陕西火石咀矿煤层采用综合机械化放顶煤开采，煤层具有自燃倾向，ZF8709工作面停采时间较长，为避免发生采空区遗煤自然发火，开展了防灭火技术研究。采用CFZ20型自动负压采样器对采空区中的气体浓度进行分析，以氧气浓度18%和8%作为分界线，确定了散热带、自燃带和窒熄带的分布范围。普瑞特材料具有膨胀倍数高，扩散性能好的优点，是一种理想的防灭火材料。为防止煤层自燃，采用工作面全长架后采空区封堵+两端头预防性注浆+持续注氮的防灭火技术。现场监测表明，停采期间CO浓度稳定在0.001 0% 以下，未监测到发火征兆。

The coal seam of Huoshizui Coal Mine in Shaanxi Province adopts comprehensive mechanized top coal caving mining, and the coal seam has the tendency of spontaneous combustion. ZF8709 working face has a long time to stop mining. In order to avoid spontaneous combustion of residual coal in goaf, the research on fire prevention and extinguishing technology was carried out. The CFZ20 automatic negative pressure sampler was used to analyze the gas concentration in the goaf. The oxygen concentration of 18 % and 8 % was used as the dividing line to determine the distribution range of the heat dissipation zone, the spontaneous combustion zone and the suffocation zone. Pret material is an ideal fire-fighting material with the advantages of high expansion ratio and good diffusion performance. In order to prevent coal seam spontaneous combustion, the fire prevention and extinguishing technology of goaf sealing after full-length frame of working face + preventive grouting at both ends + continuous nitrogen injection is adopted. On-site monitoring showed that the CO concentration was stable below 0.0010 % during the shutdown period, and no signs of ignition were monitored.