Methods for calculating specific air leakage in loose coal of fully mechanized longwall top coal caving face

It is significant to calculate specific air leakage for studying the predicting technique of coal self ignition of loose coal. As the actual air leakage velocity is very small and the conditions of gates in the coal mine are complicated, the general methods,i e. the testing technique of air flux and air press cant be applied to loose coal of gates. The new method which the air leakage is calculated with the oxygen concentration and the rate of oxygen consumption by coal is put forward. It is accord with the actual air leakage in the gates. At last the dynamic effect of the thermal air press on the specific air leakage is analyzed. The rightness of results is proved in site for predicting spontaneous combustion in tailgate of face 4308 in Dongtan Coal Mine.