Dust emissions from truck haul roads are the primary source of particulate pollution in open-pit mines. Current dust suppression methods mainly rely on water spraying and chemical suppressants, which generally suffer from high water consumption, high operating costs, and poor environmental adaptability. To address this issue, this study analyzed the airflow field characteristics around trucks on haul roads and their relationship with dust concentration distribution using numerical simulation. The results reveal that the wake vortex airflow and local negative pressure behind the truck are key factors driving the generation and dispersion of road dust. Based on this finding, a dust control method using airflow regulation was proposed, and its mechanism and effectiveness were systematically analyzed. The results show that the airflow regulation method effectively reorganizes the turbulent airflow behind the truck, creating an ordered flow pattern that tends to align with the ambient wind direction. This significantly reduces both the intensity and size of the wake vortex, and decreases the maximum extent of the recirculation zone from 14 m (without regulation) to 4 m behind the truck, thereby effectively mitigating the unfavorable flow conditions that promote dust generation and dispersion. Consequently, the airflow regulation method significantly reduces the dispersion of high-concentration dust during truck operation. It confines over 90% of dust particles below the pedestrian breathing zone height and reduces the peak dust concentrations in the driver's and pedestrian's breathing zones from 12.60 mg/m3 and 11.02 mg/m3 to 0.18 mg/m3 and 3.74 mg/m3, respectively, achieving effective control of road dust from truck haulage in open-pit mines. The proposed airflow-regulated dust control method offers a new technical approach for efficiently controlling dust emissions from truck haul roads in open-pit mines.

To characterize the thermal and mass transfer behaviors throughout the entire coal spontaneous combustion-extinguishing-reignition (CER) process, a comprehensive investigation was carried out using FTIR and STA-DSC tests. The findings revealed that, in comparison with raw coal, the characteristic temperatures corresponding to the pyrolysis and combustion stages of coal samples cooled under inert gases of varying concentrations were generally shifted to lower values. During the cooling phase, when pure N₂ was employed as the carrier gas, the mass of both SX and XJ coal samples exhibited a continuous downward trend as the temperature decreased. Conversely, under atmospheres containing 3%, 5%, 10%, and 21% O₂, the mass of the coal samples first showed a slight increase followed by a rapid decrease with falling temperature. Furthermore, the mass gain of the coal samples became more distinct as the oxygen concentration decreased. After being cooled under different atmospheres, the thermal and mass change behaviors of the coal samples differed markedly from those observed during the initial heating process. The most significant alterations were found in samples cooled with pure N₂, followed by those cooled with 10% O₂ and 21% O₂, and the least notable changes were in samples cooled with 3% O₂ and 5% O₂. During the first heating process, the Eₐ of the coal samples was highest in the first stage, followed by the third stage, with the lowest value in the second stage. In the cooling process, when the carrier gas was 3%, 5%, 10%, and 21% O₂, the Eₐ in the first stage was lower than that in the second stage. For coal samples subjected to inert gas cooling at different concentrations, the variation pattern of Eₐ in each stage was consistent with that of raw coal during the first heating process. However, the Eₐ values of the cooled samples were all lower than those of raw coal in the first heating process. Moreover, the order of the overall Eₐ of the coal samples after inert gas cooling was: pure N₂ < 10%, 21% O₂ < 3%, 5% O₂ < Raw coal.

Targeting the concealed thermal ignition hazards induced by long-term bottom heating in industrial hoppers, a multi-physics observation platform integrating bottom heating, internal temperature measurement, and infrared-visible imaging was developed. The 3D spatiotemporal evolution and ignition mechanisms of deposited AlMg alloy dust (20 and 60 μm) were systematically investigated. Results indicate that ignition transitions through four stages: preheating conduction, slow self-heating, local thermal runaway with a hypoxic plateau, and surface breakthrough with global combustion. Constrained by lower porosity and restricted oxygen diffusion, the 20 μm dust exhibits a prolonged smoldering induction period of 136.04 min (2.3 times that of the 60 μm dust). However, upon breaching the surface hypoxia limitation, its maximum heating rate precipitously surges to 1044.53 °C/min, reaching a 1019 °C peak. Analysis of the spatial temperature gradient (▽T) reveals that rapid mid-to-late surface combustion triggers a spatial gradient reversal, inducing an intense downward thermal reflux. Furthermore, surface cracks effectively facilitate inward oxygen transport, driving the flame to propagate outward in an “onion-like” concentric pattern. This lateral thermal coupling creates a unique intermediate enhanced reaction zone 1.5 cm from the center. Ultimately, this study clarifies the multi-stage ignition mechanism of “thermal accumulation-structural failure-combustion,” providing a vital thermodynamic basis for preventing concealed industrial fires.

