Study on new ventilation method of fully-mechanized top coal caving mining face in ultra thick seam

In order to solve the gas overlimit problem frequently occurred during the coal mining process in Tashan Mine,based on No.8105 coal mining face in Tashan Mine as the study object,with the comparison analysis on the gas emission laws of“U"type and“E"type ventilation methods applied to No.8105 coal mining face,a new ven tilation method with"two air incomes and one air returning"was provided. Thus in the“E"type ventilation method,the gas volume fraction of the“T"cross delta area was less than 0. 5% and the gas overlimit problem was solved. Meanwhile,based on the“two air incomes and one air returning"ventilation method,another new“E + I"ventilation met hod was provided to make up the shortage of the unstable air flow in the"E"type ventilation method and to make the conception and idea perfectly to control the gas accum ulation in partial location of the fully-mechanized top coal caving mining face and the gas overlimit at the upper corner of the coal mining face.