On the role of ascending diffusion of a gas flowing into the drift

We investigate the effect of ascending diffusion associated with the distribution of the hydrostatic pressure over the depth on the methane flow to the coal drift. The diffusion problem is solved analytically with the help of integral transformations. It is shown that the integrated gas flux is an exponential function of the drift depth. In view of the competition between transport modes associated with concentration and pressure gradients, the flux decays exponentially over a long time. The expressions for the integrated flux and for the flux at a preset instant are obtained. The role of symmetry in the problem of stress distribution in the medium surrounding the drift is considered.