Mining Height Research Articles

Ground Stress Analysis and Automation of Workface in Continuous Mining Continuous Backfill Operation

The cost, complexity, lack of filling space and time create challenges in the longwall backfill operation, resulting in poor subsidence control and reduced productivity. This paper proposes an automated continuous mining and continuous backfill (CMCB) method by examining its key requirements and investigates the optimum sequence of coal panel (such as drifts) excavation to ensure ground strata control at relatively high productivity. The automated CMCB adopts the highwall mining technique underground, which enables easier automation at the workface. A numerical simulation of the Changxing coal mine in China was undertaken, and five different sequences of coal excavation were investigated, using the automated CMCB excavation parameters (assuming a 4 m width cut, 5 m mining height for a 200 m long coal slice) to determine the optimum sequence of resource excavation. The plastic zones and vertical displacement across the five models were analyzed. Simulation results of the 5 m high coal seam excavation show that the odd-even slice (OES) mining sequence, which has a vertical ground displacement of 74 mm, is the most efficient excavation method, due to its effective stress redistribution and lower induced ground displacement.

Prediction of the Height of Water-Conductive Fractured Zone under Continuous Extraction and Partial Backfill Mining Method—A Case Study

Longwall backfill mining effectively mitigates the height of water-conductive fractured zone (HWCFZ), preventing it from reaching the overlying aquifer and thus preserving the groundwater. However, it has the disadvantages of insufficient filling time and space as well as the mutual constraints between filling and mining. A novel continuous extraction and partial backfill (CEPB) water-preserving mining method was therefore proposed. The analytic hierarchy process (AHP) method was employed to identify the factors affecting the HWCFZ of CEPB, and five main factors, namely, the hard-rock lithology ratio, mining height and depth, and the width of the Wongawilli and protective block, were determined based on the weight distribution. UDEC software was used to establish a numerical model to simulate the HWCFZ under five factors. By using a multiple linear regression analysis of the numerical simulation results, a model for predicting the HWCFZ was established. It was applied in a colliery of the Yu-Shen mining area, and the HWCFZ was 57.7 m, 9% higher than that of borehole television logging of 53.1 m from the field measurement, indicating its rationality. Subsequently, the model was generalized and applied to the whole mining area, and the thematic map of the HWCFZ and the protective zone thickness of CEPB and longwall caving mining were obtained. The criterion for water-preserving mining based on the equivalent permeability coefficient of the protective zone is then proposed, which can provide guidance for the mining parameters optimization of the CEPB.

Evolution Characteristics of Overlying Strata Fractures in Paste Composite Filling Stope

Paste composite filling mining (PCFM) is one of the effective ways to achieve water-preserved mining (preservation of the waterproof strata). To investigate the laws of fracture propagation of the overlying strata in the PCFM stope, a kinematic model of overlying strata in the PCFM was established, which identified the major determinants to the development of overlying strata fractures. Taking the 112,201 working face of the test mine as the research background, the physical similar simulation, numerical computation, and theoretical analysis were combined to analyze the development characteristics of overlying strata fractures in the PCFM under the reaction between many factors (mining height, filling ratio, burial depth). The results show that the larger the mining height of the working face, the larger the development degree of overlying strata fractures. When the mining height is smaller, fractures are mostly distributed on both sides of the coal wall; when the mining height is larger, overlying strata fractures are mostly distributed on both sides of the coal wall and the upper part of overlying strata. The larger the paste filling ratio of the working face, the smaller the development degree of overlying strata fractures. Overlying strata fractures are mostly distributed in overlying strata on both sides of the coal wall. When the filling ratio of the working face increases, it is possible to effectively control the development of overlying strata fractures. The shallower the burial depth of the working face is, the faster the fractures are developed. With the increase of the burial depth, the development of overlying strata fractures is reduced, and overlying strata fractures will finally tend to be a stable value. The research results provide an important theoretical foundation for the application of the localized paste filling mining technique in the water-preserved mining, and also complement the theories of filling mining.

