Abstract
Dust flow after a mine blast in a semi-infinite airway is studied experimentally and analytically. The field data are used to define the initial and boundary conditions for the general dust flow equation and to develop some formulas for the boundary problem and the nonmeasurable analytical constants. A simplified mathematical solution describing removal of an airborne dust from a cut-and-fill stope is proposed and verified. Conclusions based on comparison of the analytical and measured concentrations are presented. The effects of the amount of blasting material and the ventilation system in use on dust concentration are discussed. Two monitors (model Ram-1) and a data logger system recorded dust concentrations (up to 200 mg/m3) every 10 seconds after several blasts in the cut-and-fill stopes of a hard rock metal mine. It was found, based on the data collected in situ, that the initial dust in the semi-infinite airway is marginal and that the inflow of dust at the airway entry changes exponentially with time. The field data were then utilized to specify the analytical forms for the initial and boundary conditions for the general partial differential convection-diffusion equation, and to provide Equation 6, the simplified solution for the flow of dust in a mine applying the cut-and-fill mining methods. The terms in Equation 6 do not account for any initial dust or deposition of dust along an airway.