Small scale model simulations of methane gas in coalmines.

An aerodynamic small scale model of a retreat longwall coalface is described. This model is based on scaling relationships which define the conditions needed to achieve flow in the small scale similar to that in the full scale in all important aspects including gas density, formation of layers, turbulence, pressure gradients, flow through the waste and dispersion in the waste. Simulations have examined how the concentrations of gas near the face end are affected by the location of gas sources, rate of gas emission, seam slope, ventilation flow, the geometry of the coalface, and the interaction of some of these. Simulations with variation of one parameter (seam slope) are presented to illustrate the scope of the model. 9 refs., 1 fig., 1 tab.