CDC Mining Topic Rock Dusting NIOSH
Jun 17, 2019#0183;#32;Through largescale testing, NIOSH researchers determined that 80% total incombustible content when mixed with coal was needed to prevent dust explosions in intake airways. The
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Jun 17, 2019#0183;#32;Through largescale testing, NIOSH researchers determined that 80% total incombustible content when mixed with coal was needed to prevent dust explosions in intake airways. The
Proper rock dusting practices have proven to be an effective means of preventing coal dust explosions. Rock dust (generally pulverized limestone dust) serves as a heat sink material that prevents or suppresses a propagating coal dust explosion through the absorption of thermal energy from the heated gases and absorption of radiant energy, which reduces the preheating of unburned coal
The paper discusses the influence of rock dust particle size on the inerting requirment of coal dust/air mixtures using coal from the Prince mine of the Cape Breton Development Corporation, Nova Scotia. Two size fractions (fine and coarse) of coal and several
Coal dust explosions in underground coal mines are prevented by generous application of rock dust (usually limestone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents flame propagation by acting as a thermal inhibitor or heat sink.
Anatomy of a Float Coal Dust Explosion Coal combustion front Underlying rock dust dispersion lags behind the combustion front and unable to quench combustion front Surface coal dust disperses first Layered dust Float coal dust ( mm or in) Rock dust ( mm or in)
1/12/2019#0183;#32;The purpose of the rock dust is to disperse with the coal dust and act as a thermal heat sink and to block radiant energy transfer to the coal particles to prevent sustained coal dust explosion propagation. 30 CFR, Subpart E (Combustible Materials and Rock Dusting) requires the use of rock dust in bituminous coal mines to abate the hazard of accumulated coal dust . The regulations
1/7/2007#0183;#32;In the rock dust inerting tests, the coal dust and limestone rock dust mixture was placed half on roof shelves and half on the floor. The nominal dust loading reported for the LLEM tests assumes that all the dust was dispersed uniformly throughout the cross section. For the LLEM tests, Ddrift was thoroughly washed down several days before the test to allow the entry to dry before the day of
1/6/2017#0183;#32;Proper rock dusting in underground coal mines can effectively eliminate the two conditions for coal dust to participate in explosion. The inert rock dust can function as isolator, physical heat sink and chemical energy absorber. The heavier rock dust applied over the lighter coal dust can serve as an isolator to prevent the coal dust underneath from becoming easily airborne. The isolator is
If a sufficient amount of rock dust is added to the coal dust, the mixture is rendered inert. The rock dusting regulations are based on the results of fullscale experimental mine tests as summarized by Nagy (1 98 1). NIOSHPRZ, conducts dust explosion research in its Lake Lynn Experimental Mine (LLEM) and in laboratory chambers. Postexplosion
In light of this recent comprehensive dust survey, NIOSH conducted additional largescale explosion tests at the Lake Lynn Experimental Mine (LLEM) to determine the degree of rock dusting necessary to abate explosions. The tests used Pittsburgh seam coal dust blended as 38% minus 200 mesh and referred to as mediumsized dust. This mediumsized blend was used to represent the average of the
Coal dust explosions in underground coal mines are pre#173; vented by a generous application of rock dust (usually lime#173; stone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents ame propagation by acting as a thermal inhibitor
Coal Dust Particle Size Survey MSHA. the sample to remove the limestone rock dust, sonic sieving to determine the dust size, and lowtemperature ashing of the sieved fractions Experimental studies by the Pittsburgh Research Labora with coal dust will prevent coal dust explosions by acting as term ''''inert'''' in this sense means that the material does price
sized nontreated rock dust under the same experimental test conditions. Fundamental research has . been conducted in the EMB on a largescale basis since 1925 to address the explosive danger of coal dust, firedamp and flammable fire gases [Cybulski, 1975]. Such research includes examining main explosion parameters, rock dust suppression effects, initiator effects, accumulations of fire damp
Coal dust explosions in underground coal mines are pre#173; vented by a generous application of rock dust (usually lime#173; stone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents fl ame propagation by acting as a thermal inhibitor or heat sink. To investigate this process in more detail, a number of ex#173; plosion experiments using various coal dust
Because the volume of rock dust which can be dispersed over a given time frame is limited by the 2014 dust rule, that rock dust application method tends to limit productivity of the mine and does not allow for a timely dusting of the mines , exposed coal seam, thereby increasing the amount of coal mine dust that has the potential to be fuel in the event of an explosion because it is
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