Early-warning System Research To Prevent Roof Water Inrush

With increasing of mining intensity and mining depth, water inrush from seam roof occurs frequently, which has caused huge harm to mine safety. It has not only great theoretical significance but also engineering practical value to study seam roof water inrush early-warning system.Based on the study of roof water inrush mechanism and the analysis of the impact factors, the framework of seam roof water inrush monitoring early-warning system was established firstly, and the 4-steps system analysis procedure was presented to monitor, identify, diagnose and evaluate water inrush threat. Supported by fiber grating technology, composed of centre ground stations, underground sub-stations, sensors and so on, the system achieved data collection, data transmission, data processing, real-time display, alarm signal release and other functions. Then, key technical issues of the system as how to choose monitoring indexes, monitoring site location, early warning criteria, and early-warning levels were deeply discussed; the monitoring index system was brought forward, which includes water quality, water quantity, water pressure and water temperature. To establish water quality early warning indicators, an idea was proposed at the first time to study the mixed effects of different water sources through hydro geochemical experiments; By mixed volume ratio experiments using sea water and "the fourth aquifer water" respectively with different aquifer water, the changing characteristics of the indicator ions were acquired, which severs as the experimental basis to determine water quality monitoring threshold; sea water inrush warning criterion was established in terms of the changing rate of indicator ions. Finally, as applications, two typical roof water inrush early-warning projects were carried out at the first mining face H2101 of Bei-zao mine, Long-kou, which was under the sea, and 7130 mine face of Wan-bei Qi-dong mine, which was covered with thick alluvium. The system was running normally in the two different types of roof water inrush threatened mines, the established monitoring indicators and early warning system criterion has begun to be verified. During the mining period of H2101 face, the aquifer water level, water quality and water inflow were within normal range, no sea water inrush signals were released and the working face was safely mined. In 7130 face, no abnormity was found in the monitored water level and water amount, and no alarm was released, the working face realized safety mining.