The complex environment such as high ground temperature faced by deep coal resource mining aggravates the risk of spontaneous combustion of residual coal in gob, and the catalysis of intrinsic metal elements in coal is the key internal cause to accelerate its low-temperature oxidation and heat release. The existing coal spontaneous combustion inhibition materials rely on liquid phase physical barrier, which is difficult to adapt to the long-term inhibition requirements of deep high-temperature environment. In this study, a new eutectic inhibitor (DEI) was developed by using eutectic solvent formed by citric acid and proline as liquid phase carrier, vitamin C and propyl gallate. Lignite, gas coal, coking coal, and anthracite coal samples with four different metamorphic degrees were selected. The contact angle test, electrostatic potential energy analysis, ICP element detection, and simultaneous thermal analysis (TG-DSC) were used to systematically investigate the wetting behavior, metal element dissolution law, and exothermic inhibition characteristics of DEI on different coal samples. The results show that DEI achieves efficient wetting of coal by means of the strong electrostatic attraction between the high positive potential region of the molecule and the negative functional groups on the coal surface. Among them, the wetting effect on DHLC lignite is the best, and the contact angle decreases from 106.74 degrees to 49.51 degrees within 40 s. The catalytic oxidation of Fe, Ca, and other metal ions in coal can be efficiently dissolved by chelation, and the leaching amount is increased from 6.471 mg/L and 27.343 mg/L to 18.275 mg/L and 75.962 mg/L, respectively. At the same time, the surface reconstruction of Al element is realized to block the active site. After the removal of metal elements by DEI, the characteristic temperature of the coal body increases significantly, the heat release decreases, and the heat release in the combustion stage is greatly reduced by 170.88 similar to 540.5 J.g(-1). This study reveals the inhibition mechanism of deep eutectic inhibitors from the perspective of micro-element dissolution, and provides theoretical and technical support for the long-term inhibition of spontaneous combustion of residual coal in deep coal mine gob.

To enhance the performance of coal mine gas extraction sealing materials, graphene oxide (GO) was synthesized via the Hummers method and blended with Polyvinyl Alcohol (PVA) fibers and ordinary Portland cement to prepare GO-PVA composite cementitious grouting materials. Optimal performance was obtained with 0.25% water-reducing agent, 0.03% GO, 0.1% PVA fibers, and 8% expansive agent. After 3 days of curing, the compressive strength of the composite cement-based sealing material reached 43.23 MPa, while that of the ordinary cement sealing material was only 30.16 MPa, which was 43.33% higher than that of the latter. After 28 days of curing, the compressive strength of the composite sealing cement-based material was further increased to 62.73 MPa, compared with 45.56 MPa of the ordinary cement sealing material, and the composite material was still 37.69% higher. The consolidated body formed by composite cementitious sealing material and coal (hereinafter referred to as group (A) and the consolidated body formed by ordinary cementitious sealing material and coal (hereinafter referred to as group (B) are compared in this study. When the confining pressure is 2 MPa and the axial pressure is 8 MPa, the maximum permeability of group A coal sample is 6.551 mD, while the maximum permeability of group B coal sample is 5.152 mD, when the confining pressure increases to 2.5 MPa and the axial pressure remains at 8 MPa, the maximum permeability of group A coal decreases to 3.157 mD, and the maximum permeability of group B coal decreases to 1.129 mD. The composite material markedly increases the compressive strength of the matrix and exhibits excellent diffusivity in coal seams. After consolidation it alters the coal microstructure, thereby significantly reducing permeability. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analyses were employed to examine the microstructure of the composite cement-based grouting material. The results indicate that the GO-PVA composite enhances the ion migration efficiency. Higher migration efficiency accelerates the hydration reaction rate, promoting more complete reactions, and improved the overall performance of the cement matrix by promoting a denser structure.