Oil spills in inland rivers pose serious ecological and socio-economic risks, particularly under seasonally variable hydrological conditions. This study applied a sensitivity assessment framework to evaluate the effectiveness of conventional Oil Containment Booms (OCBs) under varying flow velocities and draft depths, comparing single and cascade deployment strategies. Results show that flow velocity is the primary determinant of containment efficiency. Below the initial failure velocity, all tested OCBs achieve near-complete containment, making deployment decisions primarily dependent on ecological and operational considerations. Once the flow velocity exceeds this threshold, containment efficiency decreases significantly, and draft depth becomes decisive: OCBs with at least 0.8 m draft consistently outperform shallow-draft booms. Cascade deployment further improves performance under medium- and high-flow conditions, with five-boom cascades identified as a practical and cost-effective choice. These findings support a flow-velocity-based deployment strategy, highlighting draft depth, cascade configuration, and cascade size as critical parameters for effective emergency response planning in inland river systems.

Sealed fire zones in coal mines present severe reignition risks during unsealing. This issue stems primarily from the overlapping and coupling of multiple parameters during the coal spontaneous combustion-extinction-reignition process (CERP), making it difficult to distinguish key characteristic information and accurately guide on-site disposal. Spontaneous combustion tendency theoretical calculations and a self-developed similarity simulation test system were used to systematically investigate the gas-thermal characteristics and spatiotemporal evolution laws throughout the CERP. The results show that the heat propagation rate in the vertical direction is higher than that in the horizontal direction. High-temperature zones (>30 degrees C) are distributed approximately in a "flat elliptical" shape centered on heating rods D2 and D3, while the high-temperature zone centered on heating rod D1 presents an "inverted conical" distribution. The area of the high-temperature zone gradually expands from bottom to top, with the top layer having the largest area. Convective heat transfer of high-temperature flue gas dominates the heating/cooling process of loose coal. When reheated after cooling under a pure N-2 atmosphere, the coal reaches a higher maximum temperature than that of the first heating process, corresponding to the shortest heating time. This is followed by cooling under 10% O-2 and 21% O-2 atmospheres and finally under 3% O-2 and 5% O-2 atmospheres. Coal samples cooled under different atmospheres show higher concentrations of CO, CO2, CH4, and C2H4 compared to raw coal. Meanwhile, when the coal samples cooled under different atmospheres are reheated for reignition, each gas concentration at the same stage is generated earlier than raw coal, and the order of gas concentrations (from highest to lowest) is pure N-2 > 10% O-2, 21% O-2 > 3% O-2, 5% O-2 > raw coal. The findings provide technical support for "medium-large" scale tests of sealed fire zones as well as a theoretical basis for guiding the on-site management of fire zones.

Tunnel blasting generates substantial quantities of dust and toxic gases, particularly in high-altitude tunnels, posing severe occupational hazards to construction personnel. Comparing the generation and migration characteristics of these pollutants is crucial for identifying the difficult-to-remove components and applying target control measures, thereby enhancing the overall removal efficiency of blasting fumes under press-in ventilation. Therefore, in this study, the production and diffusion characteristics of blasting fumes in a high-altitude tunnel are analysed based on field measurements and numerical simulations. Results show that blasting fumes in highaltitude tunnels contain dust, CO, CO2, SO2, H2S, NO, and NO2. Among them, dust and CO are the key components with the peak concentrations of 977.8 mg/m3 and 1607.5 mg/m3, respectively. Under press-in ventilation, the diffusion velocities of dust and CO are 0.094 m/s and 0.068 m/s, respectively; after 600 s of ventilation, the residual CO mass fraction within 60 m from the blasting face is 1.5 times that of dust. The results indicate that CO is more difficult to remove than dust. Moreover, as the initial concentrations of blasting fumes decrease and airflow velocity at the air-duct outlet increases, the pollution duration shortens linearly and exponentially, respectively. The study demonstrates implementing CO-targeted purification and source control technologies could effectively shorten the pollution duration of blasting fumes.

