Mechanism of using magnetic susceptibility to predict hydrogen sulfide abnormal zone in coalfield

The abnormal gush of hydrogen sulfide threatens the safety of mining. At present, there is no method and index to predict the enrichment area of hydrogen sulfide. Two coal samples (with or without magnesium sulfate added) were used in pyrolysis experiment, the temperature of two samples at 300℃ is the critical temperature for the generation of hydrogen sulfide gas, and it is also the temperature at which the magnetic susceptibility of the samples increases rapidly, the production of hydrogen sulfide is positively correlated with the high magnetic susceptibility of the sample during coal pyrolysis, therefore the zones with high magnetic susceptibility may be the rich area of hydrogen sulfide in coal field, and the magnetic susceptibility may be used to delineate the abnormal area of hydrogen sulfide. The magnetic susceptibility of coal at 51–138 (unit: 10^− 7 SI) may be used to critical value for predicting abnormal zone of hydrogen sulfide in coal bed.