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The problem of dust pollution in the open-pit coal mine significantly impacts the health of staff, the regular operation of mining work, and the surrounding environment. At the same time, the open-pit road is the largest dust source. Therefore, it analyzes the influencing factors of road dust concentration in the open-pit coal mine. It is of practical significance to establish a prediction model for scientific and effective prediction of road dust concentration in the open pit coal mine. The prediction model helps reduce dust hazards. This paper uses the hourly air quality and meteorological data of an open-pit coal mine in Tongliao City, Inner Mongolia Autonomous Region, from January 1, 2020, to December 31, 2021. Create a CNN-BiLSTM-Attention multivariate hybrid model consisting of a Convolutional Neural Network (CNN), a bidirectional long short-term memory neural network (BiLSTM), and an attention mechanism, Prediction of PM2.5 concentration in the next 24h. Establish prediction models of parallel and serial structures, and carry out many experiments according to the change period of the data to determine the optimal configuration and the input and output size. Then, a comparison of the proposed model and Lasso regression, SVR, XGBoost, LSTM, BiLSTM, CNN-LSTM, and CNN-BiLSTM models for short-term prediction (24h) and long-term prediction (48h, 72h, 96h, and 120h). The results show that the CNN-BiLSTM-Attention multivariate mixed model proposed in this paper has the best prediction performance. The mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2) of the short-term forecast (24h) are 6.957, 8.985, and 0.914, respectively. Evaluation indicators of long-term forecasts (48h, 72h, 96h, and 120h) are also superior to contrast models. Finally, we used field-measured data to verify, and the obtained evaluation indexes MAE, RMSE, and R2 are 3.127, 3.989, and 0.951, respectively. The model-fitting effect was good. [ABSTRACT FROM AUTHOR]

Based on the greening and low interference disposal requirements of coal gangue in high-yield and high-efficiency mines in Inner Mongolia and Shaanxi, and by integrating the existing theories and technologies such as underground filling technology of coal gangue, mine yellow mud grouting technology, and the evolution law of mining overburden fractures, a technology of filling goaf with coal gangue slurry for green disposal of coal gangue is proposed. The principle and technical framework of the technology of filling goaf with coal gangue slurry are clarified. This paper expounds on the technological process of technology of filling goaf with coal gangue slurry, establishes three types of slurry filling systems, such as centralized ground layout, ground and underground coordinated layout, and centralized underground layout, and constructs three slurry filling methods, including low-level grouting, adjacent level grouting, and high-level grouting, forming seven kinds of technology models of filling goaf with coal gangue slurry, including ground centralized pulping + high-level grouting, ground centralized pulping + adjacent grouting, ground centralized pulping + low level grouting, ground and underground coordinated pulping + adjacent grouting, ground and underground coordinated pulping + low level grouting, underground centralized pulping + adjacent grouting, and underground centralized pulping + low level grouting, and gives the selection process of technology models of filling goaf with coal gangue slurry. Based on the different conditions and requirements of Haidaze Coal Mine and Huangling No. 2 Coal Mine, engineering tests were carried out on two different technology modes, namely, ground and underground coordinated pulping + low level grouting and ground and underground coordinated pulping + adjacent grouting, based on simulation tests of low level grouting and adjacent grouting. The tests prove the feasibility of filling goaf with coal gangue slurry and explore the way for the theoretical research of the technology of filling goaf with coal gangue slurry and greening and low interference disposal of coal gangue. [ABSTRACT FROM AUTHOR]

Highwall mining is a method that involves using a continuous highwall miner system (CHM) to extract coal from the remaining coal seams, which has proven to be an effective and safe method for extracting coal after open-pit mining. However, application cases globally have shown that the feasibility of highwall mining in open-pit coal mines is subject to geological conditions, mining techniques, and other factors. If application conditions are not suitable, equipment may be trapped under collapsed coal–rock masses and unable to be retrieved, resulting in severe safety issues for slope stability. To meet the real-world demand for extracting the remaining coal in open-pit coal mines in China, it is urgent to conduct a feasibility evaluation of highwall mining in these areas. This paper establishes a mathematical evaluation framework for assessing the feasibility of highwall mining by summarizing a large number of engineering application cases globally and analyzing various technical characteristics such as geological deposit conditions, mining techniques, and technical equipment. The analytic hierarchy process (AHP), fuzzy comprehensive evaluation (FCE) and variable weight theory (VWT) are utilized in conjunction to form this framework, which includes four secondary indicators: geological deposit factors, mining technique factors, safety impact factors, and economic evaluation factors, and 20 tertiary sub-indicators, along with their corresponding characteristic values. The feasibility sub-set is divided into four categories: infeasible, basically feasible, relatively feasible, and highly feasible, and the values of the sub-indicators strictly follow and represent these four levels of feasibility. Weight vectors for the sub-indicators are obtained through a judgment matrix established within the mathematical evaluation framework. The fuzzy relationship matrix of the sub-indicators is constructed using fuzzy mathematical membership functions, and the final feasibility evaluation is determined through two-level comprehensive evaluation. The accuracy of the model is verified using the characteristic parameters of open-pit coal mines under two different conditions (JZT coal mine in Inner Mongolia, China, and GC coal mine in Australia). The results demonstrate that the maximum evaluation membership degree for the JZT mine is 0.7113, belonging to the "highly feasible" level, while the GC mine is 0.3304, belonging to the "basically feasible" level, which aligns well with real-world usage, proving that the evaluation model can effectively reveal the performance and membership degree of each indicator in different application cases. By quantitatively characterizing the feasibility level of highwall mining technology under different application conditions, this evaluation model can provide scientific guidance for coal mining enterprises to introduce CHM for highwall mining operation in open-pit coal mines. [ABSTRACT FROM AUTHOR]

