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With the increase of mine mining intensity, the scope of goaf continues to expand, a large amount of coal remains in goaf, and the spontaneous combustion fire of coal is particularly serious. In addition, the spontaneous combustion of coal under the condition of gas mining is not clear. At once, spontaneous combustion can induce gas explosion, resulting in the waste of manpower and material resources, bringing hidden dangers to the mine safety production. In order to prevent and control the fire caused by spontaneous combustion of left coal under the condition of gas mining, in this paper by means of laboratory test, field measurement, and numerical simulation, the law of spontaneous combustion of residual coal under gas mining is studied. The index gas of coal spontaneous combustion was determined by temperature-programmed experimental device. Secondly, the distribution of the stope working face, goaf, and O2 is discussed. It is of great significance to study the spontaneous combustion rule of three belts in goaf under acid leaching condition and then to discuss the best position of injection idling opening and put forward targeted precontrol measures, which is of great significance to guarantee the safety of mine production. The results show that CO begins to appear when the temperature rises to 40 °C, and its concentration increases exponentially with the increase of coal temperature, which can reflect the degree of coal oxidation in goaf. Therefore, CO should be selected as the indicator gas in the working face. Under the influence of negative drainage pressure, the dangerous area will be enlarged. The optimal drainage volume of high drainage roadway is 90 m3/min, and the optimal air intake volume of working face is 1400 m3/min. The area 0–34 m away from the working face is scattered zone, 34–135 m away is spontaneous combustion zone, and 135 m away is asphyxiation zone. When the position of the idler is 50 m behind the working face, the reduction of the oxidation zone is the largest.

To study the synergistic stabilization mechanism of SiO2 nanoparticles and anionic surfactants during foam fracturing, inorganic SiO2 nanoparticles and sodium dodecyl sulfate (SDS) were used as a foam stabilizer and foaming agent, respectively, to prepare foam fluids. Foam stability was analyzed by evaluating the foam volume, half-life, and morphology. The synergistic stabilization mechanism of SDS and SiO2 nanoparticles was studied by measuring and analyzing the surface tension, contact angle, and bubble diameter. The results indicated that, at a suitable SDS concentration, the surface activity of the nanoparticles can be altered to enhance the adsorption of SiO2 nanoparticles at the gas–liquid interface and, consequently, improve foam stability. However, excess SDS caused a decrease in foam stability. Upon increasing the SDS concentration, the contact angle between the SiO2 nanoparticles and water decreased gradually, and the SiO2 nanoparticles became increasingly hydrophilic. The average bubble diameter of the SiO2–SDS foam systems decreases with the increase in time, and the foam system with the smaller change trend of the bubble diameter is more stable. Moreover, with the increase in time, the nanoparticles adsorbed by the ruptured bubbles are transferred to the surrounding of the bubbles that are not ruptured, increasing their liquid film thickness and improving the stability of the foam system. These results provide an experimental basis for the application of the nanoparticle in foam stabilization during coal seam fracturing.