Transient Electromagnetic Response Characteristics of Large Iron Interference in Mine

To improve the data acquisition quality from the source under circumstance of interferences by using mine transient electromagnetic method, we adopted 3D finite element numerical simulation and field tests to analyze the responsing characteristics and variation laws of the induced electromagnetic field under different levels of interference from large iron, summarized the measure to weaken corresponding interference. The study results showed that: under condition of close range and strong interference of large iron like roadheader, the induced electromagnetic field of strata would produce non-uniform changes in spatial form and time distribution; the interference responses were sensitive to distance condition, the detecting effect would improve when the distance between the large iron and the detecting coil is beyond 4 m.