Study On Mining And Safety Guarantee Technology Under The Goaf Of Upper Layer In 1^-2 Seam Of HuoJitu Mine

The coal seam of the 1-2 coal complex in the HuoJitu of DaLiuta coal mine is 76?106m deep and the thickness is about 10m.Due to the limited level of equipment manufacturing industry at home and abroad at that time,from March 2001 to May 2006,Shendong Company adopted the comprehensive mechanized mining method to extract 5.0 hydraulic support for the coal seam in the panel,the mining height was 4.5-5 m,the remaining 5 m thick coal seam was retained under the goaf of the upper layered,and the remaining coal resources exceeded 30 million tons were not recovered,after redesign,the mining work could be arranged 9 faces.Taking the mining engineering of 202 working face of 1"2 lower seam as an example,this paper makes a comparative study on the technology of fully mechanized mining overall height in one times and fully mechanized top-coal caving mining,and reasonably determines the optimum mining method for resource recovery under goaf.By means of theoretical analysis,numerical simulation and similar material simulation test,the scientific and rationality of top-coal caving mining method has been verified.The caving performance of top coal is better under the action offloor failure in upper layer mining process and repeated support of hydraulic support in this working face.Engineering practice shows that the mine pressure appearance of working face is not obvious,the periodic weighting step is 4.8-14.9 m,with an average of 8.1 m,and the support load is 9153-10026 kN,with an average of 9434 kN.The design of matching hydraulic support can meet the needs of field mine pressure appearance.In view of the safety risks of the excavation and mining operations under the condition of extremely short-range goaf,the safeguard measures for safe mining are also studied and formulated,and a set of systematic technical system is established from the determination of mining methods-rationality verification-roadway safe driving support scheme-safe mining measures,which provides a basis for the subsequent mining of the working face.The efficient and safe mining of this working face also provides a good reference for the recovery of coal resources under similar conditions at home and abroad.It contributes to the sustainable development of non-renewable coal resources in our country.