The Influence of the Sample Preparation on the Result of Coal Propensity to Spontaneous Combustion in the High-temperature Adiabatic Method

The liability of coal to spontaneous combustion is the principal cause of mine fires. Spontaneouscombustion is one of the main threats in Polish and Vietnamese coal mines. The article presents an analysisof the spontaneous combustion of coal in mines of both countries. It is related to the natural prone of coalto spontaneous heating and consequently to its self-ignition. Despite the relevant recognition of themethods of preventing this threat, in mines, spontaneous combustion occurs during the exploitation ofcoal seams with low and very high self-ignition tendency. Apart from the technical factors related to thedesign of coal seam mining, the properties of coal have a significant impact on the occurrence ofspontaneous combustion. Their correct recognition is essential to the precautions against spontaneouscombustion for minimalizing the risk of a mine fire. Therefore, it is necessary to study the factorsinfluencing the propensity of coal to spontaneous heating. A review of the methods used to determine thepropensity of coal to spontaneous combustion is presented in the article. Based on the high-temperaturemethod of determining the propensity of coals to spontaneous combustion, the influence of selectedfactors related to samples' preparation for testing on the determination result was investigated. Theinfluence of the fractional decomposition and the moisture content in the prepared samples on thedetermination result was demonstrated. The presented research results may improve research proceduresfor determining the propensity of coal to spontaneous combustion.

Effect of Inhibitor in Suppressing Spontaneous Heating of Coal

Spontaneous combustion of coal is a natural phenomenon responsible for the burning of thousands of tonnes of coal every year. Normally, when Indian coal gets exposed to air, it catches fire within 9 to 12 months and the application of inhibitors helps in preserving the coal by enhancing its time period (Incubation period). They have the capacity of retarding the spontaneous heating of coal by forming a protective layer around it. This paper deals with four inhibitors and its retardation capacity to spontaneous heating is laid down by experimental investigation. Crossing Point Temperature (C.P.T) analysis and Flammability Temperature analysis (F.T) are the prime method in determining its retardation effect. Coal samples from Mahanadi Coalfield Limited (MCL) were prepared and used for experimentation. Proximate analysis is used to study the composition of coal. The prepared coal sample is treated with inhibitors at three different proportions of 5%, 10% and 15% by wt. Considering the economic and safety application for miner and mining industry, the maximum retardation capacity of an inhibitor at particular percentage is been shown in this paper.