Roadway mine pressure monitoring is one of the important means to ensure the safe and efficient mining of coal mines. However, the traditional monitoring methods have the disadvantages including lack of systematim, low accuracy, poor reliability, and difficulty in networking. In this paper, by using the grating sensor as a monitoring method, a roadway mine pressure grating monitoring system including roof separation, bolt stress, surrounding rock stress and bolt load monitoring was systematically designed and develop, to solve the shortcomings of current monitoring methods. Firstly, taking the 81303 return airway of a coal mine in Inner Mongolia as the research object, the stress distribution law of the two coal pillars was clarified by numerical simulation, and the optimal measuring point layout scheme of the roadway was determined. Secondly, the overall framwork of the roadway mine pressure grating monitoring system was built, and the design and research of the system hardware configuration and monitoring software were carried out to realize the real-time online monitoring and data processing of the roadway mine pressure. In addition, the industrial application test shows that the mine pressure law obtained by the system is generally consistent with those from the traditional method, and the relative error of the monitoring parameters is up to 1.16%, which verifies the effectiveness and adaptability of the mine pressure grating monitoring system. [ABSTRACT FROM AUTHOR]

Filling mining is the main mining method in coal mine, and its safety is the pillar of the overall safety of the mine. Filling mining can effectively protect the surface environment, better solve the problem of ground pressure, and maximize the recovery of underground resources. Therefore, this method has an irreplaceable role in deep mining of coal mines and is highly valued by the mining industry all around the world. In order to evaluate the implementation effect of filling mining, a comprehensive weighting-set pair analysis safety evaluation model is established. This model optimizes the subjectivity of analytic hierarchy process (AHP) and the objectivity of Entropy Weight Method (EWM) in traditional methods. Besides, we add experts' weight to Entropy Weight Method. The combination of the two methods makes the index weight more reasonable and effective, and can more fully reflect the difference and correlation of index. Firstly, the accident causation analysis and taxonomy (ACAT) is used to find out the accident causation factors of filling mining, and then, the AHP and EWM are used to determine the weight of each evaluation index from different perspectives. Then, the evaluation group is established to score the importance of each expert, so as to reduce the subjectivity of expert scoring. Finally, according to the principle of set pair analysis, the safety evaluation model of filling mining is applied to Yuxing Coal Mine in Inner Mongolia. The evaluation result shows that the safety grade of this mine is grade 1 "safety." This paper provides a new way and direction for the comprehensive evaluation of similar mining methods, the establishment of index system, the acquisition of index weights, and the evaluation of safety level, which has promotion and application value. [ABSTRACT FROM AUTHOR]

Groundwater is a primary freshwater resource for human consumption and an essential source for industry and agriculture. Therefore, understanding its spatial and temporal trends and drivers is crucial for governments to take appropriate measures to manage water resources. This paper uses Gravity Recovery and Climate Experiment (GRACE) satellite data and the Global Land Data Assimilation System (GLDAS) to derive groundwater storage anomalies (GWSAs) and to analyze the spatial and temporal trends of GWSA in different regions of China (Xinjiang, Tibet, Inner Mongolia, North China Plain, South China, and Northeast China). It used groundwater-level observation data to verify the accuracy of GWSA estimates and analyzed the drivers of regional GWSA changes. The results showed that: (1) GWSA in South China increased at a rate of 4.79 mm/a from 2003 to 2016, and GWSA in other regions in China showed a decreasing trend. Among them, the decline rates of GWSA in Xinjiang, Tibet, Inner Mongolia, North China Plain, and Northeast China were −6.24 mm/a, −3.33 mm/a, −3.17 mm/a, −7.35 mm/a, and −0.75 mm/a, respectively. (2) The accuracy of the annual-scale GWSA estimates was improved after deducting gravity losses due to raw coal quality, and the correlation coefficient between GWSA and groundwater levels monitored by observation wells increased. (3) In Xinjiang, the annual water consumed by raw coal mining, industrial, and agricultural activities had a greater impact on GWSA than rainfall and temperature, so these human activities might be the main drivers of the continued GWSA decline in Xinjiang. Water consumption by raw coal mining and industry might be the main drivers of the continued decline in GWSA in Inner Mongolia and the North China Plain. The increase in groundwater storage in South China was mainly due to the recharge of rainfall. [ABSTRACT FROM AUTHOR]

