In recent years, the mining technology of ″roof cutting and pressure releasing″ has appeared in China. It is called China’s third mining revolution. The technology of ″roof cutting and pressure releasing″ has changed the traditional working face ventilation system and the boundary conditions of a goaf. The law of air leakage in the goaf has changed, resulting in changes in the distributions of CO and other disaster gases. In order to ensure the promotion of this advanced mining technology safely, research on the distributions of CO and other disaster gases is very necessary. By installing CO sensors in the air intake lanes, gob-side entry retaining, and goaf, the distribution of CO in the goaf during the advancement of the working face under the ″roof cutting and pressure releasing″ mining method is studied. The concentration of CO in the upper corners of the working face under the traditional mining method and the ″roof cutting and pressure releasing″ mining method was compared and analyzed. The results show that the CO in the experimental working face mainly comes from the oxidation of the residual coal; after analysis, the CO concentration in the goaf is divided into three areas: the slowly increasing area, sharply increasing area, and attenuation area; the CO concentration in the upper corner of the working face of Y-shaped ventilation with ″roof cutting and pressure releasing″ mining is much lower than that in the upper corner of the working face of U-shaped ventilation in the traditional mining; In order to prevent the oxidation and heating of the residual coal in the goaf to produce CO, comprehensive prevention measures for CO escape in the goaf have been adopted. After actual production verification, the prevention and control measures show good effects to ensure the safe and effective production of the working face.

Long-flame coal is a bituminous coal with the lowest metamorphic degree, accounting for 16.1% of China’s coal reserves. With increases in mining depths and intensities, mine gas disasters related to the mining of long-flame coal are becoming increasingly serious. Therefore, the exploration of the effect of moisture on the adsorption of methane in coal can provide support for popularizing the application of hydraulic measures in long-flame coal mining areas. In this paper, a molecular structure model of long-flame coal was established by molecular dynamics and the Monte Carlo method. The adsorption characteristics of methane in long-flame coal structures under different pressures were simulated, and the effects of different amounts of water on the methane adsorption and adsorption heat were explored. The results show that, under the same adsorption equilibrium pressure, the methane adsorption rate decreases with increasing water content, and with increasing adsorption equilibrium pressure, the adsorption capacity of methane increases gradually; this increasing trend is in agreement with the Langmuir equation. The water adsorption of coal is greater than the methane adsorption of coal. With the increase in the number of water molecules, when coal-based molecules adsorb methane and then adsorb water molecules, the adsorption heat of methane is reduced, and the desorption of methane molecules is promoted.

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The airflow exchange between a mining face and a coal mine goaf can cause gas transfinite and spontaneous coal combustion disasters, threatening coal mining. Studying the characteristics of airflow movement in a goaf forms the basis to prevent airflow exchange for coal mining safety. Different from the traditional longwall mining mode, the roof-cutting and pressure-releasing mining mode shows new roof collapse characteristics and a ventilation system, which lead to obvious changes in the characteristics of airflow movements in coal mine goafs. To study the differences in airflow movement characteristics and the airflow disturbance influence area in a coal mine goaf between these two mining modes, the airflow movements in different goafs are compared using a numerical simulation method based on the measured parameters of the 1201 mining face in the Halagou Coal Mine, China. The results show that the airflow disturbance area in the goaf under the traditional longwall mining mode is a “η” type. Along the inclination direction of the mining face, two main exchange areas for the airflow are located in the 0–5 and 15–45 m sections, respectively. The airflow disturbance area in the goaf under the roof-cutting and pressure-releasing mining mode is a “hump” type, and there are six main exchange areas in the goaf under the roof-cutting and pressure-releasing mining mode. Along the inclination direction of the mining face, three exchange areas are located in the 0–25, 255–305, and 305–320 m sections, respectively. Along the strike direction, three exchange areas are located in the 5–25, 25–35, and 35–65 m sections, respectively. Based on the research results, sealing measures are taken to slow and eliminate airflow exchange in the goaf under the roof-cutting and pressure-releasing mining mode, and this provides theoretical guidance for safe coal mining.

The influence of the depressurization rate on coalbed methane desorption and percolation was studied using physical experiment and numerical simulation. First, low-field nuclear magnetic resonance technology provided a new approach to conduct desorption experiments with different depressurization schemes and obtain the compressibility ( C f ) of coal samples. Then, the productivity calculation of different depressurization schemes was carried out via numerical simulation. The results showed that the first-slow-then-fast (FSTF) depressurization scheme had the highest desorption efficiency (94%), followed by one-stop desorption (85%), first-fast-then-slow desorption (79%), and uniform depressurization desorption (61%). T 2 cutoff values and the corresponding compressibility were obtained by the saturation–centrifugation method and spectral morphology method, and a high-precision permeability expression for dynamic evaluation of numerical simulation was established by the historical production data fitting approach. Through numerical simulation, high production efficiency can be achieved using depressurization rates of medium (15 kPa/d) and FSTF schemes (8 & 50 kPa/d), and depressurization funnel expansion in the single-phase water flow stage plays a decisive role in stable and high-yield production in the later stage. Thus, the FSTF pressure reduction strategy could be advocated to promote gas production. Slow depressurization should be applied in ineffective desorption and the slow desorption stage for saturated coal seam or single-phase flow stage for undersaturated coal seam, given the higher single-phase water permeability. During the rapid and sensitive desorption stage, rapid depressurization is recommended because of large desorption capacity and low water phase permeability. This paper provides a possibility for the optimization of coalbed methane field production management.