The Principle and Practice of Strong Mine Pressure Control in the Initial Mining and Caving Stages under Multiple Key Strata

The mechanism of strong mine pressure control in the initial mining and caving stages under multiple key strata (MKS) was studied by theoretical analysis, numerical simulation and field measurement in order to avoid the dynamic pressure accidents caused by the MKS breaking in interactions in the initial mining and caving stage. Panel 13103 (P13103) in the Shan Xi Jinshen Shaping Coal Mine was used sas the study site. The overlying structure and the breaking characteristics of the key strata were analyzed and the overlying structure model of longwall top-coal caving (LTC) under MKS was established. Reasonable initial mining heights and initial caving positions were determined and the spatial and temporal characteristics of ground pressure and roof structure of the working face in the mining process were obtained. The results show that, in the scheme of starting top-coal caving after the working face advanced 20 m, the support damage ratios were all greater than 50% with roof weighting, which is prone to induce prop crash accidents. The dynamic load formed by the second weighting was greater than first weighting under the MKS. The duration of mine pressure tended to be stable with fully developed caving zone heights. With the designed mining scheme, the safe and efficient mining of P13103 is guaranteed.

Severe Damage Law on the Ground Surface Induced by High-Strength Mining: A Case Study From the Shendong Coal Field in China

High-strength mining has the characteristics of shallow buried depth, large mining height, and fast mining speed. Under the condition of high-strength mining, the overburden moves violently and the surface damage is serious. It has caused serious ecological security problems in the mining area. In order to solve this problem, it is necessary to adopt the technology of restoration while mining. The key to the effective implementation of this technology is to clarify the real-time distribution law and generation mechanism of surface damage. In this paper, field investigation and the theoretical analysis method are used for related research. The results show that the surface strenuous move duration is long, the strenuous move area is large, and the surface discontinuous deformation is fully developed. With the characteristics of stepped crack lags behind the location of the working face, the stepped crack spacing and periodic weighting interval are equivalent. Through discussion and analysis, it is found that the cause of serious damage is the strata movement mode of high-strength mining in “two zones” mode. Under the “two zones” mode, the roof has easy-to-slip instability, the bedrock is completely broken along the direction of the bedrock breaking angle, and the weak anti-disturbance ability of the loose layer leads to the surface becoming severely damaged. The research results can provide reference for the formulation of follow-up ecological real-time restoration measures in similar mines.

High Mining Face Flexible Reinforcement to Prevent Coal Wall Spalling by Cuttable Aluminum–Plastic Pipe Pre-Grouting

A larger mining height leads to easy caving of the coal wall in the working face. The flexible reinforcement method during the mining period of the working face affects the normal mining of the working face, and the high strength of the traditional bolt/cable material affects the operation of the shearer drum, so it is necessary to seek a reinforcement material which does not affect the production and the drum coal cutting. This paper proposed a technical scheme of coal wall reinforcement by pre-grouting with a cuttable aluminum–plastic composite pipe which is easy to cut during mining in the working face, tested the mechanical properties of the “grouting + flexible pipe” specimen, and obtained the optimal support spacing by numerical simulation and carrying out an industrial test. The results show that the tensile strength of aluminum–plastic composite pipe is much higher than that of coal spalling and the elongation is much higher than that of the anchor rod. When double-row composite grouting holes are arranged 1.5 and 3.0 m away from the roof, the supporting effect is better. Underground grouting shows that pre-grouting before mining according to the advancing speed of the working face 10–14 days in advance can effectively fill the coal cracks and significantly improve the integrity of the coal wall.

Research on Formation Mechanism and Evolution Pattern of Bed Separation Zone during Repeated Mining in Multiple Coal Seams

Mastering the formation mechanism and dynamic evolution pattern of bed separation zone during repeated mining is the key to the success or failure of separation grouting injection technology. Taking a mine in Ningdong as the engineering background, using the research methods of theoretical analysis, numerical simulated, and field measurement, four overburden structure models of single or multiple key strata with repeated mining and single or multiple key strata without repeated mining were constructed. The evolution pattern of bed separation zone was studied from four aspects: bed separation zone development mechanism, formation position, development form, and change of clearance. The results showed that when a single key stratum of repeated mining exists between coal seams, it is difficult to form a large separation area because there is no key stratum during the upper coal mining, and a separation area will be formed below the key stratum when mining the lower coal. When the key stratum exists above all coal seams, a large separation zone will be formed under the key stratum when the upper coal is mined. When mining the lower coal, when the coal seam spacing is less than 4 times of the mining height of the lower coal, the crack will penetrate the upper coal floor. If the key stratum is not completely broken, secondary separation may occur. When multiple key strata are all located above all coal seams, there will be bed separation zone under the high-level key stratum. When multiple key strata and coal seams are distributed at intervals, the separation below the high-level key stratum during upper coal mining and the separation below the low-level key stratum during lower coal mining are formed. Because the high-level key stratum bends and sinks after being affected by the mining of coal 1, the clearance of bed separation during mining coal 2 is slightly less than that during mining coal 1, which is contrary to the pattern that the greater the bed separation clearance increases with the increase of mining height.

