can initiate more extensive coal dust explosions. For this reason, rock dusts such as limestone dust are spread throughout coal mines to diminish the chances of coal dust explosions as well as to limit the extent of potential explosions, in a process known as rock dusting.
The buildup of pressure in the strata can lead to explosions during (or after) the mining process if prevention methods, such as "methane draining", are not taken. [ 58 ] In 2008 James E. Hansen and Pushker Kharecha published a peer-reviewed scientific study analyzing the effect of a coal phase-out on atmospheric CO 2 levels.
Lab demonstration with burning lycopodium powder. A dust explosion is the rapid combustion of fine particles suspended in the air within an enclosed location. Dust explosions can occur where any dispersed powdered combustible material is present in high-enough concentrations in the atmosphere or other oxidizing gaseous medium, such as pure oxygen.
The presence of coal dust in the air increased the risk of explosion with firedamp and could cause explosions even in the absence of firedamp. The Tyneside coal mines in England had the deadly combination of bituminous coal contaminated with pyrites and there was a great number of deaths in accidents caused by firedamp explosions, including 102 ...