The Australian underground coal mining industry has increasingly relied on goaf gas drainage to manage methane levels and reduce gas emissions in recent years. As mining operations go deeper and produce more gas, the spacing between vertical goaf gas drainage boreholes has narrowed, and suction pressure has increased. While this proactive goaf gas drainage design enhances borehole drainage efficiency, it also alters goaf pressure distribution and gas flow patterns. This alteration leads to increased ventilation air leakage, elevating the risk of gas explosions and spontaneous combustion, which threatens mine safety. This study analyses field goaf gas drainage data from various Australian coal mines to identify the general goaf gas profiles (O2, CH4, CO, and CO2) and develop a goaf conceptual model under the impact of goaf gas drainage. Additionally, it involves developing Computational Fluid Dynamics (CFD) models to understand goaf gas flow patterns with operating vertical boreholes, calibrated using back analysis results. The simulation results from the calibrated CFD model align well with the goaf conceptual model based on field gas drainage data. The study reveals that ventilation air leakage from the face flows along the maingate side goaf, travels through high-permeability channels to the tailgate side and is extracted by vertical boreholes. These findings help engineers visualise airflow pathways within the inaccessible longwall goaf under intensive gas drainage conditions. Moreover, this study uses CFD modelling to compare goaf atmospheres, gas explosion risks, and spontaneous combustion risks across various scenarios. It emphasises the sensitivity of different natural characteristics, including goaf permeability distribution, gas emission rate, and gas drainage parameters. The findings guide operators in enhancing goaf gas drainage by integrating field data analysis with numerical simulations. By prioritising safety in mining operations and reducing environmental impact through effective gas emission control, this study advances mining practices and promotes environmental sustainability.