Fine detection of collapse columns based on controlled source audio-frequency magnetotelluric method

Abstract

Taking Huangyuchuan Coal Mine as the research background, aiming at the problem that the suspected collapse column found in the geological exploration of the mining area has not yet been clear about its development range and water content, based on the geological and geophysical characteristics of the suspected collapse column, this paper adopts controlled source audio magnetotelluric method(CSAMT) to finely investigate the suspected collapse columns and applies the 2D Occam inversion method to finely process the measured data and analyze the electrical response characteristics of the geological anomalies in combination with geological data. The electrical anomaly has obvious characteristics of low resistance electrical response, and finally delineated the geological anomaly and inferred that the anomaly is caused by a water-bearing collapse column. The collapse column is mainly developed in the 6# upper coal seam near the Ordovician limestone, and the diameter is about 30 m at the corresponding 6# coal seam position(depth 395 m), and the diameter increases to the deep. Subsequent underground drilling verified the accuracy of the CSAMT exploration results.

Keywords

• controlled source audio magnetotelluric method
• collapse column
• fine exploration
• occam inversion
• water abundance