Prediction Of Water Inrush Risk On Coal Seam Roof In Xiao Zhuang Coal Mine

Due to the main mining layer 4 coal seam is buried deeply and mining thickness is big in Xiao Zhuang coalmine, carving zone will be may communicate overlying aquifer of Luohe formation, which will led to roof bursting water disaster is occurred. And Luohe formation aquifer is the main aquifer in minefield. Its distribution range is wide, thickness is big, watery is strong. If the water of Luohe formation aquifer become the source of mine bursting water will brings serious damage to mine. Therefore, water inrush from roof coal is an important factor to restrict Xiao Zhuang coal mine safety production, improve the accuracy of risk prediction of water inrush from roof coal have important practical significance for prevention and control of Xiao Zhuang coal mine roof water disaster, will be very important reference for safety production of Xiao Zhuang coalmine.Based on the analysis of coalmine geological and hydro-geological conditions, do a watery partition for layer 4 coal seam’s roof sandstone of Luohe formation aquifer. Divided Luohe formation sandstone aquifer into three areas which include the watery weak area, watery medium-rich area and watery strong area. Using numerical simulation software FLAC3 D simulate the overburden failure law of first mining face-40201 working face after the coal seam is mined. Simulation results show that the firt weighting step is 40-60 m after the coal mining of 40201 working face, and the largest height of breaking belt is 176 m, ratio of the height of breaking belt to the mining height is 13.5.Comprehensive analysis the measured crack belt height height of adjacent mines and qualitative analysis the data, previous experience formula to calculate data and simulated data, to conclude a crack belt height estimate formula of empirical in Xiao Zhuang coalmine. By comparing the projected height of 4 seam risked splitting and 4 coalseam roof to Luohe Formation aquifer of the bottom of the range, do grading prediction for safety fractured zone of Luohe formation, divided into dangerous fractured zone, high risk fractured zone, risk fractured zone and safe fractured zone. Used “Three Maps-Two Predictions” Method, do a superimposed analysis for Luohe formation of watery partition figure and risk crack security partition figure, classified the water bursting hazard of coalmine roof from big to small as four areas for dangerous area, high risk area, medium risk area and risk area.The result showed that dangerous area and high risk area accounted for 53.6%. So, it is recommends the mine should strengthened control efforts of roof flood.in the mining.