Mechanism and prevention of rock burst induced by horizontal sublevel mining of a steeply inclined extra-thick coal seam

Abstract

In order to prevent the rock burst caused by horizontal sublevel mining of a steeply inclined extra-thick coal seam, the mechanism of rock burst induced by the superposition of dynamic and static loads and the corresponding prevention measures were proposed. Taking Yaojie No.3 coalmine in Gansu Province as the engineering background, the results show that the high concentrated stress caused by the asymmetric distribution of mining stress is the source of static load for rock burst, while the strong dynamic stress caused by the overburden fracture and structural instability is the main source of dynamic load for rock burst. When the total stress reaches the critical stress of large-scale instability of coal-rock mass, the rock burst will occur. Based on the characteristics of dynamic and static load sources, a trinity rock burst prevention and control technology system was established, which comprehensively adopted the deep-hole pre-split blasting in roof for controlling dynamic load, blasting of roadway side and bottom coal or unloading static load by large diameter borehole. The above prevention measures have been successfully applied to the working faces in No.5 mining district of Yaojie No.3 coal mine.

Keywords

• rock burst
• steeply inclined extra-thick coal seam
• horizontal sublevel mining
• static and dynamic stress
• prevention