Effective high slope risk assessment plays an important role in the safety management and control of the open-pit coal mining process. Traditional slope stability risk assessment methods rarely consider the time factor or evaluate the dynamic change of high slope in an open-pit mine at a certain time in a sensitivity assessment. This paper develops an interval trapezoidal fuzzy soft set method to achieve the high slope dynamic risk evaluation. The proposed dynamic interval trapezoidal fuzzy soft set method for risk assessment of high slope in an open-pit coal mine is developed by integrating the time points and weights of slope risk factors. The extended interval trapezoidal fuzzy soft set was used to calculate the weights of risk factors at different times, and the Fuzzy Analytical Hierarchy Process (FAHP) method was applied to determine the weights of risk factors. The weight change of different risk factors with time can be easily achieved with the proposed method. As a case study, this approach is implemented into a risk assessment model for the north high slope in Shengli #1 open-pit mine located in Xilinhot, Inner Mongolia. The model complies with three time points and contains 4 primary risk factors (S) and 17 secondary risk factors. The results indicated that the hydrological climate conditions and slope geometry conditions were the high risk factors affecting this open-pit coal mine slope. The reasonability and effectiveness of the evaluation results were verified with in-situ observations and measurements. This dynamic risk assessment method is helpful for improving safety management and control for the high slopes of open-pit mines in the coal mining process. [ABSTRACT FROM AUTHOR]

Coal is one of the fundamental fossil energy supporting the world's economy. The synergistic development between efficient coal mining and ecological environment protection is the inevitable requirement for the preservation of global harmony. As the world's largest coal producer, China has conducted a strategic shift from east to west in terms of the exploitation of its energy resources, posing a serious threat to the fragile ecological environment of the western region. In particular, the surface subsidence caused by coal mining is the root of the ecological deteriotation and the destruction of ground structures. However, it is difficult to reveal the law of large-scale surface subsidence in western mining areas merely by conventional measurement methods such as leveling, on account of the high intensity of coal seam mining, the weakness of the lithology of overlying rock and the large thickness of wind-blown sand strata. In view of this, small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) technology was used in this study to obtain the time series of surface vertical displacement during the whole mining process of the 2401 working face in the Yingpanhao coal mine, Inner Mongolia. Based on the deformation data, the dynamic evolution characteristics of surface subsidence under high intensity mining in the western mining area were analyzed exhaustively. It was found that the surface subsidence is characterized by an extensive coverage range (48.52 km2) with minimal ground settlement (250 mm) in the study area. Meanwhile, the boundary shape of the subsidence basin followed a "circular-parallelogram-trapezoid" changeable process and the coverage area of the basin experienced three stages: a linear increasing period, a temporary stagnation period, and a re-expansion period. Furthermore, there existed an abnormal uplift phenomenon on the east side of the open-off cut in the 2401 working face. Combined with the structure of overlying strata, this paper carried out a preliminary analysis on the reasons of the abovementioned phenomenon. The research results are of vital realistic significance for ground buildings and ecological environmental protection in the aeolian sand mining area in Western China. [ABSTRACT FROM AUTHOR]

This paper concerns the comparison of two sample non parametric regression. An asymptotically correct simultaneous confidence band (SCB) is proposed for the difference of two-sample non parametric regression functions to achieve the goal of comparison. Simulation experiments provide strong evidence that corroborates the asymptotic theory. The proposed SCB is used to analyze different samples of strata pressure data from the Bullianta Coal Mine in Erdos City, Inner Mongolia, China. [ABSTRACT FROM AUTHOR]

High-yield coal mining and ecological environment protection are the main aspects of the sustainable development of ecologically fragile mining areas in Western China. This paper briefly describes the development and current situation of solid filling coal mining in China, puts forward a green and sustainable filling coal mining method providing a maximum annual treatment capacity of waste gangue of 2 4 million tons, and analyzes the mechanical compaction properties of solid waste gangue, eolian sand, and loess in these areas. Taking a Coal Mine in Inner Mongolia, China, as an example, the effects of three key indices, namely mining height, face width, and backfill materials' compaction ratio (BMCR) on the subsidence, horizontal deformation, horizontal movement, inclined deformation, and curvature of Quaternary aquiclude are studied. At a mining height of 3 m and BMCR = 80%, the maximum aquifer subsidence is below 168 mm. Based on the surface vegetation growth capacity analysis, the design principle of controlling the SBM key parameters by the ecological water level threshold is substantiated. The results show that the mining height and the BCMR of goaf are the key control indices affecting the stability of Quaternary aquifers, the evolution of ecological water level, and the production of surface vegetation. Combining the underground intelligent dry coal preparation and in-situ filling coal mining technology with a reasonable adjustment of the above parameters, the ecological environment protection can be realized for the whole life cycle of local coal seam mining in the areas under study. [ABSTRACT FROM AUTHOR]

