Abstract: A method of locating a coal-rock main fracture by an electromagnetic radiation from a precursor of a coal-rock dynamic disaster is provided. At least four groups of three-component electromagnetic sensors are arranged in the underground tunnels, and each group of sensors includes three directive antennas for receiving electromagnetic signals orthogonal to each other. The electromagnetic signals are collected by a monitoring host. The signals are ensured to be received by different sensors synchronously via an atomic clock. The direction of the magnetic field line is determined by performing a vector superposition on strengths of the three-component electromagnetic signals of each group of sensors. The planes of electromagnetic wave propagation perpendicular to the direction of the magnetic field line are determined accordingly. The location of the coal-rock fracture is determined by the intersection point of the planes of electromagnetic wave propagation determined by the multiple groups of sensors.

Abstract: A multi-system, multi-parameter, integrated, comprehensive early warning method for a coal and rock dynamic disaster includes: obtaining monitoring data of a plurality of monitoring systems for the coal rock dynamic disaster, and extracting multivariate characteristic parameters capable of reflecting precursor information of the coal and rock dynamic disaster in each monitoring system based on the monitoring data; screening out a combination of characteristic parameters with a highest early warning effectiveness in each monitoring system and an optimal critical value of each characteristic parameter based on the multivariate characteristic parameters; calculating a comprehensive early warning index and an early warning effectiveness of each monitoring system; and calculating a multi-system comprehensive early warning result of the coal and rock dynamic disaster based on the comprehensive early warning index and the early warning effectiveness of each monitoring system.

Abstract: A multi-system, multi-parameter, integrated, comprehensive early warning method for a coal and rock dynamic disaster includes: obtaining monitoring data of a plurality of monitoring systems for the coal rock dynamic disaster, and extracting multivariate characteristic parameters capable of reflecting precursor information of the coal and rock dynamic disaster in each monitoring system based on the monitoring data; screening out a combination of characteristic parameters with a highest early warning effectiveness in each monitoring system and an optimal critical value of each characteristic parameter based on the multivariate characteristic parameters; calculating a comprehensive early warning index and an early warning effectiveness of each monitoring system; and calculating a multi-system comprehensive early warning result of the coal and rock dynamic disaster based on the comprehensive early warning index and the early warning effectiveness of each monitoring system.

Abstract: A monitoring and forewarning method for coal-rock dynamic disasters based on an electromagnetic radiation and an earth-sound monitoring includes the following steps: (1) calculating the weighted average value of research parameter P(t) during a time period according to the monitoring data collected by the electromagnetic radiation and the earth-sound monitoring system in real time; (2) calculating D(t), the deviation value of P(t); (3) calculating |D(t)| as the deviation threshold value, the average value of |D(t)| during period of normal mining of the working surface; (4) calculating DS, the number of times that D(t) is greater than |D(t)| in one day; (5) normalizing DS to obtain the monitoring and forewarning index ?; (6) forewarning the hazard state of dynamic disaster of the working surface in real time according to ? and forewarning method, determining hazard level.

Abstract: A monitoring and forewarning method for coal-rock dynamic disasters based on an electromagnetic radiation and an earth-sound monitoring includes the following steps: (1) calculating the weighted average value of research parameter P(t) during a time period according to the monitoring data collected by the electromagnetic radiation and the earth-sound monitoring system in real time; (2) calculating D(t), the deviation value of P(t); (3) calculating |D(t)| as the deviation threshold value, the average value of |D(t)| during period of normal mining of the working surface; (4) calculating DS, the number of times that D(t) is greater than |D(t)| in one day; (5) normalizing DS to obtain the monitoring and forewarning index ?; (6) forewarning the hazard state of dynamic disaster of the working surface in real time according to ? and forewarning method, determining hazard level.

Abstract: A method of locating a coal-rock main fracture by an electromagnetic radiation from a precursor of a coal-rock dynamic disaster is provided. At least four groups of three-component electromagnetic sensors are arranged in the underground tunnels, and each group of sensors includes three directive antennas for receiving electromagnetic signals orthogonal to each other. The electromagnetic signals are collected by a monitoring host. The signals are ensured to be received by different sensors synchronously via an atomic clock. The direction of the magnetic field line is determined by performing a vector superposition on strengths of the three-component electromagnetic signals of each group of sensors. The planes of electromagnetic wave propagation perpendicular to the direction of the magnetic field line are determined accordingly. The location of the coal-rock fracture is determined by the intersection point of the planes of electromagnetic wave propagation determined by the multiple groups of sensors.