Integrated monitoring technology of water inrush from coal seam floor and its application

Karst water damage in floor is a common problem in North China type coalfield. Because of its characteristics of concealment and emergency, the prevention and control of water is faced with huge problems and challenges, monitoring and early warning technology of floor water inrush has become a necessary measure in the process of the safe production in coal mines. The formation and occurrence of floor water disaster have a process of evolution from conception, development to occurrence. In this process, the corresponding water inrush symptoms will be released in different stages of the floor crack and apparent resistivity of the rock layer. Timely, accurate and effective collection of these information and the specific hydrogeological characteristics in the process of water inrush can be distinguished according to these information. It laid a foundation for the establishment of water inrush monitoring system. According to the three factors of water inrush, an integrated monitoring system of water inrush from the floor is built in the working face 11916 of the east shaft of Gequan mine by using the technology of well ground hole microseismic monitoring and apparent resistivity monitoring. In order to provide a scientific basis for the prediction of water inrush from the floor, the real-time monitoring of the water channel and the water source are carried out. The monitoring results show that under normal conditions, the depth of floor damage in working face 11916 is 20-25 m. However,when the working face was pushed to the middle roadway on September 14, 2019, the superposition effect of the pressure of the haulage roadway and the middle roadway on the floor damage resulted in the increase of the floor damage depth at this location,reaching 30-35 m. The limestone water from Benxi bottom slab entered into the material conveying roadway through the water diversion channel, and the water output from the bottom slab of the working face is 2 m³/h. In addition, from the apparent resistivity monitoring results, we can see the development process of a low resistivity abnormal body from the bottom to the top. The research shows that the integrated monitoring system of water inrush from the bottom slab, constructed by using well ground hole microseismic monitoring technology and apparent resistivity monitoring technology, can capture the signs of water inrush from the bottom slab, It is of great significance and practical value to predict the occurrence of serious and serious water disasters.