High-intensity coal mining in grasslands has negative impact on the surface ecology of the mining area and its surroundings. This impact shows spatio-temporal heterogeneity due to differences in mining intensity at various life stages. Based on remote sensing images and experimental test data, this paper took the Baorixile Surface Coal Mine (BSCM), which as the largest open-pit mine in eastern Inner Mongolia, as an example to analyze surface ecological quality and risk at the whole life cycle. In total, 13 indices from three aspects of site structure, spatial pattern, and ecological function were selected to assess surface ecological quality. The geoaccumulation index and potential ecological risk index were used to analyze the ecological risk of surface soil. Identification of impact range of mining activities and pollution sources of soil heavy metal was obtained by correlation analysis. At present, the BSCM is at a stable stage. Ecological quality showed a deteriorating trend during the reaching and stable stages. The soil organic matter content at the BSCM was lower than the Second National Soil Survey and exhibited a decreasing tendency. A low ecological risk was found in soil, and Cd was the main potential ecological risk element. The surface ecology of the boundary and its 2 km buffer zone was affected by mining activities in the BSCM. Mining activities may have an impact on the surface ecology of the 5 km buffer zone. This study provides a reference method for ecological quality assessment and impact scope determination of similar mining areas. [ABSTRACT FROM AUTHOR]

Underground mining in coal mining areas will induce large-scale, large-gradient surface deformation, threatening the safety of people's lives and property in nearby areas. Due to mining-related subsidence is characterized by fast displacement and high nonlinearity, monitoring this process by using traditional and single interferometric synthetic aperture radar (InSAR) technology is very challenging, and it cannot accurately and quantitatively calculate the deformation of the mining area. In this paper, we proposed a new method that combines both multitemporal consecutive D-InSAR and offset tracking technology to construct a complete deformation field of the coal mining area. Taking into account the accuracy of multitemporal consecutive D-InSAR in calculating small deformation areas and the ability of offset tracking to measure large deformation areas, we utilized their respective advantages to extract the surface influence range and applied an adaptive spatial filtering method to integrate their respective results for inversion of the deformation field. 12 ascending high-resolution TerraSAR-X images (2 m) from September 3, 2018, to October 26, 2019, and 39 descending Sentinel-1 TOPS SAR images from August 5, 2018, to November 4, 2019, in the Ordos Coalfield located at Inner Mongolia, China, were utilized to obtain the whole subsidence field of the working faces F6211 and F6207 during the 454-day mining period. The GPS monitoring station located in the direction of the mining surface is used to verify the accuracy of the above method; at the same time, to a certain extent, the difference between the unmanned aerial vehicle's DSM data acquired after coal mining and the Shuttle Radar Topography Mission (STRM) DEM can qualitatively verify the accuracy of the results. Our results show that the results of TerraSAR are basically consistent with the deformation trend of GPS data, and that of Sentinel-1 have large errors compared with GPS. The maximum central subsidence reaches ~12 m in the working face F6211 and ~4 m in the working face F6207. In the working face F6207, the good agreement between GPS and TerraSAR results indicated that the method above using high-resolution SAR data could be reliable for monitoring the large deformation area in the mining field. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a comprehensive analysis of roof strata conditions, shield pressure, and ground surface subsidence above Panel 42105 of the Buertai Coal Mine in Inner Mongolia, China. A 3D geological model and a 2D numerical simulation model are established to examine the roof strata structures with varying strata conditions. Numerical simulation results demonstrate that the hard rock 1 and 2 roof layers are, on average, likely to break 20 m and 57 m behind the coal face, respectively. It is concluded that when the immediate roof is relatively thin, a cantilever beam is formed, whereas a Voussoir beam is formed when the immediate roof is relatively thick. The patterns of shield pressure and surface subsidence under different roof conditions are also examined. The shield working pressure under the Voussoir beam structure appears to be lower than that under the cantilever beam structure. The average horizontal distance behind the working coal face at which the maximum surface subsidence occurs is 92.1 m. On-site monitoring data are used to explain the causes of the unusual shield pressure and its relation to surface subsidence. Finally, guidelines to predict the shield pressure under similar conditions are provided. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since the beginning of spring 2022, successive landslides have occurred in the eastern pit slope of the Wolong Coal Mine in Qipanjing Town, Otog Banner, Inner Mongolia, which has adversely affected the mine's production safety. This study aims to reveal the deformation patterns and failure mechanisms of landslides. Firstly, this study establishes the stratigraphic structure of the eastern pit slope of the Wolong Coal Mine using extensive field geological surveys combined with unmanned aerial vehicle photography, drilling, and comprehensive physical exploration techniques. Indoor geotechnical tests and microscopic experiments reveal that rock mass typically exhibits the characteristics of expansibility and water sensitivity. Moreover, the mechanical parameters of the rock mass were determined using a combination of the window sampling method, the Geological Strength Index, and the Hoek–Brown strength criterion estimation theory. Finally, this study consolidates the previously mentioned insights and employs FLAC3D (7.0) software to assess the stress–strain characteristics of the excavated slope. The results indicate that the deformation mode of the Wolong open pit coal mine is the toppling failure of soft-hard-interbedded anti-inclined layered rock slopes. The unloading effect and rock expansion-induced softening lead to stress concentration at the slope corners and more substantial deformation, thereby accelerating upper slope deformation. The deformation and destabilization process of landslides is categorized into four stages: the initial deformation stage, the development stage of lateral shear misalignment, the development stage of horizontal tensile-shear damage, and the slip surface development to the preslip stage. This research offers valuable references and engineering insights for future scientific investigations and the prevention of similar slope-related geological hazards. [ABSTRACT FROM AUTHOR]