Spontaneous combustion in coal mine goafs is one of the main risks during mining. The effectiveness of existing coal spontaneous combustion prevention technologies is influenced by fluid flow resistance loss in goaf porous media. This study proposes a sphere-cylinder assembly (SCA) as a fundamental unit for investigating flow loss in goaf porous media. The Hagen-Poiseuille equation, combined with the capillary model and the theory of average hydraulic radius, was used to derive expressions for viscous and inertial pressure losses, leading to the development of the SCA pressure drop prediction model (S-C model). An experimental setup was constructed to study the flow characteristics of porous media and validate the S-C model. Results indicate that the S-C model's prediction errors are mostly below 20%, outperforming the Ergun equation. Flow states within the porous media were delineated based on pressure drop and Reynolds number relationships, establishing ranges for Darcy flow, transition flow, and non-Darcy flow. Analysis of the friction factor f and Reynolds number Re further confirmed the accuracy of the flow state classification. The empirical f formula showed significant errors at high Reynolds numbers, highlighting the limitations of empirical approaches. Research results provide an important reference for calculating specific parameters in the implementation of coal spontaneous combustion prevention and control technologies.

Hybrid explosions involving multicomponent gases (CH4, CO) and coal dust, characteristic of coal spontaneous combustion, represent a critical mine safety hazard. To elucidate their dynamic mechanism, this study systematically characterized explosion behaviors under various gas and dust concentrations using a custom apparatus equipped with synchronous temperature/pressure sensors and high-speed photography. Experimental results demonstrate a "duality" in the function of coal dust and CO; they exhibit synergistic promotion in fuel-lean mixtures, whereas in stoichiometric or fuel-rich environments, they transition to a role of competitive inhibition. Post-explosion FTIR analysis of solid residues identified a microscopic reaction pathway comprising aromatic ring destruction, a dynamic equilibrium of intermediates, and final oxidation. Furthermore, the analysis of the dimensionless Biot number (Bi) and Thiele number (Th) confirmed that particle activation is governed by external heat transfer (Bi << 1) and that Th is positively correlated with explosion intensity, thereby kinetically validating the "competition and synergy" mechanism.Informed by these multi-dimensional analyses, a "competition and synergy" dynamic model is proposed. The model posits that the initial gas-phase equivalence ratio (Phi) acts as the critical switch dictating the explosion's evolutionary path, thereby bridging macroscopic phenomena with microscopic reaction pathways and physical control stages. This research establishes a novel, systematic theoretical framework for understanding, predicting, and mitigating such complex disasters.

Domino effects in chemical industrial parks (CIPs) may lead to severe accidents and substantial economic losses. Regarding safety investments to prevent domino effects in CIPs, traditional methods exhibit deficiencies in quantitative analysis, dynamic control, and predictive capability. Based on Monte Carlo simulation, the G1-improved entropy weight method, and the system dynamics (SD) theory, this study proposed an optimized decision-making method in safety investments for mitigating domino risks in CIPs. Besides, the potential economic losses arising from a domino accident in the CIP were calculated, which, together with safety investment and reduced domino risk, provide guidance for decision-makers. The results indicate that safety assessment investment is the most important factor in reducing domino risks, followed by emergency management, protective equipment and safety training investments in turn. Raising safety investments according to the optimal proportions obtained from SD simulations considerably lowers domino risks in CIPs. Furthermore, the feasibility of the model was validated using data from a CIP in Hunan Province, China. The proposed optimized decision-making model can dynamically predict the outcomes under various investment strategies, which enables managers to precisely allocate resources and effectively prevent or mitigate domino risks.

