Features of longitudinal diffusion of contaminants in long mine workings

Abstract

1. It is shown that the concentration field of a contaminant at any distance from the point of its injection (emission) into a current of mine air is fairly exactly represented by the known solutions of the equation of unidimensional diffusion (heat conduction). The agreement between the calculated and measured data is improved if we assume that each branch of the impurity concentration curve in the cloud is characterized by its own coefficient of longitudinal diffusion. 2. If one of the coefficients of diffusion for the corresponding branches of the distribution curve of contaminant in a long working is several times larger than the other, then the contaminant cloud as a whole is diffused under the influence of the greater one, due to disturbances created either in the face zone or along the working. 3. The authors derive equations for the parameters of effective air exchange in long blind or open-ended workings and for the quantity of gaseous contaminants (N2O, etc.) adsorbed by the walls of the working.