Investigation of the Role of Fire Retardants in Preventing Spontaneous Heating of Coal and Controlling Coal Mine Fires

Mine fire is a major problem for the Indian coal mining industry and exists since beginning of the mining. A huge amount of the prime coking coal reserves of different coalfields are blocked due to existence of fire and thus cannot be extracted without extinguishing it. Many approaches have been attempted in this direction to minimize this socio-technological problem. Use of chemical retardants to inhibit smouldering combustion phenomenon is an important method, which can be adopted to prevent or delay its occurrences. In this situation, it may sometimes be necessary to use fire retardants for reducing the intensity of fire so that the coal production will not be hampered. This paper presents the impact of chemical additives on coal oxidation process, studied from the mechanistic perspective aiming to search effective retardant materials to prevent and control coal self-heating phenomenon. A numbers of chemicals and combinations along with coal, which are moderately prone to smouldering combustion, were studied to determine its efficacy to prevent and combat it. In the process CPT, IPT and DSC study of coal samples and chemicals were observed. Based on the results, suitable retardants were selected and mixed with coal samples. The mixtures were further analysed for above properties. Finally, the best suitable combination of inhibitors were determined and applied in the field, which gave desired results.