Analysis of structure collapse regularity for overlying strata in stope based on microseismic technique

Abstract

To study the structure collapse regularity for overlying strata in stope under the influence of mining, detect the fracture distribution state of coal and rock mass in working face. A multichannel ESG microseismic monitoring system was established to monitor real‐time and continuous microrupture of overlying strata by the advanced mining dynamic disaster monitoring equipment at the working face 62114(C14) in the Xinzhuangzi mine. A large number of monitoring data under the conditions of working face mining process are obtained. The relationship among 3D microseismic location event clusters, fracture zone and structure collapse regularity can be analysed. The layout plan of methane extraction drainage boreholes are finally determined based on the different methane rich zones. The results indicate that the working face advanced, microevents become more and more, the microseismicity of overlying strata is obvious at different times; mining induced stress field change, the appearance of high stress zone impels the microfracture to germinate, and microfractures as a pathway resulted in methane desorption, migration and interconnection in the goaf. The fracture zone and methane rich zone were located in the goaf, close to the retained gateroad. Therefore, the microseismic technique can provide a new and comprehensive way in researching the evolution rules of covering working face rock.

Keywords:

• Microseismic technique
• Fracture zone
• Methane rich zone
• Overlying strata
• Structure collapse

This material is based on work partially supported by the National Science Foundation (grant no. 40638040 and no. 50909013); International Important Cooperation Project (project no. 50820125405). Any the opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the projects.