Research on hard roof weakening technology of 120306 working face in Songhe Coal Industry
There is a siltstone with a thickness of 12.8 m above the No.3 coal seam of Songhe Coal Industry.It is not only thick but also has good integrity.It is easy to form a large area of suspended roof after the mining of the working face,which seriously affects the safety production of the site.In view of this problem,this paper adopts the methods of theoretical analysis and numerical simulation,and puts forward the method of deep hole pre-splitting blasting to weaken the roof strata.Two kinds of pre-splitting blasting holes were designed.The angle between the pre-splitting blasting hole A and the vertical direction was 20 °,the hole depth was 14 m,the angle between the pre-splitting blasting hole B and the vertical direction was 60 °,the hole depth was 26 m,and the hole spacing was 2 m.Field test was carried out in 120306 working face of Songhe Coal Industry.After deep hole pre-splitting blasting of roof strata,the periodic tension and compression step distance of working face was 18.5 m,and the caving effect of roof strata in goaf was good,which ensured the safe mining of working face.
thick and hard roofpre-splitting blastingborehole parametersroof collapse
万方数据
维普