Analysis of the Coal Fluidization Mining Process with the Continuous-Discontinuous Coupled Particle-Block Method

In situ fluidization mining is a promising method which shows considerable potential for reducing the ecological influence impacts of coal mining. During fluidization mining, coal gangue will be separated from the ores, filled back, and returned to the excavation region, which, depending on the filling rate, greatly reduces the stratum deformation of strata, depending on the filling rate. Numerical simulations can assist engineers in evaluating stratum deformation and optimizing affordable designs with affordable costs. Accordingly, in this work, a continuous–discontinuous element method is adopted, which is a coupled particle–block finite-discrete element method with an explicit integration formulation, which is adopted for simulating the coal in situ fluidization mining–filling processes. The theory concept of an “equivalent mining height” is utilized to define the backfill mining height. The results partly reveal the influences of the filling rate on the stratum deformation, surface subsidence, and rock burst phenomena, all of which further indicate the advantages of the fluidization mining method.

Study on the Migration Law of Overlying Strata on the Working Surface of Large Mining Height in Y.C.W Coal Mine

The migration law of overlying strata on working face is of great significance for safe mining of working face. In this paper, theoretical calculation, numerical simulation, and similar simulation are used to study the distribution characteristics, migration, and fracture law of key strata in the overlying strata of 130204 working face of Y.C.W coal mine and the relationship between the development height of water flowing fractured zone and the spatial position of weak aquifer. The theoretical calculation results show that there are “one main two sub” key strata in the overlying strata of 130204 working face, which play an important role in controlling rock movement. Numerical simulation and similar simulation results show that the first weighting step distance of the direct roof of 130204 working face is about 30-40 m. The initial weighting interval of the basic roof of the working face is about 70-80 m, and the periodic weighting interval is about 23.5-25 m. After the first weighting and multiple periodic weighting of the basic roof of the working face, the first subcritical layer is located in the caving zone, the second subcritical layer is located in the fracture zone, and the main key layer is finally located in the bending subsidence zone. The final height of the caving zone of the overlying strata is about 24 m, and the height of the water flowing fractured zone is about 130 m. Since the water-conducting fractured zone is connected and passes through the second subcritical layer with weak water-bearing property, it is possible for the water permeability accident of the working face. Therefore, in order to ensure the safety of the working face, the water should be detected and released in advance during the mining of the working face.

Floor Disturbance and Failure Characteristics of Super-Large Mining Height Working Face

The failure depth of the working face floor caused by mining is a key parameter to predict water inrush from the working face floor. Extensive research has been conducted on the floor failure zone of the working face. However, in recent years, there have been few studies on the floor failure law of the working face with a super-large mining height (over 20 m) in the western mining area of China. In this paper, the working face with a super-large mining height of 24 m in Longwanggou Coal Mine was studied. Electrical monitoring and numerical simulation of the working face floor were carried out. The measured floor failure depth of the working face is 15 m while the average numerical simulation result is 11 m. When compared with the calculation results of the statistical analysis formulas, the floor failure depth of the working face with a super large mining height obtained from field measurement and numerical simulation is smaller. The reason for the smaller failure zone of the floor of the super large mining height working face is that the falling roof inhibits the pressure relief of the floor, the large mining height reduces the advance pressure, and the shear stress of the floor decreases. The research methods and findings are of great significance to the prediction of floor failure and water inrush in working face with a super-large mining height, the prevention and control of water disasters in coal seam roof and the monitoring of mine pressure.

Study on Deformation and Fracture Evolution of Underground Reservoir Coal Pillar Dam under Different Mining Conditions

