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Generation of Respirable Coal 9
Dust
Chapter Outline
9.1 A Mathematical Model for Respirable Dust Generation 124
9.2 Sample Preparation and Experimental Details 125
9.2.1 Bleuler Rotary Mill 126
9.2.2 Procedure for Grinding 127
9.3 Yield of Respirable Dust 128
9.4 Dependence of Respirable Dust Index on the Properties of Coal 130
9.4.1 Effect of Moisture 130
9.4.2 Effect of Volatile Content or Carbon Content 131
9.4.3 Effect of Ash Content 132
9.4.4 Effect of Fusain Content 132
9.5 Statistical Analysis of Data 133
9.5.1 Correlation Between the Logarithm of Variables 133
9.5.2 Regression Analysis 133
9.6 Results of Similar, Subsequent Studies 134
9.6.1 Srikanth’s Studies 134
9.6.2 Jha’s Studies 135
9.7 Impact of Cutting Bit Wear on Respirable Dust Production 135
References 136
It has been well established that the amount of respirable dust produced in the mining
process is a function of two groups of variables [1,2], namely:
1. Material-dependent variables, such as moisture content, hardness, etc.
2. Breaking mechanismedependent variables, e.g., type of machine, size of cutting tool, depth
of cut, etc.
Studies on size distribution of broken coal have indicated that the breaking mech-
anism (except for bit sharpness) has a significant impact only in the coarser range
(above 100 mm). Their influence on fine dust particle generation is insignificant [3].
It is postulated that respirable dust is not produced by successive breakdown of larger
particles but is rather produced by local crushing of the coal by the cutting bits and
other objects.
On the other hand, physical properties of coal have considerable influence on the
production of respirable dust particles [4,5]. Results of theoretical and experimental
studies are presented in the following section.
Advanced Mine Ventilation. https://doi.org/10.1016/B978-0-08-100457-9.00009-2
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