Many mining areas are confronted with problems such as reignition during the unsealing of fire zones. To obtain the evolution characteristics of pore-fracture structures and free radicals after cooling and extinguishing under different atmospheres, tests were conducted using EPR and BET methods. The research results show the following: After SX and XJ coal samples were cooled under a pure N-2 atmosphere, the pore volume of micro-pores and meso-pores decreased to the greatest extent, while the pore volume of macro-pores increased to the greatest extent. This was followed by the cooling effects under 10 % O-2 and 21 % O-2, and finally by those under 3 % O-2 and 5 % O-2. Both the fractal dimension of pore surface (D-L) and the fractal dimension of pore space (D-H) of the coal samples were smaller than those of the raw coal. For the coal samples cooled under the pure N-2 atmosphere, the D-L was the largest, indicating the highest pore surface roughness; this was followed by the samples treated under 10 % O-2 and 5 % O-2, and finally by those treated under 3 % O-2 and 21 % O-2. In terms of D-H, the coal samples cooled under the pure N-2 atmosphere had the largest D-H value, corresponding to the highest complexity of pore space; this was followed by the samples treated under 10 % O-2 and 21 % O-2, and finally by those treated under 3 % O-2 and 5 % O-2. Cooling under different atmospheres exerts two effects on free radicals: promoting their generation and accelerating their consumption. At oxygen concentrations of 3 % O-2 and 5 % O-2, the consumption effect of free radicals was stronger than the generation effect. When cooling was performed with 10 % O-2 and 21 % O-2, the generation effect of free radicals was slightly stronger than the consumption effect. The type and quantity of free radicals determine the initial reaction activity. After cooling under different atmospheres, the storage content of free radicals before potential reignition was inconsistent among the coal samples, but all were higher than that of the raw coal. The order of free radical storage content was as follows: pure N-2 > 10 % O-2, 21 % O-2 > 3 % O-2, 5 % O-2 > Raw coal.

Many mining areas are facing problems such as reignition during the process of unsealing fire areas. The generation laws of gases and the transformation process of coal surface functional groups during the coal spontaneous combustion-extinction-reignition (CER) were studied by using programmed temperature rise for coal spontaneous combustion(CSC) and in-situ infrared spectroscopy experiments. Results show that: during the first heating, the concentrations of various gases and oxygen consumption increased slowly first and then exponentially with rising temperature. When cooled with pure N2, they dropped rapidly; however, in atmospheres of 3% O2, 5% O2, 10% O2, and 21% O2, there was a lag effect in the early stage of extinguishment, and the gas concentrations decreased as the temperature continued to drop. Compared with the first heating stage, oxygen consumption was higher when cooling; additionally, a lower oxygen concentration corresponded to a higher level of oxygen consumption. For coal samples cooled in various atmospheres, the gas concentrations during the second heating were all higher than those in the first heating. When cooled in 3% and 5% O2, the consumption of active functional groups exceeded their generation; in 10% and 21% O2, the generation was slightly stronger than consumption. After cooling in various atmospheres, the storage amounts of functional groups were all higher than those in raw coal, in the order: pure N2>10% O2, 21% O2>3% O2, 5%O2>Raw coal. The findings of this research offer a theoretical foundation for curbing the rapid spread and preventing the reignition of fires, and provide technical support for environmental protection in fire-affected areas.

