Theoretical and Experimental Studies of Localization Methodology for AE and Microseismic Sources Without Pre-Measured Wave Velocity in Mines

The acoustic emission (AE) and microseismic (MS) monitoring are efficient methods to detect faults/breaking signals for both healthy evaluation and disaster control in mining engineering. This paper presents an MS or AE source location method without the need for a pre-measured wave velocity. It can eliminate the location errors for MS/AE monitoring systems caused by the deviations of the wave velocity. To verify the applicability of the proposed method, first, tests of both the pencil lead break and the thermal fracture in granite were carried out, and location errors were compared and analyzed. Results show that the location accuracy of the proposed method is significantly improved, which is superior to the results of the traditional location method (TM) using pre-measured wave velocity. Second, blasting experiments were carried out in Dongguashan copper mine in China. The blasts were used as simulated seismic sources. Average values of absolute distance errors of the MS/AE source locations resulting from the proposed method without wave velocity and the traditional method using average measured wave velocity are 10.16 and 17.55 m, respectively. It shows that the calculated locations by the proposed method are in better agreement with the real blast coordinates. Third, the proposed method is also applied to previously published data. It gives superior results compared with the considered existing methods. Results of the pencil lead break tests, the thermal fracture experiment in granite, and the blasting experiments (including published data) have demonstrated that the proposed method can not only decrease the location errors induced by measurement deviation of velocity, but also locate the MS/AE source in real time, which is a beneficial complement to the method TM in mines.