Characteristics of Electromagnetic Radiation from Coal or Rock during Excavation and their Applications

Abstract

Electromagnetic radiation (EMR) signals produced during excavation by coal or rock were observed with KBD5, an intrinsically safe coal and gas outburst forecast and monitoring equipment based on electromagnetic radiation. The relationship between electromagnetic radiation signals and excavation or dynamic disaster proneness of coal or rock were analyzed according to these data. The results show that electromagnetic radiation was produced in the course of excavating, which was the result of the stress redistribution or deformation and fracture of coal or rock tending to a new balance after excavation. Obvious electromagnetic abnormal precursors were observed when there existed danger of coal and gas outburst or rock burst, and electromagnetic radiation dropped dramatically after preventing measures were taken. The research results indicate that electromagnetic radiation could be applied to forecast and monitor dynamic disasters such as coal and gas out burst and rock burst.