Coal mine underground reservoir water storage technology is an effective technical way to achieve high efficiency of coal mining and protection of water resources. The stability of coal pillar dam plays a decisive role in the safe and stable operation of underground reservoirs. Mining of adjacent working faces and long-term water erosion are the main influencing factors of stability of coal pillar dam. In this paper, a fluid-solid coupling calculation model for the deformation and evolution of coal pillar dam was established by FLAC3D numerical simulation software and the underground brine reservoir of Lingxin Coal Mine of Shenning group as an engineering background. The paper studied systematically the deformation, failure, and stress evolution of the dam with coal pillars soaked in water for a long time under different working face inclining length, coal pillar width, mining height, and water pressure. The simulation results showed that the degree of deformation and failure of the coal pillar dam continued to increase with the continuous advancement of the working face. The plastic zone of the coal pillar dam was increased by approximately 23.53%, the maximum vertical stress was increased by approximately 95.78%, and the maximum vertical deformation was increased by approximately 68.18%. The influence of each factor on the deformation and failure of overburden strata is quite different. The development range of plastic zone, the maximum vertical stress, and the maximum vertical deformation were increasing with the increased of working face inclined length and mining height. The increasing width of coal pillar would lead to the decrease of maximum vertical stress. The increase of water pressure would lead to the decrease of maximum vertical deformation. It can be seen that the inclined length of the working face is the main factor affecting the deformation and failure of the coal pillar dam. Coal pillar width and mining height are the main factors affecting the development of plastic zone. This study reveals the law of deformation and fracture evolution of coal pillar dam under different mining conditions, which can provide a reference for the design of coal pillar dam of coal mine underground reservoir.

Stability Analysis of “Support-Surrounding Rock” System for Fully Mechanized Longwall Mining in Steeply Dipping Coal Seams

The key to safe and efficient longwall mining of steeply dipping seams lies in the stability control of the “support-surrounding rock” system. This study analyzes the difficulties encountered when controlling the stability of the support during the longwall mining process of steeply dipping coal seams in terms of the characteristics of the nonuniform filled-in gob using a combination of physical tests, theoretical analyzes, and field measurements. Considering the floor as an elastic foundation, we built a “support-surrounding rock” mechanical model using data obtained on support-surrounding rock systems in different regions and the laws of support motion under different load conditions. Our findings are summarized as follows: first, depending on the angle of the coal seam, the caving gangue rolls (slide) downward along the inclined direction, resulting in the formation of a nonuniform filling zone in the deep gob where the lower, middle, and upper sections are filled, half-filled, and empty, respectively. In addition, an inverted triangular hollow surface is formed on the floor of the gob in the middle and upper sections behind the support. Furthermore, as the angle of the coal seam, length of the working face, and mining height increase, the characteristics of the nonuniform filled-in gob are enhanced. Second, we found that because of the gangue support, the “support-surrounding rock” system is relatively stable in the lower part of the working face; however, in the middle and upper sections of the working face, the contact method and loading characteristics of the support are more complicated, making stability control difficult. Third, the magnitude and direction of the load, action point, and mining height affect the stability of the support to varying degrees, with the tangential load and action position of the roof load having the most significant impacts on the stability of the support. Under loading by the roof, rotation and subsidence of the support inevitably occur, with gradually increasing amplitudes and effects on the intersupport and sliding forces. Finally, we found that overall stability can be achieved by adopting measures involving “sliding advancement of supports” and applying a “down-up” removal order. These research results serve as a significant reference and guidance for longwall mining applications.

Research on Roof Structure and Determination of Working Resistance of Shallow Buried Single Key Stratum Based on Grid Drillhole Field Method

Abstract The roof structure of the stope is the core of revealing the weighting mechanism and determining the working resistance of support. The Shenfu Dongsheng coal field of China has abundant reserves of shallow coal seam. The phenomena of strong ground pressure and step subsidence caused by the mining of shallow buried single key stratum (SBSKS) poses a serious threat to the fragile environment. Revealing the shape and movement process of roof structure of SBSKS is the primary prerequisite for ensuring safe mining of working face. Firstly, the field measurement technology of the space grid-like drill field was developed to construct vertical holes and incline holes in the auxiliary headgate gateway and tailgate airway ahead of the working face and to obtain the measured data of the broken position and vertical displacement of the roof by the drilling peep and multipoint displacement. Secondly, the key parameters of the stope roof were analyzed by the grid drillhole filed method, for example, the inclined roof break angle, the rotation angle, the thickness of equivalent immediate roof (EIR), and the roof structure-articulated level and shape. Then, we combined with the mining face comparison of compression laws revealing the time and space relationship between the movement of the roof structure and the roof weighting, and three more dangerous states of the roof were determined. Finally, the roof structure of SBSKS is moved upward through the field research on the 22201 working face, the “high step rock beam” structure and the advanced breaking position of the roof are obtained, and the calculation equation of the support resistance in large mining height face is given. The research results provide scientific guidance for the safety of SBSKS coal seam and provide technical support for green mining in ecologically fragile mining areas.

