Detecting Coal Self-heating by Condensation Aerosol Content in the Air

The issues under consideration are spontaneous combustion of coal and the danger of endogenous fires for mining enterprises. The ways of detecting the hotbeds of spontaneous combustion which allow to increase the safety of mining works and to reduce economic damage from endogenous fires are analyzed. The temperature control is demonstrated to be ineffective due to thermal insulation properties of coal, and the gas analysis method - insufficient for detecting the initial stages of coal self-heating. It is proposed to detect the self-heating of coal by the condensation aerosol content formed at the cooling of the air heated in the source. The calculations of the condensation aerosol content in the air depending on the temperature of the coal self-heating spot are given. Dependences determining the temperature of coal self-heating spot, depending on the condensation aerosol content in the air passing through the coal have been obtained. Various sorbents for measuring condensation aerosol content in the air have been studied. The most effective sorbent of water vapor and condensation aerosol is macro-porous silica gel. A device detecting coal self-heating in mines, mine dumps, and coal storages has been developed. Tests in mine conditions proved the effectiveness of the method for detecting coal self-heating.