Prevention and Control of Spontaneous Combustion of Residual Coal in Goaf of a Coal Mine

The No.110 fully-mechanized top‑coal caving face of the mine mines the No.10 and No.11 coal seams, with a dirt band between them. The total thickness of the two coal seams is about 6 meters. The coal seams are prone to spontaneous combustion, belonging to Class Ⅱ spontaneous combustion coal seams with a spontaneous combustion period of 80 days. The mine is a low‑gas mine with low gas emission.
The face adopts the fully-mechanized retreating top-coal caving mining method, and the roof is managed by the full caving method. Two roadways are arranged, with the belt gateway used as the return airway. Due to the shallow burial depth of the face and the existence of small kiln goafs in the overlying strata, positive pressure ventilation is continuously adopted to avoid external air leakage and gas intrusion.
Abnormal CO was detected at the upper corner of the No.110 face, and the CO concentration rose to approximately 120 ppm. It was analyzed that the residual coal in the adjacent No.108 goaf experienced oxidation and spontaneous combustion due to the large amount of residual coal and the influence of air leakage. The face was subsequently shut down for the Spring Festival holiday. To prevent intensified oxidation of residual coal in the goaf, which would pose a serious threat to safe production, it was urgent to take corresponding prevention and control measures.
In view of the above situation, Purite Special Mine Fire Extinguishing Liquid (JTF-Ⅰ) and its supporting application equipment developed by our company were applied. Grouting boreholes were arranged at the corners and between supports of the No.110 face to implement the material. As a result, the residual coal in the goaf was effectively insulated from oxygen and cooled, preventing further oxidation and spread. The CO concentration at the return corner and between supports of the face decreased steadily, ensuring the subsequent safe and rapid advancement of the No.110 face and the safe production of the mine.