A large number of burnt rocks in some open-pit mines in Xinjiang, Inner Mongolia and Ningxia have a great influence on the blasting effect. For this kind of rock, through the analysis of physical and chemical changes, combined with ANSYS/LS-DYNA and PFC 2D numerical simulation software, a burnt rock model with multiple joint cracks and irregular distribution is constructed to simulate the blasting process of burnt rock under the combined action of stress wave and detonation gas. The results show that the fracture of rock mass affects the propagation of blasting cracks in the fracture area, resulting in stress concentration and stress hindrance. The action time of stress wave is reduced, and the energy of blasting gas is partially absorbed by the fracture, resulting in uneven stress on the burnt rock bench and seriously affecting the bench blasting effect. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To further promote dust control efforts in Chinese open-pit coal mines, this study focuses on the research of coal dust and rock dust produced by different explosions in the Haerwusu open-pit coal mine in China. By investigating the relationship between the physical and chemical characteristics of dust particles from explosions in open-pit mines and the wetting properties of dust, the main factors influencing the wetting properties of explosive dust are identified. This provides a theoretical basis for subsequent dust control work in open-pit coal mines. Simultaneously, to formulate more effective dust suppressants and reduce explosive dust pollution, this study conducts experiments on the surface tension, contact angles, and complex solution compatibility to select suitable surfactants. Ultimately, the effectiveness of the dust suppressants is evaluated through permeability experiments and indoor dust suppression experiments. The research findings are as follows: (1) The significant factors affecting the wetting properties of coal dust are the fixed carbon content and D50, while the significant factor affecting the wetting properties of rock dust is D50. (2) The formulated dust suppressants can increase the permeation height of coal dust by at least 10 times, increase moisture absorption by at least 4 times, and reduce the TSP concentration by at least 81.4%. [ABSTRACT FROM AUTHOR]

• A gas migration-diffusion model was constructed. • The optimization scheme of gas extraction parameters were discussed. • The effects of parameters on the extraction effect were investigated. Gas drainage is the main technical measure to prevent and control coal and gas disasters. Reasonable extraction parameters can improve extraction efficiency and reduce the risk of gas accidents. In order to further study the influence of extraction parameters on gas drainage effect, this paper combines COMSOL Multiphysics numerical simulation and field experiment to optimize the two parameters of intubation spacing and extraction negative pressure in goaf of 42,201 working face in Buertai Coal Mine, Inner Mongolia. The three-dimensional gas distribution model in goaf was established, and the COMSOL numerical simulation software was used for calculation. Combined with the field experiment, the influence of intubation spacing and extraction negative pressure on the extraction effect was obtained. The results show that in the range of 50 m-70 m, the drainage effect is ideal when the negative pressure is 12–18 kPa. [ABSTRACT FROM AUTHOR]

The Wuda coalfield in Inner Mongolia is a vital coal base in China, and it is the hardest-hit area for coal fires (spontaneous combustion of coal seams and coal gangue). Using gas chromatography–mass spectrometry, this work tested the concentration and analyzed the characteristics, distribution, sources, and health risks of polycyclic aromatic compounds (PACs) in the surface soil of the Wuda District, including the coal mine, coal fire, agricultural, and background areas. The soil of coal mine and coal fire area were heavily polluted with PACs, with mean concentrations of 9107 and 3163 µg kg−1, respectively, considerably higher than those in the agricultural (1232 µg kg−1) and background areas (710 µg kg−1). Alkyl polycyclic aromatic hydrocarbons (APAHs) were the dominant pollutants among these PACs, accounting for 60–81%. Alkyl naphthalenes and alkyl phenanthrenes are the primary pollutants in APAHs, accounting for 80–90% of the total amounts. Additionally, using the positive matrix factorization method, it can be concluded that the primary PAC sources are petrogenic sources, coal and biomass combustion, coal fires, and vehicle emissions. Finally, according to the cancer risk values of 16 PAHs, only the coal mine area showed a potential cancer risk. However, this result lacks a risk assessment of APAHs and underestimates the actual risk. The results of this study improved the understanding of PAC pollution in coal fire and surrounding areas and provided a reference for environmental and health risk investigations. [ABSTRACT FROM AUTHOR]

