When a longwall face approaches the finish-off line, 1 month is normally required to relocate the longwall equipment and seal the longwall panel, during which time the goaf gas atmosphere changes and the risk of spontaneous combustion and gas explosion considerably increases. To minimise the occurrence of these hazards, an improved insight into gas flow dynamics within the longwall panel is essential during the panel sealing-off process. Based on mining conditions of an Australian underground coal mine, three-dimensional computational models were developed and calibrated with onsite gas monitoring data, allowing for evaluating ventilation arrangements and understanding methane dispersion in the longwall workings during the six-stage panel sealing-off process with confidence. The simulation results indicate that nitrogen should be injected on the travel road side at a distance of 120 m behind the longwall face at a rate of 0.75 m³/s and the rear of the travel road should be tightly sealed at the final sealing-off stage, resulting in oxygen levels lowering than 5% in the longwall workings and producing desired panel sealing-off performance. In addition, gas sensors should be employed and positioned at the appropriate locations to reliably monitor goaf atmosphere change. This study sheds improved insights into evaluating ventilation arrangements and understanding gas flow dynamics during the panel sealing-off process and provides critical knowledge of effective proactive goaf inertisation strategies, thus minimising the risk of spontaneous heating and gas explosion and reducing environmental pollution induced by these hazards.

当长壁工作面接近终点线时，通常需要1个月的时间来搬迁长壁设备并密封长壁面板，在此期间采空区瓦斯气氛发生变化，自燃和瓦斯爆炸的风险大大增加。为了最大限度地减少这些危险的发生，在面板密封过程中，必须深入了解长壁面板内的气流动力学。根据澳大利亚地下煤矿的开采条件，开发了三维计算模型并利用现场瓦斯监测数据进行了校准，可以评估通风布置并了解长壁工作区在六阶段面板封堵过程中的甲烷扩散情况信心。模拟结果表明，应在长壁工作面后120 m处的行驶路侧以0.75 m ³ /s的速度注入氮气，最终封堵时应将行驶路后部密封严实。阶段，导致长壁作业中的氧气含量低于 5%，并产生所需的面板密封性能。此外，应采用气体传感器并将其放置在适当的位置，以可靠地监测采空区大气变化。这项研究为评估通风布置和了解面板密封过程中的气流动力学提供了更好的见解，并提供了有效主动采空区惰化策略的关键知识，从而最大限度地减少自热和瓦斯爆炸的风险，并减少这些危害引起的环境污染。