Traditional chemical inhibitors can easily lose moisture rapidly in the high-temperature environment of deep mining areas, and the effect is reduced. In order to alleviate the increasing risk of spontaneous combustion of coal in deep mining areas and solve the limitations of existing materials, a new type of deep eutectic inhibitor with high-temperature resistance has been developed. The inhibitor was synthesized by adding citric acid and proline as precursors, and adding VC and propyl gallate (PG). Through program heating oxidation, scanning electron microscope (SEM) and rheology tests, the inhibition characteristics and rheological mechanisms of four coal samples with different degrees of deterioration were systematically evaluated. The results show that the inhibitor significantly inhibits the oxidation process, delaying the critical temperature of CO acceleration by 20 degrees;C. The inhibition efficiency is particularly significant in the high-temperature stage. The CO inhibition rate of lignite (DHLC), gas coal (LZGC), coking coal (WJLCC), and anthracite (DLAC) reaches 62.54%, 60.96%, 58.00%, and 53.76%, respectively. The difference in the physical inhibition effect of coal samples with different degrees of deterioration at low temperatures is fundamentally due to different characteristics of their micropore structure. This study investigated the rheological behavior and established a nonlinear rheology model containing thermal effects, and its deterministic coefficient R2 reached 0.998. Using this model, the diffusion characteristics of inhibitors under different temperature gradients are clarified. In addition, sensitivity analysis shows that temperature has a significant impact on diffusion behavior, with a sensitivity index of 0.758.

To address the issue that traditional aqueous inhibitors are prone to dehydration and deactivation caused by high geothermal temperatures and strong air leakage in deep coal mine goafs,which makes it difficult to persistently inhibit coal spontaneous combustion(CSC),a deep eutectic inhibitor(DEI)based on a deep eutectic solvent as the liquid carrier and compounded with vitamin C(VC)and propyl gallate(PG)was proposed.The isothermal drying method combined with the Fick diffusion model was used to define a relative water retention index to evaluate the liquid domain stability of DEI at high temperatures.Low-field nuclear magnetic resonance(NMR)technology and a C600 microcalorimeter were utilized to investigate the infiltration and sealing laws at the pore interfaces and the oxidation exothermic characteristics of DEI on coals with different metamorphic degrees.Furthermore,density functional theory was applied to reveal the syner-gistic scavenging mechanism of VC and PG on typical active free radicals in coal.The results show that DEI effectively binds water molecules and delays water evaporation through its hydrogen bond network.The moderate evaporation of wa-ter at a high temperature of 80-100 ℃ induces the reconstruction of the hydrogen bond network to form a high-strength three-dimensional network structure.This enables its relative water retention index to reach a peak value of 0.78,demon-strating excellent high-temperature liquid domain stability.NMR results indicate that DEI can penetrate and reconstruct the pore network of coal,transforming the fluid in coal from a free state to a strongly bound state that is difficult to detach.The proportion of the bound water area increases to 70％-80％,and the bound porosity area of the first peak of micro-pores is enlarged,realizing the persistent sealing of primary micropores.Thermodynamic analysis demonstrates that after the DEI treatment,the endothermic termination temperatures of coal samples with varying metamorphic degrees are delayed to 174.5-183.6 ℃,and the corresponding phase-transition heat absorption is substantially increased by 161.39％-421.89％.Furthermore,the heat release during the low-temperature oxidation stage is reduced by 12.62％-34.84％,and the apparent activation energy in the temperature range of 200-300 ℃ is enhanced by 40.52％-100.67％.Quantum chemical calculations reveal that VC and PG can effectively scavenge the active free radicals during coal oxidation.Additionally,VC enhances the free-radical scavenging activity and persistence of PG through electron induction and intermolecular charge transfer,exhibiting a synergistic antioxidant effect.The research results provide theoretical and technical support for the persistent inhibition of CSC in deep coal mine goafs.

