Impact of Boundary Conditions on the Temperature Rise and Multi-Field Dynamics of Coal Mine Goaf

Coal spontaneous combustion (CSC) poses a significant safety risk in mining, particularly in the goaf where heat accumulation can lead to self-ignition. This study investigates the impact of working condition boundary conditions on the temperature rise and multi-field dynamics of the underground coal mine goaf located in the Hujierte mining area, northwestern China. Coal samples from adjacent working faces of the 2–1 coal seam were analyzed under varying airflow and oxygen conditions using thermogravimetric (TG) and differential scanning calorimetry (DSC) methods. The results show that increased airflow enhances heat dissipation and reduces the low-temperature oxidation rate, while higher oxygen concentrations accelerate oxidation and eventually lead to the decrease of characteristic temperatures due to enhanced oxygen adsorption. The study also found that increased leakage leads to a backward shift in the airflow velocity field, concentrating high-temperature zones in the return airway, especially at depths of 3–30 m. These findings highlight that spontaneous combustion risks are highest in low-flow, high-gradient regions, particularly in areas with high leakage. The results are crucial for identifying high-risk areas and developing effective prevention strategies for coal spontaneous combustion in mining operations.