Rock burst risk assessment of working face during open-off cut based on acoustic emission monitoring

Abstract

Impact risk assessment is a work that must be carried out in driving and stoping stage in mining coal seam with impact risk to ensure the safety of driving and stoping working face. As one of the methods to evaluate the impact risk, ground acoustic emission monitoring has been widely used in the monitoring and evaluation of the impact risk of coal seam. Ground acoustic emission monitoring system was used to monitor the driving process of opening hole in the first section of working face at the 21st floor in the south area of the second level of a mine in real time, and then to evaluate the impact risk. A method was proposed to classify the impact risk by using ground acoustic emission anomaly index. Combined with the actual occurrence of rock burst, the analysis of ground acoustic emission data shows that the continuous increase or silence of single channel activity and the sudden increase of two or more channels activity indicate the increase of impact risk, and can be used as the ground acoustic emission precursor information before the occurrence of rock burst. According to the statistics, the accuracy rate of ground acoustic emission monitoring is 66.6%, which indicates that ground acoustic emission monitoring has a good effect on impact risk assessment.

Keywords

• open-off cut of working face
• ground acoustic emission monitoring
• rock burst risk assessment
• anomaly index
• precursory information
• accuracy rate