Study On Roof Caving Disaster Of The Longwall Face Mining In Proximity Beneath A Room Mining Goaf In Hanjiawan Coal Mine

Roof disaster is one of the disasters that can not be ignored in the production of coal mine.Especially for the geological conditions of shallow burial and thin bedrock in the northwestern part of the coal seam,when the fully mechanized coal mining face is arranged in the pillar goaf area,the roof of the coal seam is more prone to instantaneous caving.This has a huge impact on the safe mining of the mine.Therefore,it is of great practical significance to carry out the research on the roof caving disaster of the longwall face mining in proximity beneath a room mining goaf.In this paper,taking 3301 fully mechanized Hanjiawan coal mine as an example,using the research methods of theoretical analysis,numerical simulation and engineering verification,on pillar stability of goaf,room and pillar under goaf of close coal layer mining roof fracture form and goaf in coal pillar after blasting coal mining under the movement rule of overlying strata and the strata characteristics were analyzed.Based on the combination of nonlinear theory and numerical simulation,the stability of the room and pillar mining area above the 3301 working face is evaluated.This paper constructs a double key layer model of the 3301 working face in the coal mine,and analyzes the roof fracture mechanics of the 3301 working face,and obtains the criterion of roof instability of the 3301 working face.The numerical simulation of coal pillar splash blasting and non-blasting in coal pillar coal mining area are carried out to reproduce the law of overburden and the process of coal pillar stress evolution.The above analysis results have been verified in the mining practice of the 3301 working face in the Hanjiawan coal mine,which provides an example to solve the safety problems faced by the overburden pillar goaf in the near coal seam of the Yu Shenfu mining area.