Characteristics and distribution laws of electric potential response to mining failure of deep coal seam

To study the response characteristics and laws on electric potential(EP) signal of the coal body in the mining failure process, a self-developed mine EP meter was utilized to conduct field tests in the No. 25050 fully mechanized mining face of Xuehu Coal Mine. The results show that the EP signals can be produced significantly during coal seam mining failure process, and the EP response characteristics can reveal the changes of stress state in coal body. As the working face advances, the EP intensity firstly increases and then decreases. The EP intensity decreases significantly after the construction of stress-relief drillings. Simultaneously, the spatial distribution characteristics of EP intensity can identify the zones with abnormal stress in coal seam. The distribution law of the EP intensity and the amount of drill cuttings are similar. When the "stuck" phenomenon occurs during drilling process, abnormal stress is observed in coal body, and the EP intensity reaches a peak value suddenly. The temporal EP signal has the characteristics of precursory response to the hazard of coal and rock dynamic disasters. When the gas indicator exceeds the limit or a large-energy coal cannon event occurs, the EP signal shows a leading increase trend and is accompanied by violent fluctuations. The study results are expected to provide a new idea and an application basis for the utilization of EP methods to monitor coal mining failure and early warning of coal and rock dynamic disasters.