Sub-bituminous coal C that is stored for extended periods in stockpile can lead to the occurrence of self-heating. This self-heating is a result of oxidation reactions involving coal, oxygen, and heat at low temperatures. Self-heating contributes to environmental quality decline due to the release of greenhouse gases, such as methane emissions, which significantly impact global warming. The purpose of this study is to explore the characteristics of self-heating, which is a stage in spontaneous combustion linked to the generation of methane emissions in coal piles with a calorific value below 6,100 kkal/kg in stockpiles. The research methodology combines field data collection with literature review focusing on variables like temperature, time, and methane emissions, with data processing carried out through statistical analysis using Pearson correlation tests and linear regression. The characteristics of self-heating are studied by examining the relationships between time and temperature, temperature and methane emissions, as well as time and methane emissions. Research findings suggest that the self-heating characteristics in the study area are still at a latent stage, which can be divided into two categories: the traditional latent stage and the preparation latent stage. This stage has a temperature range of 43.98 - 54.19 °C and 58.84 - 61.27 °C, a time span of 32 - 46 minutes and 49 - 52 minutes, along with methane emissions that fall between 3192 - 17319 ppm and 17408 - 20575 ppm, respectively. The emissions flux for temperature and methane during the traditional latent and preparation stage in the research area measures 44.14 °C/hour, 1371.55 ppm/°C, 60544.20 ppm/hour, and 9.20 °C/hour, 6884.78 ppm/°C, 63340.00 ppm/hour, respectively. This situation indicates that if self-heating is not properly managed, it can lead to an increase in methane emissions, negatively impacting global warming. Therefore, it is essential to implement preventive measures to mitigate methane emissions from self-heating by adjusting dimensions and installing temperature sensors on stockpiles.