Evaluating the variations in terrestrial water storage anomalies (TWSA) associated with climate forcing and human activities in the Mongolian Plateau is crucial for assessing water scarcity and predicting potential pressures on water resources in the future. In this study, we assessed the impacts of climatic and anthropogenic drivers on the change in TWSA on the Mongolian Plateau by using the Independent Component Analysis (ICA) to examine Gravity Recovery and Climate Experiment (GRACE) based TWSA data and comparing the ICA modes with hydrometeorological data and statistical data related to human activities. The results showed that TWSA in the Mongolian Plateau has experienced significant depletion (−2.3 ± 0.62 mm/year) from 2002 to 2017, with a severe decline (−3.4 ± 0.78 mm/year) in Inner Mongolia, China, and a moderate depletion rate in Mongolia (1.44 ± 0.56 mm/year). The results of the statistical analysis indicated that climate change was the dominant driver for the decline in TWSA from 2002 to 2007, resulting in a decrease in TWSA in Mongolia and Inner Mongolia at rates of −5.17 ± 1.13 mm/year and −5.01 ± 2.0 mm/year, respectively. From 2008 to 2017, the intensity of human activities has increased in Mongolia, but climate-driven effects greatly offset the anthropogenic changes, leading to an increasing trend in TWSA in Mongolia during this period. Nevertheless, in Inner Mongolia, the anthropogenic water depletion, such as irrigation, coal mining, and grazing, outweighed the climate contributions on the variations in TWSA, causing the TWSA in Inner Mongolia to decline at a rate of 1.08 ± 0.54 mm/year during 2007–2011. [ABSTRACT FROM AUTHOR]

With the increasing proportion of open-pit coal mining in the coal mining industry in China, a series of potential safety hazards, environmental pollution, ecological damage and other problems caused by open-pit coal mining have attracted a great deal of attention. Scientifically determining the appropriate mining right scope of an open-pit coal mine can prevent various problems caused by coal mining from the source. In this study, according to the characteristics of open-pit coal mining and the environmental characteristics in arid areas, 15 indicators were selected and their weights were determined from the three perspectives of geological environment, social environment and ecological environment by using the AHP. Based on the spatial analysis function of ArcGIS, a digital evaluation model was established for the corresponding influencing factors, and a comprehensive evaluation model for setting the mining right range was constructed by superimposing the weights. Finally, four mining areas were identified within the study area in Wuhai, Inner Mongolia, and their ecological values were calculated to determine the mining area with the lowest ecological impact. [ABSTRACT FROM AUTHOR]

Over-exploitation of coal mines leads to surface subsidence, surface cracks, collapses, landslides, and other geological disasters. Taking a mining area in Nalintaohai Town, Ejin Horo Banner, Ordos City, Inner Mongolia Autonomous Region, as an example, Sentinel-1A data from January 2018 to October 2019 were used as the data source in this study. Based on the high interference coherence of the permanent scatterer (PS) over a long period of time, the problem of the manual selection of ground control points (GCPs) affecting the monitoring results during refinement and re-flattening is solved. A DInSAR-PS-Stacking method combining the PS three-threshold method (the coherence coefficient threshold, amplitude dispersion index threshold, and deformation velocity interval) is proposed as a means to select ground control points for refinement and re-flattening, as well as a means to obtain time-series deformation by weighted stacking processing. A SBAS-PS-InSAR method combining the PS three-threshold method to select PS points as GCPs for refinement and re-flattening is also proposed. The surface deformation results monitored by the DInSAR-PS-Stacking and SBAS-PS-InSAR methods are analyzed and verified. The results show that the subsidence location, range, distribution, and space–time subsidence law of surface deformation results obtained by DInSAR-PS-Stacking, SBAS-PS-InSAR, and GPS methods are basically the same. The deformation results obtained by these two InSAR methods have a good correlation with the GPS monitoring results, and the MAE and RMSE are within the acceptable range. The error showed that the edge of the subsidence basin was small and that the center was large. Both methods were found to be able to effectively monitor the coal mine, but there were also shortcomings. DInSAR-PS-Stacking has a strong ability to monitor the settlement center. SBAS-PS-InSAR performed well in monitoring slow and small deformations, but its monitoring of the settlement center was insufficient. Considering the advantages of these two InSAR methods, we proposed fusing the time-series deformation results obtained using these two InSAR methods to allow for more reliable deformation results and to carry out settlement analysis. The results showed that the automatic two-threshold (deformation threshold and average coherence threshold) fusion was effective for monitoring and analysis, and the deformation monitoring results are in good agreement with the actual situation. The deformation information obtained by the comparison, and fusion of multiple methods can allow for better monitoring and analysis of the mining area surface deformation, and can also provide a scientific reference for mining subsidence control and early disaster warning. [ABSTRACT FROM AUTHOR]