Coal spontaneous combustion (CSC) poses persistent safety and environmental challenges in underground mining. In this study, a novel in-situ sealing and water-retention double-network gel (S/C/P/T) was developed. The gel forms through ionic crosslinking between controlled release of Ca2 + from calcium L-lactate (CL) and sodium alginate (SA), combined with dynamic borate ester bonds between hydrolyzed sodium tetraborate (ST) and polyvinyl alcohol (PVA). Orthogonal experiments determined the optimal formulation: 2.0 wt% SA, 3.2 wt% PVA, 2.3 wt% CL, and 1.4 wt% ST, based on gelation time and water retention. FTIR and SEM investigated the formation of ionic and dynamic borate ester crosslinking, confirming a compact, continuous three-dimensional interpenetrating network. The gel evidenced the significant shear-thinning behavior and structural stability, with a maximum compressive strength of 38.92 kPa. Under varying pressures and flow rates, it achieved an average sealing efficiency exceeding 77.5%. Compared with the single-network gel, the S/C/P/T gel significantly reduced CO generation and increased the activation energy of the coal-oxygen reaction. Additionally, it exhibited higher characteristic temperatures, raising the maximum mass loss temperature of the coal sample by 7.70 degrees C. Molecular dynamics simulations yielded that the gel can overcome hydrophobic repulsion on the coal, facilitating the wetting and penetration of water molecules into the coal. Macroscopically, the gel isolated oxygen by wetting and encapsulating the coal, thereby suppressing exothermic oxidation reactions. Consequently, CSC is inhibited, and greenhouse gas emissions are reduced. These findings provide theoretical and engineering support for the prevention and control of CSC, as well as for environmental protection.

To address the challenges of rapid water loss and insufficient long-term inhibition efficiency of conventional inhibitors in the high-temperature environments of deep goafs, a novel, environmentally friendly Deep Eutectic Inhibitor (DEI) was synthesized. This DEI utilizes citric acid (Ca) and proline (Pr) as the hydrogen bond donor and acceptor, respectively, with ascorbic acid (VC) and propyl gallate (PG) serving as antioxidants. A moisture retention evaluation model based on Fick’s law of diffusion was established to systematically investigate the liquid-domain stability of the DEI across a temperature range of 30 °C to 120 °C. The results demonstrate that the DEI exhibits superior moisture retention capabilities under high-temperature conditions, with the relative moisture retention peaking in the 80–110 °C range. Mechanistically, the formation of a robust hydrogen bond network effectively counteracts moisture evaporation driven by thermal kinetic energy. Furthermore, the DEI demonstrated significant inhibition effects on four coal samples with varying degrees of metamorphism. Tests on oxidative heat release characteristics revealed that DEI treatment delayed the initial oxidation temperature of the coal. Kinetic analysis further indicated that during the critical oxidation stage (200–300 °C), the apparent activation energy of the treated coal samples increased by 10.28–18.9 kJ/mol, effectively suppressing the spontaneous combustion process. This study contributes to the development of high-efficiency and eco-friendly fire prevention materials for coal mines.

Abstract Gas drainage is essential for ensuring safe, efficient, and high-quality coal mine production. To address the common limitations of conventional borehole sealing materials, such as proneness to cracking, inadequate strength, and subsequent sealing failure,this study systematically investigates acomposite cement-based sealing material. The material was formulated using ordinary Portland cement as the base, supplemented with a composite concrete expansive agent (UEA), a polycarboxylate superplasticizer (PCE), 6 mm polyvinyl alcohol (PVA) fibers, and graphene oxide (GO). Macroscopic tests and microscopic characterization were combined to evaluate their properties and hydration mechanisms. The results demonstrate that the composite sealing material achieved a 60 d expansion rate of 1.521%, effectively counteractingthe shrinkage observed in ordinary cement, which exhibited a −0.53% shrinkage rate over the same period. This expansion is attributed to the reaction of UEA with cement hydration products, leading to the formation of ettringite (AFt) crystals. Microscopic analysis revealed that the oxygen-containing functional groups on GO surfaces are believed to provide heterogeneous nucleation sites in the developed multi-component system. This, combined with the crack-bridging effect of PVA fibers and the expansive action of UEA, synergistically accelerates the hydration of calcium silicates, leading to the formation of a denser microstructure. XRD analysis confirmed that the composite system did not alter the fundamental hydration products of cement but markedly acceleratedthe formation of AFt and the hydration reactions of C 3 S and C 2 S. At later stages, the reaction between calcium aluminate hydrate (C–A–H) and calcium hydroxide (CH) generated tetracalcium aluminate tridecahydrate (C 4 AH 13 ),further refiningthe microstructure. TG-DTG/DSC analysis verified the presence and thermal stability of key hydration products, including C–S–H, AFt, CH, and calcium carbonate. In summary, the composite material formulated in this study offers a promising material strategy for concurrently mitigating shrinkage and improving mechanical integrity. By providing insights into the synergistic hydration mechanisms across multiple length scales, this work contributes to the knowledge base for designing high-performance sealing materials for gas drainage applications.