Tunnel blasting produces substantial dispersed dust, where ventilation remains the primary pollution control method, its effectiveness diminishes over extended tunneling distances. To address this limitation, this study introduces an innovative discrete foam-air curtain synergy system for localized dust control in large cross-section tunnels, effectively mitigating turbulence-induced foam dispersion. An optimized composite formula of discrete foam comprising 5 % alpha-olefin sulfonate (AOS), 4 % sodium dodecyl sulfate (SDS), 1 % sodium tripolyphosphate (STPP), 2 % Cocamide DEA, and 0.6 % sodium lignosulfonate (SL) demonstrated superior foam performance: extended stability (lifetime > 28.8 s), enhanced air-corrosion resistance (dust loss rate = 0.37 %), and improved dust wettability (contact angle = 7.81 degrees). Force modeling of the foam monomer determined air curtain velocity as 3-17 m/s range, 0.46 m installation distance relative to foam generator. As for the foam jet characteristics, an operating voltage of 3.5 V combined with a nozzle spacing of 20 cm achieved a coverage distance of 4.6 m, with a distribution uniformity coefficient exceeding 0.99. The vertical downward foam nozzle configuration achieved reduced dispersion coefficients as 0.19-0.46 compared to 30 degrees directional arrays. Full-scale experimental validation revealed that the synergic system achieved 73.38 % dust suppression efficiency, outperforming standalone foam system by 22.69 %. The dust suppression rate ranged from 0.45 to 0.90 mgm(-3)s(-1), corresponding to 1.11-2.10 times the performance of conventional ventilation methods. These results provide a practical strategy for dust control in tunneling construction.

To control tunnel blasting dust pollution and safeguard worker health, numerical simulations of dust migration in the tunnel were conducted, and the response surface method was employed to assess the key factors and their interactions. Firstly, a full-scale tunnel model was validated with on-site testing. Subsequently, single-factor experiments identified air velocity in the duct, altitude, and particle diameter as the three most influential factors. Finally, a response surface test was designed based on the Box-Behnken principle. According to the response surface results, the significant order of factors affecting the dust level at the height of the breathing zone and in the working area is as follows: air velocity in the duct > particle diameter > altitude. Additionally, the interaction between air velocity in the duct and particle diameter is significant. In contrast, the interactions between air velocity in the duct and altitude, as well as between altitude and particle diameter, are negligible.

Carbon monoxide (CO) generation during roadway blasting in underground mines poses a serious threat to the health and safety of workers. The generation and diffusion characteristics of CO during and after blasting must be better understood for its prevention and control. Herein, this study investigated the generation and diffusion characteristics of CO during blasting in underground upward-inclined roadways. The influence of several key parameters, including the wind velocity at the air duct outlet, the initial CO concentration, and the roadway inclination angle (0°, 30°, 45°, 60°, and 90°), on the diffusion of CO after blasting was analyzed. The results showed that the CO concentration after blasting exhibited double-peak characteristics corresponding to the blasting shock wave and press-in ventilation. After blasting, the moving velocity of the CO concentration peak exhibited a linear increase with the wind velocity at the air duct outlet. Meanwhile, both the peak CO concentration and the polluted length in the roadway increased linearly with higher initial CO concentration. Following these simulation results, the computational models for the concentration peak value and location, polluted length in roadway of CO were established. Furthermore, the area of the vortex zones formed at the roadway corners expanded as the inclination angle of the roadway increased. This enhancement in vortex size promoted the accumulation of CO within the roadway and prolonged the CO discharge time. This study provides practical reference for the efficient prevention and control of CO produced by roadway blasting in underground mines.