The Wuda Coalfield located in the Inner Mongolia Autonomous Region, North China is known as one of China's major source of prime coking coals and a site of well-researched and well-documented underground coal fires. The underground coal fire at the coal fire zone No. 3.2 is situated in the active coal mine of Suhai-Tu, located in the north westerly part of the Wuda Coalfield. The present paper investigates the impact of the underground coal fire on the coal seam No. 10 by application of coal petrographic methods, including detailed characteristic of macerals and other coal components, maceral analysis, microstructural analysis, and vitrinite reflectances performed on (1) coal grains lacking impurities, microfractures, dark oxidation rims, (2) on dark-rimmed vitrinite, as well as (3) on low-temperature semi-coke. The investigated coal seam No. 10 represents a high volatile A bituminous coal and is dominated by vitrinite, followed by inertinite with minor amounts of liptinite and by non-isotropic low-temperature semi-coke. The microstructure of the oxidatively and thermally altered coals is represented by (1) extensive non-tectonic microfissures and non-tectonic microfractures i.e., shrinkage microfractures, leading to defragmentation of coal grains, (2) dark oxidation rims observed at grain margins, non-tectonic microfissures and microfractures, and by (3) devolatilisation micropores. Random vitrinite reflectances measured in (1) coal grains lacking impurities, microfractures, and dark oxidation rims, and in (2) dark-rimmed vitrinite at non-tectonic microfissures and fractures reveal significant lateral variations. The presence of low-temperature semi-coke and its marked lower reflectance values are indicative of thermal alteration induced by the underground coal fire in the coal fire zone No. 3.2. The results obtained from the performed analyses of organic matter point to both low-temperature oxidation and low-temperature-pyrolysis processes. The applied coal petrological approach revealed characteristic changes to the coal's microstructure, its petrographic composition, as well as to optical properties induced by the underground coal fire. [ABSTRACT FROM AUTHOR]

The development of coal resources is necessary, but it has a huge negative impact on land, ecology, and the environment. With the increasing awareness of environmental protection and the requirements of related regulations, the design and practice of reclamation projects run through the mining life cycle and continue for a long time after the coal production. High-precision monitoring of mining disturbance and reclamation, quantifying the degree and time of vegetation disturbance and restoration, is of great significance to minimize the environmental effect of mining. Remote sensing, widely used as efficient monitoring tool, but there is not enough research on disturbance and reclamation monitoring taking into account large-scale areas and high temporal and spatial accuracy. Especially when mining sites remain unknown, how to distinguish the disturbance of coal mining and other human activities affecting the surface land cover has become a challenge. Therefore, this paper proposed a method to reconstruct the time series of mining disturbance and reclamation in a large area by using the POI (point of interest) and Landsat time series images using multiple buffer analysis methods. The process includes: (1) Retrieval of POI in the study area based on the public mining list using Python crawler, and buffering 100 km for preliminary extraction of potential mining areas; (2) Using spectral index mask and random forest algorithm to accurately extract the exposed coal on the Google Earth Engine (GEE) platform; (3) Buffering 10 km to identify the occurrence of disturbance and reclamation, using pixel-based temporal trajectory identification of LandTrendr algorithm under GEE. The method successful detect the change points of surface coal mining disturbance and reclamation in eastern Inner Mongolia of China. The results show that: (1) The method can effectively identify the extent of surface coal mining disturbance and reclamation, and the overall extraction accuracy is 81%. (2) Surface coal mining disturbance in eastern Inner Mongolia was concentrated in 2006–2011. By 2020, the total disturbed area is 627.8 km2, with an average annual disturbance of 18.5 km2, and the annual maximum disturbance to the ground reached 64.6 km2 in 2008. With the total reclaimed area being 236.3 km2, the reclamation rate is about 37.6%. This study provides a systematic solution and process for monitoring the disturbance and reclamation of surface coal mining in a large range with little known about the mines' location. It can effectively identify the mining disturbance and reclamation process which can also be extended to other areas, providing a quantitative assessment of mining disturbance and reclamation, which can support further ecological restoration decision-making. [Display omitted] • A remote sensing procedure of surface coal mine classification, disturbance and reclamation monitoring is developed. • Landsat, random forest, web scraping, and Google Earth Engine has been used to detect 73 surface coal mining sites. • 0.94% of the total study area has been disturbed by surface mining. • The developed procedure is able to reveal the surface coal mine reclamation pattern. [ABSTRACT FROM AUTHOR]

Double-roadway tunneling could mitigate the contradiction between mining production needs and tunneling speed, which is pivotal to the sustainable development of underground mines. However, it is very difficult to control the stability of a mining roadway on an adjacent working face suffering from strong mining disturbance due to double-roadway tunneling, especially at a large mining height working face. In order to control the stability of the return air roadway (RAR) 23205 of a strong mining roadway at working face 23205 in the Zhuanlongwan Coal Mine in Inner Mongolia, we carried out field monitoring, theoretical analysis, numerical simulations, and engineering practice to identify the main factors influencing the deformations and the stress distribution law of the surrounding rock in order to propose countermeasures for strong mining roadways. The results show the factors influencing the large deformation of strong mining roadways include large mining height, repeated mining, stress concentration due to the large coal pillar, and a small thickness of the anchorage layer in the roof. The stress peak in the central coal pillar caused by the first and second mining is 23.19 MPa and 27.49 MPa, respectively, and the stress concentration coefficients are 4.538 and 5.379, respectively. Countermeasures (pressure relief via large-diameter boreholes in the large coal pillar and long anchorage for roof reinforcement) were created to control the stability of a strong mining roadway, i.e., RAR 23205. Field measurements indicated that deformations in RAR 23205 could be efficiently controlled. The maximum deformation of the surrounding rock was 50 mm, which meets the safety and efficient production requirements of the coal mine. In addition, new roadway layout optimization and control countermeasures are put forward to control the stability of mining roadways. [ABSTRACT FROM AUTHOR]