In this paper, an environmentally friendly, efficiently adiabatic, and dynamically responsive siloxane composite hydrogel is constructed. It utilises a chemically simple, stable, and biocompatible trisiloxane wetting agent as its core, with a natural cellulose derivative, methylcellulose (MC), serving as the hydrogel matrix. Additionally, it incorporates highly efficient fire-resistant and flame-retardant additives. The composite hydrogel exhibits shearthinning behaviour (0 < n < 1), allowing for a reduction in viscosity during pipeline transport while retaining its adhesive properties upon application. Temperature-responsive phase transitions, regulated by MC and trisiloxane concentration gradients, balance flowability, high-temperature adhesion, and rapid thermal adaptation. Enhanced thermal stability is achieved through DMMP-induced char formation, which elevates the residual yield from 6.51 % to 13.91 % and forms an insulating barrier against heat and oxygen. Standard 1A wood crib fire tests demonstrate superior performance: the optimized hydrogel extinguishes flames within 126 s, achieves an average cooling rate of 6.13 degrees C/s, and prevents re-ignition (compared to 150 s for water and 147 s for Class A foam). Key mechanisms include oxygen-blocking phase-change layers, deep fuel penetration via high wettability, persistent insulation from carbonized gel networks, and dynamic flame inhibition. This study provides theoretical and technical support for the development of siloxane hydrogel forest fire suppression technology, demonstrating significant academic value and potential for engineering applications.

Matrix acidification, a key stimulation technique for permeability enhancement in unconventional reservoirs, induces complex molecular-scale alterations in coal's methane adsorption and diffusion behavior. This study employs molecular simulations to systematically probe pore structure evolution and methane dynamics post-acid treatment. Spatial mapping of preferential CH4 adsorption sites resolves density distributions near functional groups within the coal matrix. Results demonstrate that acidification increases porosity by 6.96 % and pore volume by 30.50 %, while reducing specific surface area by 3.56 %. Radial distribution function (RDF) analysis confirms methyl/hydroxyl group depletion critically diminishes methane adsorption capacity, with pyridinic/ thiophenic sulfur groups exhibiting minimal affinity. Acidification reduces the excess methane adsorption capacity by 26.86 % at 353.15 K and 9 MPa, yet elevates the surface diffusion coefficient (Ds) by 4.88 % and transport diffusion coefficient (Dt) by 4.74 % through enhanced pore connectivity. These molecular insights elucidate fundamental mechanisms governing methane sorption-diffusion trade-offs, providing a theoretical foundation for optimizing coalbed methane extraction.