Dust generation from wet-mix shotcrete (WMS) is a major source of aerosol pollutants in underground construction. However, research on aerosol pollutant control equipment during the WMS process is still scarce. To achieve effective control of aerosol pollution during WMS production, this study introduced and applied air curtain dust suppression technology. A multi-dimensional jet test platform was used to investigate the dust suppression effects of a direct air curtain, an inner ring wall-attached air curtain, and an outer ring wall-attached air curtain during WMS production. By analyzing the variation characteristics of the dust concentration curve, key characteristic points were determined, and the diffusion phase and sedimentation phase were demarcated. With the incorporation of a K-C air curtain, the range reduction rates for the diffusion and sedimentation phases reached 51.92% and 80.85%, respectively, with an aerosol control efficiency of 57.10%. Additionally, numerical simulation was conducted to investigate the flow field characteristics during WMS production. It was found that the radial velocity gradient of the entire flow field in the spatial coordinate system was reduced, with a maximum reduction rate of 57% at (Y-axis = 560 mm). Furthermore, the affected area of the vorticity in the main jet shear layer was significantly reduced.

Wet shotcreting operations in tunnels produce large amounts of dust that threaten workers' health. In this study, a coupled airflow - dust model was developed based on gas - solid two-phase flow theory to simulate dust migration under different ventilation airflow and shotcreting positions. Using CFD simulations in ANSYS FLUENT and field data validation, the spatiotemporal evolution of dust concentration was analyzed. The results indicate that dust diffusion can be divided into three zones - jet - recirculation, transition, and stable - and that the average dust concentration decreases along the airflow direction, following the order: working face region > shotcreting operation region > transition region > stable region. Increasing ventilation speed effectively reduces peak dust levels and shortens the time to reach permissible concentration. An air duct outlet velocity of 12 m/s (corresponding to a ventilation volume of 1374.1 m3/min and an average tunnel cross-sectional wind speed of approximately 0.64 m/s) is identified as the optimal velocity. Different spraying positions significantly alter dust distribution characteristics, with crown spraying showing the widest and most uneven diffusion. The findings provide a quantitative reference for ventilation optimization and occupational dust control during tunnel shotcreting operations.

Wet-mix shotcrete (WMS), widely used in tunnel construction, is a major aerosol pollutant source. Aerosol pollutants pose health risks and negatively impact operations, increasing maintenance costs and construction delays. However, understanding aerosol generation and mechanisms during WMS remains inadequate. This study focuses on two key factors: concrete slump and air pressure, which directly influence the jet flow characteristics. Through detailed observation of jet formation, the breakup and atomization patterns of the jet, as well as the size and the mass concentration of the resulting aerosol pollutants, were analyzed. A lubricating layer was formed near the pipe wall during effective pulsating flow. This layer undergoes fragmentation during the primary breakup stage, followed by atomization under air shear force at the secondary breakup stage. As concrete slump and air pressure increase, the jet pattern transitions from a non-effective slug flow to a primary breakup dominated flow, eventually to a secondary breakup dominated flow. The spread angle and fragment ratio of the jet exhibited a positive correlation with the concrete slump and air pressure. Notably, the main generation of aerosol pollutants occurred at the secondary breakup stage. The total and respiration concentration of aerosol pollutants in the secondary breakup dominated flow were 4.5 % and 4 % higher, respectively, than in the primary breakup dominated flow. This study provides valuable insights into the aerosol generation during WMS, shedding light on the underlying mechanisms and facilitating a better understanding and management of the associated risks.

Coal spontaneous combustion (CSC) in goafs is a serious hazard to underground mine safety. Traditional inhibitors usually have weak bonding strength and high fluidity. Therefore, they adhere poorly to coal surfaces in steeply inclined goafs and show limited suppression efficiency. To address this issue, this study developed a novel composite inhibitor with enhanced bonding strength and adhesion properties for CSC mitigation in steeply inclined goafs. The bonding, adhesion, antioxidant characteristics, and CSC suppression performances of molasses solution (MS) and its composites with CaCl2 and MgCl2 were systematically evaluated through laboratory and field tests. Results showed that 30 % MS exhibited strong coal adhesion, with a bonding strength of 132.21 N and an adhesion rate of 6.65 %, representing 140 and 41.5 times increases, respectively, compared to pure water. When combined with 15 % CaCl2 and 10 % MgCl2, the composite inhibitor significantly suppressed coal oxidation at low temperatures, reducing oxygen consumption rates by 72.9 % (90 degrees C), 84.3 % (170 degrees C), and 62.2 % (250 degrees C), with corresponding inhibition rates of 73.4 %, 87.1 %, and 77.9 %. Field tests in a steeply inclined goaf showed CO concentrations decreased by 47.5 % (intake side) and 35.2 % (return side), effectively controlling CSC. Furthermore, the inhibition mechanisms of the molasses-based composite were elucidated. This study demonstrates that molasses-based composite inhibitors provide an effective and practical approach for preventing CSC in steeply inclined goafs.

