Application of Microtremor Survey Technology in a Coal Mine Goaf

Goafs are one of the main factors that endanger the safety of mining areas, leading to roadway collapse, land subsidence and other problems. Determining how to detect goafs accurately and efficiently is an important issue faced in engineering geophysical exploration research. Microtremor survey technology, used in geophysical exploration, has been developed in recent years. It has the advantages of low cost, flexible construction, low topographic impact and high efficiency. In this paper, microtremor survey technology was applied to the detection of a coal mine goaf. In the known goaf area of the Taiyuan Nanling Coal Mine, a linear observation array was arranged to conduct rolling acquisition, observe the microtremor signal records of the natural field and use the extended spatial autocorrelation method to extract the dispersion curve. Through the inversion of the extracted dispersion curve, the apparent shear wave velocity profile of the underground medium clearly showed the location of the goaf. It was roughly consistent with the goaf data obtained from the mine. The detection results reflect the advantages of micromotion exploration. The goaf of Coal Seam #2 and its affected area appear to be due to an obvious low-speed phenomenon. The boundary of the apparent shear wave velocity profile of micromotion detection was basically consistent with the boundary of the goaf, indicating that micromotion exploration technology has good technical advantages and application prospects in the detection of coal mine goafs. The rolling acquisition method of linear arrays can be used to ensure accurate detection, improve exploration efficiency and save on exploration costs.