Coal gas and coal spontaneous combustion compound disasters severely restrict the safe production of coal mines. Residual coal in goafs generally undergoes dynamic gas adsorption and desorption, and is continuously subjected to overburden stress. Its spontaneous combustion behavior is jointly dominated by the coupling effect of stress and coal gas. Existing studies on coal spontaneous combustion mostly focus on single influencing factors, lacking systematic investigations into the synergistic effect of stress and adsorbed gas, which fails to reveal the compound disaster mechanism and results in insufficient theoretical support for the collaborative prevention and control of gas and spontaneous combustion in goafs. Therefore, this paper presents a literature review on the spontaneous combustion characteristics and internal influence mechanisms of fractured coal bearing gas under stress. The influences of stress, temperature and other factors on the macroscopic characteristics of coal spontaneous combustion are summarized, and the staged evolution characteristics are illustrated based on oxidation kinetics. From the microscopic perspectives of functional groups, free radicals and pore structures, the internal correlation between coal structural evolution and spontaneous combustion during heating is revealed. The synergistic evolution laws of gas desorption-seepage and coal spontaneous combustion are summarized by combining macroscopic and microscopic results. This study clarifies the intrinsic mechanism whereby stress and adsorbed gas jointly control coal spontaneous combustion and remedies the deficiencies of single-factor research. It can provide a theoretical basis for the early warning, collaborative prevention and control of compound disasters as well as the safe and efficient mining of deep coal mines.

Excavation faces exhibit elevated fire risks owing to the accumulation of combustible materials, especially for high-geothermal tunnels. In this study, small-scale tunnel fire experiments were performed to investigate the smoke movement and temperature distribution under geothermal conditions. The results revealed that the geothermal activity induces a distinct asymmetrical temperature field, characterized by thermal stratification with heated airflow beneath the tunnel ceiling and cold external airflow at the bottom. In the event of a construction tunnel fire, the geothermal-induced thermal stratification confined the extent of the high-temperature smoke layer beneath the tunnel ceiling, while promoting the smoke diffusion across the cross section near the excavation face. Furthermore, the effects of geothermal temperature and pool fire size on longitudinal temperature distribution and vertical smoke stratification were revealed. The excess ceiling temperature decayed non-monotonically in high-geothermal tunnels, with a secondary peak at 4.1 m from the excavation face. The predictions of the excess ceiling temperature were provided for high-geothermal tunnel fires. The results revealed that geothermal conditions enhanced the intensity of vertical smoke stratification by acting as sustained external heat sources. By contrast, the positive effect of pool fire size on vertical smoke stratification was attenuated within the geothermal-affected zone.

To elucidate the pore-fracture structure evolution of low-, medium-, and high-rank coals under supercritical CO2 (SC-CO2) treatment, samples of varying coal ranks were subjected to SC-CO2 soaking at 10 MPa and 40 °C for 1–3 d. Multi-scale pore and fracture properties were characterized via low-temperature nitrogen adsorption, nuclear magnetic resonance, scanning electron microscopy, with Pearson correlation analysis employed to quantify relationship between parameters. The study found that SC-CO2 modifies the pore structure by promoting the transformation of micropores into mesopores, optimizing connectivity, and increasing surface roughness, with coal rank playing a decisive regulatory role. Due to their loose structure and high content of soluble components, low- and medium-rank coals exhibit significant parameter fluctuations and morphological reshaping under the synergistic effects of “dissolution-extraction-expansion.” In contrast, high-rank coals, due to their high aromatic content and dense structure, exhibit limited modification. Correlation analysis confirms that the response of low-, medium-, and high-rank coals to treatment duration follows a sequence of strong correlation, fluctuating behavior, and weak correlation, respectively. This study not only reveals the patterns of pore evolution but also provides a critical theoretical basis for optimizing injection parameters in CO2-enhanced coalbed methane extraction and geological sequestration.

During the process of lower layer mining, the overlying goaf is easily connected to the tunneling roadway, causing a symbiotic disaster of gas and coal spontaneous combustion. In order to prevent and control the symbiotic disaster, a kind of micro-particle foam slurry (MPFS) with good stability, homogeneity and strong fluidity was prepared by using cement, foaming agent and so on. The seepage-diffusion equation and the "stress-seepage field" fluid-solid coupling model were built. The distribution of plastic zone and seepage-diffusion in track trough and overlying goaf of 2311 working face were studied. The treatment key point of symbiotic disaster was delineated and the grouting prevention and control technology was proposed. The results showed that homogeneity of aqueous foam was expressed by first derivative of Sauter mean radius and the stability of aqueous foam were expressed by first derivative and second derivative of bubble count per mm2. When 2.5 wt% of surfactant was added, aqueous foam had the best performance characteristics. The reciprocal of fitting coefficient product of the viscosity-time fitting function was the key factor affecting the seepage distance of MPFS. When mixing composite slurry and aqueous foam with volume ratio of 1:5, the overlying goaf and the tunnel through area can be effectively blocked and covered. Field experiments further demonstrated that by grouting MPFS the gas accumulation was prevented, the oxidation and heating process of coal in goaf was interrupted. Grouting MPFS can control the symbiotic disaster caused by connection of overlying goaf.