The drilling-blasting method is a widely used and efficient excavation technique in tunnel construction.However,it generates significant dust pollution,rendering comprehensively and rapidly assessing the distribution of dust concentration during tunnel construction crucial.Existing sensor-based dust-monitoring technologies provide only sparse dust data,while computational fluid dynamics(CFD)simulations are computationally intensive and time-consuming.This study introduces a data-driven approach that integrates principal component analysis(PCA)and Gaussian process regression(GPR)to decompose and reconstruct dust concentration fields,overcoming the limitations of conventional techniques.The approach reconstructs the global dust concentration field on a two-dimensional tunnel plane using sparse sensor measurements,eliminating the need for repeated,time-consuming numerical simulations.Key factors influencing reconstruction accuracy were investigated.The results demonstrate that appropriately increasing the number of PCA modes and sensors improves accuracy,while optimizing sensor placement significantly enhances performance.Specifically,a high-precision reconstruction of the dust concentration field was achieved with an optimized arrangement of five sensors.Additionally,a comparison of different stages in the dust migration process revealed that the method achieved the highest reconstruction accuracy during the steady diffusion stage,highlighting the significant influence of airflow on reconstruction accuracy.Finally,the method was applied to predict dust concentration in a tunnel under construction.The relative error was 19.79%,while the computation time was merely 0.28%of that required for CFD calculations,demonstrating its efficiency and reliability.

The physicochemical properties of coal dust significantly affect its toxicity and dust suppression efficiency. Currently, lab-crushed coal dust is commonly used for characterization instead of the original coal dust (OCD) sampled from underground mining sites. This practice leads to an inaccurate understanding of the underground coal dust properties. To address this issue, the study directly collected 18 OCD samples from various underground mining sites and characterized their physicochemical properties, and the variation of these physicochemical parameters of OCD with various coal rank were analyzed. The results show: OCD has a small particle size (average 26.49 μm), and around 21% of particles are under 10 μm. OCD has a well-developed pore structure, with an average total pore volume of 8.24 × 10-3 cm3/g and an average specific surface area of 8.24 m2/g. OCD samples have a high oxidation degree, and the average relative content of total oxygen-containing functional groups is 45.71%. Between the 32 measured physicochemical parameters of OCD, 10 moderately correlates with R 0 and 6 highly correlates with R 0. These parameters mainly involve wettability, pore structure, moisture content, and elemental composition. The findings present valuable insights into accurately assessing the toxicology and health risks of coal dust in underground mining sites and for selecting efficient dust control technologies in different coal mines.

