Research On The Gas Emission Characteristics And Key Technology To Control During Initial Mining Period Of Hard Roof And High Gas Fully Mechanized Mining Face

During the normal backstopping of15#coal seam,gas which comes from neighboringcoal seam can be drainaged effectively by Mining-induced fracture. However, there isimmediate roof that will collapse during the initial mining period，the old and hard roof cannot collapse timely which lead to the result that high level suction roadway can not beconnected by Mining-induced fracture,a large number of gas coming from top neighboringcoal seam flows into coal face which slows down mining speed and increases airvolume.15101and15108fully mechanized mining face had varying degrees gas problemsduring initial mining period.This article analysis the gas source on the initial period of hard roof fully mechanizedmining face.We get relative parameters of gas emission on the initial mining period of15202and15109fully mechanized mining face by field observation and dataanalysis.Further analysis can get the law and parameters of roof settlement.Research results get the reason of gas problem on the initial mining period,find theentry point that how to collapse hard roof timely which connect high level suction roadwayby Mining-induced fracture.Gas should be drainaged effectively before and after hard roofcollapse.Based on the current gas comprehensive control techniques of initial miningperiod,system of gas comprehensive control techniques of initial mining period is putforward.By the way of numerical simulation and field measurement,this technique systemis proved to be effective.This technique system is used to solve gas problem of15203fullymechanized mining face,it achieves good results.