146 / 2023-06-30 10:06:00

Application of thickened slurry to prevent and control coal spontaneous combustion in overlaying goaf - A case study in Anyuan coal mine,China

Coal spontaneous combustion,Thickened slurry,Dangerous zone of coal spontaneous combustion,Thickened slurry fire prevention and extinguishing technology,Suspension performance

The spontaneous combustion of coal in goaf seriously threatens the safety of coal mine production. In response to the problem of excessive residual coal and severe air leakage in the overlying goaf, which makes it difficult to determine and prevent the dangerous zone of coal spontaneous combustion, a new type of thickened slurry for preventing coal spontaneous combustion in overlying goaf was prepared based on polymer material , surfactant, loess and water. Taking the 378 working face of Anyuan coal mine as the research object,the dangerous zone of coal spontaneous combustion in the overlying goaf of 378 working face was determined through numerical simulation, and thickened slurry fire prevention and extinguishing technology was put forward. The results showed that the thickened slurry was pseudoplastic non-Newtonian fluid. When the ratio of water to soil was 8:1 and the concentration of thickener was 0.3%, the thickened slurry had better suspension performance, minimum yield stress and better fluidity. By superimposing the oxidation zone of air leakage velocity and oxidation zone of oxygen concentration, it was determined that the location of dangerous zone of coal spontaneous combustion was located in the open-off cut of 378 working face in the first layer and the overlying goaf of the return air roadway in the second layer. After using the thickened slurry fire prevention and extinguishing technology , the CO concentration in the overlying gob decreased, and even dropped to 0 in the later stage. The O₂ concentration in the sealing of the return air roadway decreased significantly, the pressure difference was in a stable state, and the outlet temperature of each borehole was lower than 25℃, which proved that the thickened slurry fire prevention and extinguishing technology had a good effect on coal spontaneous combustion in the overlying gob.