A deep‐hole microblasting technique for controlling coal wall spalling during mining of a vertically jointed seam

AbstractThe vertically‐jointed coal seam, especially after water drainage, is easy to lead to large‐area coal wall spalling (CWS). To alleviate the problem, a strut subjected to equivalent central‐concentrated force was proposed for elaborating critical conditions for coal instability based on CWS characteristics, determining the main control factors. The sensitivity analysis of factors driving CWS revealed that the coal between 3.3 and 4.56 m was the most vulnerable. A microblasting technique was proposed for controlling CWS by increasing the friction coefficient at the weakened‐primary coal interface, improving the coal stress, and reducing the equivalent mining height. The paper presented the application of universal distinct element code models to simulate the CWS mechanism with different joint mechanical parameters and microblasting heights. The reduction of spalling intensity indicates that the microblasting weakening of the upper part coal could improve the overall stability of the coal. LS‐DYNA is employed for simulating the fractures development between blasting holes, and the rationality of optimized blasting parameters is revealed. The fracture characteristics of the observation hole in field demonstrated that the hole was effectively fractured by microblasting. The spalling parameters including depth, width and frequency were obviously reduced, which showed the rationality in microexplosion controlling spalling.

Research on the Movement Law of Roof Structure in Large-Inclined Coal Seam Working Face: A Case Study in Liu.Pan.Shui. Mining Area

In the Liu.Pan.Shui. coal field, Guizhou Province, China, 35°∼60° steeply inclined coal seams are widely distributed, and the coal resources present are of high quality and are mostly coking coal. However, because the roof overlying rock structure is affected by the geological conditions at a large dip angle, the combined cantilever beam structure of the overlying rock near the working face and the overlying rock masonry beam structure in front of the working face have different migration laws from when the condition of the near-level coal seam is generated. The pressure has emerged with new characteristics, posing a threat to coal mine production safety. Therefore, by establishing a mechanical model of roof overlying rock structure in accordance with the characteristics of coal seam inclination, mining height, and goaf overlap in the Liu.Pan.Shui mining area and using the analytical formula of material mechanics to calculate the behavior of rock pressure, guide the roof weakening means, construction technology, and parameters. It is used to quantitatively control the transportation load of the overlying rock on the roof of the large inclination coal seam and realize the safe and efficient mining of the precious coal resources of the Liu.Pan.Shui coal field.

Study on the Law of Subsidence of Overburden Strata above the Longwall Gob

In recent years, with the increase of depth and intensity of coal mining, geological disasters in deep engineering occur frequently. It is essential to study the law of subsidence of overburden after mining for analyzing the mechanism and control of geological disasters in deep engineering. However, the value of the subsurface subsidence factor and other overburden subsidence parameters could not be obtained easily. In this paper, the strata bulking of the caving zone, the bed separation of the fractured zone, and the dilatation of bending zone were considered a kind of expansion in the vertical direction uniformly. An assumption on vertical expansion value distribution of overburden strata above the longwall gob was proposed. Based on the assumption, a formula of the subsurface subsidence factor was deduced according to such parameters as the bulking factor, mining depth, mining height, and surface subsidence factor. Moreover, many field data were used to verify the correctness of the assumption by the data fitting method. The results show that the exponential function could well describe the expansion distribution characteristic of overburden strata and subsurface subsidence in the vertical direction. The parameter a in the deduced formula influences the shape of the subsurface subsidence curve; it is called the subsurface subsidence influence factor (SSIF). The SSIF, maximal vertical expansion value, and the mining depth-to-mining height ( MD / MH ) ratio influence the subsurface subsidence factor. The expansion distribution (E-D) factor is defined to describe the subsidence characteristic of overburden strata above the longwall gob by the surface subsidence factor and bulking factor of the caving zone. The E-D factor presents the logarithm relation with the MD / MH ratio, and the range of its maximum is 2.84~3.40. The case study demonstrates that the subsurface subsidence factor calculated by the proposed method has higher precision, and the mean errors between the calculated value and the measured value are less than 2%.

Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face with Large Cutting Height

When gob-side entry retaining is adopted in the mining face with large cutting height, due to large stope space, strong dynamic pressure, and other reasons, the filling body is usually broken and unstable due to improper width of filling body, and the stability of surrounding rock of a roadway is poor. Taking the actual project of Shaqu mine as the background, we analyze the stability factors of gob-side entry retaining with large mining height, and considering the lateral pressure and overlying load on the filling body, the mechanical model of a gob-side retaining roadway is established, the calculation method of the reserved width of the filling body is simplified, and the reasonable width of the filling body is obtained quantitatively. Through the monitoring results of numerical simulation and field test, the rationality of the calculation results of the reserved width of filling body is verified. The results show that if the width of the filling body is too small, it will not be able to bear the load of the overlying strata, resulting in the fragmentation of the filling body. The larger the width of the filling body, the greater the cutting resistance provided, which can reduce timely the stress on the roadway and above the filling body, and the more stable the retaining roadway is, but when the width increases to a certain value, the displacement of the surrounding rock of the roadway has changed little. When the width of the filling body is 4 m, the stability of gob-side entry retaining can be guaranteed.

