Characterization of Mass Size Distribution of Respirable Coal Mine Dust by Micron Photo Sizer

Abstract

The mass size distribution of respirable coal dusts has been studied by using micron photo sizer. The respirable coal dust samples were collected at the mine atmosphere during drilling in coal seams by using Messrs. Casella's ‘hexhlet’ apparatus specially designed and fitted with horizontal elutriator to collect the respirable coal dust fraction simulating to the lungs retention conditions of the coal miners. The results showed that the distributions are unimodal, asymmetric and positively skew, with modes usually between 2.5 and 2.9μm equivalent spherical diameter.
Although the assumption of log-normality was useful in interpreting the results, closer observations indicated that the relationship between the size and weight frequency of the particles can be represented by a second degree parabolic equations, W=α+βS+γS², where W and S are weight frequency and size of the particle, and α, β, γ are the constants. The equation characterizes the mass of the respirable particles if the size is known.