The Role of Organic Sulfur in the Formation of Methane Emissions on the Spontaneous Combustion of Coal

Spontaneous combustion of coal is a phenomenon that often occurs in open coal mining activities, especially strip mining and open pit mining systems which are detrimental to mining companies, the economy, the environment, and society. This phenomenon causes coal mining activities to contribute to CH4 gas emissions in global warming by 11% of total global emission. The purpose of this study was to analyze the role of organic sulfur in the formation of CH4 gas emissions in the spontaneous combustion of coal in the TAL area. The approach is based on a literature review and field survey. The literature review was intended to examine the influence of geological factors, maceral analysis, and depositional environment on the rank and form of coal sulfur, while the field survey was conducted by measuring CH4 gas emissions in 36 samples of spontaneous combustion hotspots. Literature review shows that coal in the TAL area belongs to low rank (sub-bituminous/sub-bituminous B) which has high organic sulfur content in the form of thiother bonds (C-S), especially carbon disulfide (CS2). The average CH4 emission measurement in the field is 6,989 mg/m3, which is still within the limits set by other researchers, between 3,700-34,098 mg/m3. The role of organic sulfur from C-S bonds especially CS2 in the formation of CH4 gas emissions, is very dominant at 93.10% or 6,507 mg/m3 of the total coal sulfur in the TAL area. The emission of CH4 gas in the spontaneous combustion of coal is strongly influenced by geological factors, maceral analysis, and the depositional environment related to the rank and form of coal sulfur. Further, detailed, and comprehensive research on the form of organic sulfur needs to be carried out to mitigate CH4 gas emissions in the spontaneous combustion of coal in the TAL area.