Dynamic dispersion and high-rise release of coal dust in the working surface of a large-scale mine and application of a new wet dust reduction technology

To determine the dynamic dispersion process of coal dust in a working surface characterized by a large mining height, as well as the formation time and the dispersion range of a heavy pollution area of coal dust in the same working surface, we restored the field production conditions and performed a simulation analysis by using the FLUENT software. The results of our analyses showed that: within 30–120 m from the lower wind side of the hydraulic support's advancing point, the minimum airflow speeds along the machine passage and the sidewalk were 0.41 m/s and 0.24 m/s, respectively. At T = 60 s, coal dust initially formed at ⁓ 40 m from the downwind side of the front drum and the average mass concentration in the high-concentration coal dust contaminated area was 1840 mg/m3. At T = 600 s, coal dust diffusion achieved a dynamic balance, at 60 m from the downwind side of the front drum; in this case, the average coal dust mass concentration in the high-concentration coal dust dispersion area reached 1470 mg/m3. A new wet dust reduction technology was installed at the starting location of a highly polluted area: the average coal dust reduction rates were 73% and 82%. These results confirm the efficiency of the proposed technology in reducing the spread of coal dust pollution and in avoiding the problem of high coal dust concentration in large mining environments.

Model of Overlying Strata Structure in Large Mining Height Excavating Condition and Calculation of Support Working Resistance

Aiming at the wide range of rock strata movement and collapse, poor stability and high damage rate of the working face support and being prone to crushing of the support in large mining height face, analog simulation, theoretical analysis, and field measurements have been carried out to analyze roof breaking structure form and calculation method of support reasonable support resistance of large mining height face. The researches show that, affected by the space of the mined-out area, the roof of the large mining height working face will take on the structural form of “combined suspended beam-nonhinged roof-hinged roof”; the interaction system between the support and the surrounding rock consists of “hinged roof structure,” “nonhingeable roof structure,” “combined suspension beam structure,” and the support. The support resistance should adapt to the change of the overlying rock structure’s instability movement, bearing the weight of the structure itself and the additional load generated by the movement. Combining with the mining conditions of Jinhuagong Coal Mine’s large mining height face in Datong mining area, the reasonable support resistance of the working face support is analyzed. The mine pressure monitoring shows that the ZZ13000/28/60 type support and shield hydraulic support can meet the requirements of roof control; the research results ensure the safe mining of the large mining height face.

Study on the coupling migration law of airflow-respiratory dust of an 8-m high fully-mechanized mining face

8-m super-high fully mechanized mining face has been successfully applied in China, which has brought many difficulties to dust control. The main reason is that the mining height increases and the dust distribution and evolution law are quite different. Targeting the 12,513 fully-mechanized mining face in Bulianta Coal Mine of China in this paper. The spatial evolution of airflow-respiratory dust of an 8-m high fully-mechanized mining face is analyzed using numerical simulation and underground measurement methods. The results reveal that the numerical and measured results are consistent. At the working range from 15 m in front of the shearer to 30 m behind it, the wind speed increases with an average rise of 70% on the coal cutting side. The airflow diffusion at the working face is primarily longitudinal and partly transverse. Along the airflow direction, the respiratory dust concentration in the pedestrian space first increases and decreases, followed by a marginal increase and gradual decrease，and the dust concentration increased with the increase of height, the migration distance of dust particles was directly proportional to time, and the smaller dust particles were prone to transverse diffusion. In the range of 20–30 m from the downwind side of the shearer, the transverse diffusion of coal cutting dust and the dust produced by support coal falling show conversion, leading to the increase of dust concentration. Under the same dust production intensity, compared with ordinary mining height, with the increase of mining height, the influence range of dust diffusion is wider, the floating duration is longer, and the space dust concentration will be reduced, and the support coal falling dust is the main dust pollution source in pedestrian space. The results reveal that the numerical and measured results are consistent, and obtained the relationship of spatial evolutions of respiratory dust