An approximate design procedure for single entry drifts having a leaky brattice

The efficiency of auxiliary ventilation by a brattice is given in a simple exponential expression. This expression is derived from and compared with the complete analytical solution of the leaky brattice. The equation requires only measurable properties of the drift and the working face flow requirements.

There is excellent agreement between the approximate and exact solution. The maximum relative error is less than 0.3%. There was also good agreement between the approximate solution and experimental data from three drifts in potash mines. The average difference in the pressure differences and the flow is about 7%. It is shown that the fitting equation is more accurate than the experimental data.