Self-combustion is very common in coal-fields of northern China

which takes great losses of coal resources and impairs the ecological environment in China every year.The border of self-combustion zone should be determined in order to control and monitor the self-combustion of coal-field.The coal layers would be magnetized after self-combustion.Based on this theory

we have determined the border of coal combustion with high-precision magnetic measurement in a coalfield in northwest of China.The equipment used is IGS-2/MP-4

with parameters being totally magnetic-ΔT.To determine the border precisely we propose a model of "finite plate-shaped body of inclined magnetization".The exposure of drill holes show that the border of self-combustion can be reasonably determined by high-precision magnetic measurement.