Abstract
To improve the Bureau of Mines brattice window method of measuring mine stopping leakage, an extensive series of laboratory tests and tests in three operating coal mines were conducted. The laboratory tests defined the window coefficients and the accuracy of the method using different measuring techniques for a range of window sizes and shapes with window areas from 0.0873 to 4.0 Sq ft for flow velocities through the windows from 100 to 1,000 fpm. The results indicated that for the range of window sizes and window flow velocities investigated, a single window coefficient value can be used with little error for each window size and for each flow direction.
