The voice frequency electric perspective technique for detecting top sand water: A case study at Jisan coal mine

In Jisan coal mine the NO.3 coal seam top sandstone of Permian Shanxi Formation and the bottom conglomerate of Jurassic Mengyin Formation are mainly aquifer,which has obvious characteristics not only in nonhomogeneity but also in strip chart.It is one of important work to detect and deal with these anomalous geologic body rightly in order to insure safety production and improve production efficiencies.The comparison result indicated that when vertical structure of strata is similar and homogeneous in horizontal direction,the higher apparent resistivity and higher abnormal range,the more water is contained in the strata.The water yield is correlated to apparent electric conductivity and abnormal range of voice frequency electric perspective.