ObjectiveBlasting operations in mines generate significant amounts of impact dust, which poses a significant risk of pneumoconiosis and threatens workers' health. This also results in substantial direct economic losses annually, severely impacting China's pursuit of high-quality economic development. Existing ventilation and dust removal technologies have proven inadequate. Among various developed dust reduction methods, wet dust suppression technology has improved continuously. A key advancement is the use of ultrasonic atomizing nozzles, known for their low water consumption, effective atomization, and superior dust capture efficiency. Consequently, a dry mist dust suppression technology has been proposed to efficiently manage dust from mining blasting operations, improve working conditions in return airways, and safeguard the physical and mental health of workers. This study investigates the application of dry mist dust suppression technology in roadway-type mining faces of metal mines to achieve these objectives.MethodsThis study focused on a roadway-type mining face in a certain iron ore mine. The initial investigation involved analyzing the physical and chemical characteristics of dust generated during blasting operations, particularly examining mechanisms that influence its wetting properties. Dust samples were classified through flotation into hydrophilic and hydrophobic types. Further analysis was conducted on their wetting properties, surface morphology, particle size distribution, and surface pore structure to explore the physicochemical characteristics affecting dust wetting. Three types of ultrasonic atomizing nozzles were selected for testing their atomization characteristics under different pressure parameters using an atomization test platform. This study analyzes the influence of different air-water parameters on atomization characteristics and identified the optimal nozzle for dust reduction applications. Furthermore, a dry mist dust suppression device was designed and developed for use in mining. Field experiments evaluated dust distribution in return airways before and after blasting operations, with and without the application of mist spraying for dust suppression.ResultsThis research indicated that the impact dust generated during blasting operations was predominantly hydrophilic. The dust wetting properties were primarily influenced by factors such as particle size and surface porosity. Critical to the efficiency of dry mist dust suppression were the droplet size and quantity. The median droplet size D50 showed an inverse relationship with the ratio of air pressure to water flow rate. Among the tested nozzles, SK-508, SV-980, and SV-882, the SK-508 ultrasonic atomizer exhibited the smallest average droplet size and consumed the least amount of water, thus conserving water resources effectively. Under conditions of 0.7 MPa air pressure and a water flow rate of 0.1 kg/s, the SK-508 demonstrated significant atomization effects, making it the optimal nozzle for dust suppression among those tested. Leveraging the advantages of dry mist dust suppression technology and the atomization characteristics of ultrasonic nozzles, a dry mist dust suppression device was developed. Field tests of the prototype demonstrated its notable effectiveness in reducing both total dust and respirable dust, achieving a high level of dust suppression efficiency.ConclusionsA dry mist dust suppression device was developed to address the issue of dust in return airways, effectively managing both total dust and respirable dust in mining tunnels. It achieves efficient control of impact dust generated during blasting operations. This innovation provides a solid theoretical foundation for advancing the national green mining initiative and contributes to establishing a comprehensive technical system for dust control in mines.

In this study, sodium dodecyl benzene sulfonate, triton, guar gum and sodium polyacrylate are selected as the composite raw materials of dust suppressants through the determination of physical and chemical properties of single components. Design expert software is used to carry out the mixture design, the determination of experimental parameters and the response surface analysis of the sedimentation rate, evaporation resistance property, surface tension, contact angle of coal dust with the reagent. According to the response surface analysis results, the optimal ratio of the reagent has been determined, which is 39.8% for sodium dodecyl benzene sulfonate, 53% for triton, 3.9% for guar gum, and 3.3% for sodium polyacrylate. The results of infrared spectrum show that the dust suppressant had a significant effect on the content change of hydroxyl of hydrophilic functional groups of coal dust. The results of scanning electron microscope experiments show that the dust suppressor has good wetting and binding effects on coal dust. The toxicity test shows that the coal sample did not have the acute inhalation toxicity characteristics of hazardous waste. The dust reduction experiment in similar space shows that the dust reduction efficiency of this new dust suppressants is 95.3%, which is 28.1% and 10.2% higher than that of natural dust fall and water spray dust fall. The conclusions of this study are of great significance for improving the dust reduction efficiency of mine dust suppressants, the dust prevention technologies, the working environment of underground workers, and reducing the incidence of pneumoconiosis.

During tunnel construction, the protracted mucking phase poses significant occupational health risks, particularly from dust exposure. This study delves into comprehensive numerical simulations to examine the spatiotemporal dynamics of dust particles during the mucking process. A distinct 'bimodal pattern' was characterized by higher concentrations in the mucking area (0-30 m) and the inverted arch area (60-110 m), where concentrations exceed 30 mg/m3 under all conditions. To address this issue, a novel dust removal system has been developed. Integrating six dust collectors and one air curtain device, a dust removal trolley is strategically positioned at z = 70 m to locally purify the air. The extracted wind speed of the dust collectors (Vinlet1) and the air curtain's wind speed (Vinlet2) are optimized based on ventilation conditions and dust dispersion characteristics. This system effectively reduces dust mass concentrations to below 4.8 mg/m3 at six worker locations.