How to prevent coal from spontaneous combustion?

Coal itself has a tendency to spontaneous combustion, that is, it has low-temperature oxidation ability, which is an intrinsic factor of spontaneous combustion, depending on the physical and chemical properties of coal itself and the composition of coal. Different grades of coal have different coal and rock compositions and different self-ignition properties. Lignite is more spontaneously ignitable than bituminous coal; in bituminous coal, long-flame coal and gas coal have the strongest self-ignition; poor coal and anthracite have poor self-ignitability; In the same grade of coal, the more sulfur, the easier it is to spontaneously ignite. Therefore, Article 228 of the “Safety Regulations for Coal Mines” stipulates that the spontaneous combustion tendency of coal is divided into three categories: easy to spontaneous combustion, spontaneous combustion, and not easy to spontaneous combustion.

"Water and fire are incompatible", the coal contains more water and is not easy to spontaneously ignite. However, after the self-igniting coal loses moisture, the risk of spontaneous combustion increases. Therefore, the surface coal pile is prone to spontaneous combustion after rain and snow leakage and evaporation; the underground water floods the self-ignition fire zone, and after the production is resumed, it is more likely to spontaneously ignite because the coal passes through After washing, the coal surface is more susceptible to oxidation.

The geological conditions of coal seams have a great impact on coal spontaneous combustion. The thicker the coal seam, the larger the angle of inclination, the greater the risk of spontaneous ignition of the coal. Because in the thick coal seam and steeply inclined coal seam, the recovery rate is low, and more coal is lost; the coal pillar in the mining area is easily broken after being pressed, the sealing of the goaf is not tight, and the air leakage is large, which creates conditions for spontaneous combustion of coal. At the same time, in the fault, fold and fracture zone, coal is prone to spontaneous combustion.

For mines with a strong tendency to spontaneous combustion of coal, the main roadway should be placed in the rock formation to reduce the coal pillars and avoid excessive coal seam cutting and exposure to the air. At the same time, appropriate coal mining methods should be selected to improve the recovery rate and reduce coal loss. Close the goaf in time to reduce or avoid air leakage into the goaf.