Spontaneous combustion of coal is a major safety hazard currently facing coal mining operations. However, the existing fire prevention and extinguishing technology faces limitations including limited coverage and environmental hazards. In this paper, a new slurry foam gel material (SFGM) is proposed and developed for the technical bottleneck of coal spontaneous combustion prevention and control. The response surface method was used to optimize the material ratio. The foaming ratio of the new SFGM reached 5 times, and the stability coefficient reached 85.44. In simulated coal seam sealing tests, the sealing pressure stabilized at approximately -77.6 kPa, demonstrating a 45.3 % improvement in sealing capacity compared to conventional slurries. In the TG-DSC-GC coupled experiment, the mass loss of the coal sample decreased by 0.397 mg, representing a reduction of approximately 59.5 %. The carbon monoxide concentration decreased from 0.73 %o to 0.41 %o. The DTA data at 250 degrees C decreased from 0.76 degrees C/mg to -1.1 degrees C/mg, with the peak exhibiting a delayed trend. The SFGM overcomes the disadvantages of traditional inhibition techniques, including the inability to cover highposition cracks and the weak ability to interrupt chain reactions. SFGM plays a crucial role in ensuring safety in coal mine production. Furthermore, it provides a scientific basis for selecting and applying effective prevention and control technologies against spontaneous combustion of coal seams in deep mining operations under complex environmental conditions.

Aiming at quantifying the risk of coal mine gas explosions and addressing the deficiency in handling uncertainty in risk assessments, a gas explosion risk assessment method based on the Bayesian network and the cloud model was proposed in this study. Firstly, the main risk factors affecting gas explosions were determined, and the topology model of gas explosion risk was constructed. Meanwhile, the distribution ranges of prior and conditional probabilities of risk factors affecting gas explosions, as well as the probability values of basic events were determined in light of the cloud model theory. Furthermore, the probability of gas explosions was calculated by Bayesian forward causal reasoning, while the causation and mechanism of gas explosions was analyzed by Bayesian backward diagnostic reasoning. These reasoning technologies enabled the swift identification of the most probable risk factors. Finally, key risk factors affecting gas explosions were identified by means of Bayesian sensitivity analysis. The case study reveals that the risk probability of gas explosions in a coal mine in Anhui Province is 5.9%. However, the risk level of gas explosions rises substantially when the underground production conditions change, especially when multiple risk factors occur simultaneously.

To better evaluate the risk of coal spontaneous combustion in mines and effectively prevent coal spontaneous combustion accidents, this paper analyzes the influencing factors inducing coal spontaneous combustion, constructs 4 first-level indicators and 22 second-level indicators. The Analytic Hierarchy Process (AHP) and Entropy Weight Method (EWM) are then applied to calculate the weight coefficients of coal spontaneous combustion risk indicators. Finally, the Fuzzy Comprehensive Evaluation (FCE) method is utilized to determine the risk of coal spontaneous combustion in mines, so as to judge the danger of coal spontaneous combustion accidents and carry out practical applications. The results show that the AHP-EWM-FCE method can overcome the influences from subjective and objective factors in the evaluation process, while better handling fuzzy and uncertain problems. This enables a more scientific and accurate evaluation of the risk of coal spontaneous combustion in mines, identifies the factors most likely to cause accidents, and implements preventive controls in advance to ensure the safety of mine production processes.