Abstract:Yizhao coal well is an exceptional large concealed coalfield in Yili basin. There is a large burning area in the southeastern coalfield formed by the surface coalseam spontaneous combustion, and the ground highprecision magnetic survey has been used to detect and delineate the deep concealed burning area. After the coalseam spontaneous combustion, the roof and the floor of the strata and the dirt band will be formed to the burnt rocks due to thermal remanence phenomenon under high temperature, and the remanence will cause a certain intensity of magnetic anomaly on the ground. All the above mentioned elements are geophysical premises to carry out magnetic survey work in this area. In this paper, theoretical basis, data collection, data processing and interpretation, interpretation accuracy of magnetic survey have been discussed in detail. The survey area is about 5.7km2, 62 measuring lines have been set and data collection has been carried out by line distance of 100m and dot pitch of 20m, and the ΔT data is dealt with geomagnetic pole processing and upward continuation. According to the qualitative and quantitative interpretation of anomalies by the ΔT plane isoline graph, ΔT section plan and ΔT upward continuation plane isoline graph, 3 magnetic anomalies have been determined. The strength increases from west to east with the depth of the brunt rock becoming lighter and the thickness becoming larger, all the above shows that metamorphism in the west part is more severe. It is inferred that the anomalies are mainly caused by the burnt rock formed by 5 coalseam spontaneous combustion. The results are basically consistent by using the method of twodimensional seismic exploration.
