Gong-kuang zidonghua (Oct 2023)
Design of high-resolution electrical monitoring system for mining
Abstract
The resistivity method is an important means for identifying, monitoring, and warning potential risks of coal mine water hazards, and also an important data source for transparency of mine geological information. When conducting underground electrical monitoring, the positioning precision of single roadway electrical profiling method or double roadway electrical perspective method for water rich areas is not high. In addition, due to the increasingly strong electromagnetic interference generated by large-scale electrical equipment, traditional electrical monitoring equipment is difficult to obtain effective data. In order to solve the above problems, a high-resolution electrical monitoring system for mining has been designed. The system can automatically collect data from single roadway electrical profile method and double roadway electrical perspective method in real-time during the mining process. The system uses two types of observation data for constrained inversion imaging, improving the imaging resolution of low resistance anomalous bodies. A two-stage amplification and power frequency filtering circuit is designed to configure different sampling timing, sampling frequency, and digital filters during the collection of electrical profile and perspective data. It will suppress the interference of large-scale electrical equipment on electrical response signals. The performance test results show that the high-resolution electrical monitoring system for mining can effectively distinguish 1 µV target signal in noisy environments. The power frequency suppression ratio is not less than 35 dB and 80 dB in the electric perspective mode and electric profile mode, respectively. The results of the physical simulation test in the water tank indicate that the system can effectively distinguish low resistance anomalous bodies with a size of approximately 10 m3 at a depth of 60 meters below the floor when the working face is inclined towards about 300 meters. The test and experimental results have verified that the system has strong power frequency interference and random interference suppression capabilities. The system can obtain reliable and effective data under limited observation space and strong interference conditions in coal mines, improving the imaging resolution of abnormal bodies in inversion results.
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