Open-pit mining has caused extensive land destruction, including land abandonment and reduction in agricultural land, resulting in serious environmental problems. Ecological restoration and mine reclamation have become important components of the sustainable development strategies in Inner Mongolia, China. Therefore, the rehabilitation of mines and agricultural land is vital and has attracted widespread attention from the Chinese government. In this light, we reviewed the progress of mine restoration technologies in China in recent years and summarized the integrated technology of open-pit mine reclamation with microbial restoration technology as the core, ecological vegetation restoration as the essential, and soil restoration and improvement as the promotion. As a cost-effective and environmentally beneficial technique, combining the microbial recovery technology with vegetation and the recovery of vegetation and the improvement of the soil is widely recommended in the mining reclamation area. At the same time, we comprehensively analyzed the current status and progress of ecological restoration technology and put forward the development direction of green mining in the future. In conclusion, this review can provides guiding the sustainable development of green, ecological mines, as well as provide reference for mining reclamation and agricultural land restoration and other related fields. [ABSTRACT FROM AUTHOR]

The development and utilization of mining resources are basic requirements for social and economic development. Both open-pit mining and underground mining have impacts on land, ecology, and the environment. Of these, open-pit mining is considered to have the greatest impact due to the drastic changes wrought on the original landform and the disturbance to vegetation. As awareness of environmental protection has grown, land reclamation has been included in the mining process. In this study, we used the Shengli Coalfield in the eastern steppe region of Inner Mongolia to demonstrate a mining and reclamation monitoring process. We combined the Google Earth Engine platform with time series Landsat images and the LandTrendr algorithm to identify and monitor mining disturbances to grassland and land reclamation in open-pit mining areas of the coalfield between 2003 and 2019. Pixel-based trajectories were used to reconstruct the temporal evolution of vegetation, and sequential Landsat archive data were used to achieve accurate measures of disturbances to vegetation. The results show that: (1) the proposed method can be used to determine the years in which vegetation disturbance and recovery occurred with accuracies of 86.53% and 78.57%, respectively; (2) mining in the Shengli mining area resulted in the conversion of 89.98 km2 of land from grassland, water, etc., to barren earth, and only 23.54 km2 was reclaimed, for a reclamation rate of 26.16%; and (3) the method proposed in this paper can achieve fast, efficient identification of surface mining land disturbances and reclamation, and has the potential to be applied to other similar areas. [ABSTRACT FROM AUTHOR]

• Propose a Modified Landscape Disturbance Index. • Determine the spatial distribution of surface mining impact on grasslands. • The impact of surface mining on grasslands landscape ecology is heterogeneous. Coal mining and utilization have always been a great impact on landscape ecology. Many studies have identified the impact of surface mining through landscape changes, but the spatial distribution and extent of the impacts are considered less in existing studies. The objective of this study is to determine the spatial distribution and extent of the impact of surface mining on the Landscape Ecological Health (LEH) of semi-arid grasslands. The research area of this paper is Shengli surface mines, Xilinhot City, Inner Mongolia Autonomous Region, China. The main steps of the research method include LEH assessment, buffer analysis, Landscape Ecological Function Contribution Rate (LEFCR) and Modified Landscape Disturbance Index (MLDI) measurement. The results indicated that: 1) the theoretical reference range of the impact of Shengli surface mines on the semi-arid grassland LEH is 5 km. 2) The proposed MLDI can effectively monitor the disturbance of surface mining on landscape ecology. 3) The heavily affected area is mainly the open-pit landscape; the moderately affected area is mainly the dumping landscape and the mining area industrial square landscape, and the slightly affected area is mainly a small part of the dumping landscape and the surrounding grassland landscape of the mining area. The spatial distribution of the impact of surface mining on the landscape ecology of semi-arid grasslands is heterogeneous, which should be taken into account in landscape ecological management, restoration, and planning. This paper may serve as a reference for the study of the disturbances and impacts of human activities on landscape ecology. [ABSTRACT FROM AUTHOR]

Quantitative assessment of the terrestrial water storage (TWS) changes and the major driving factors have been hindered by the lack of direct observations in Inner Mongolia, China. In this study, the spatial and temporal changes of TWS and groundwater storage (GWS) in Inner Mongolia during 2003–2021 were evaluated using the satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) and the GRACE Follow On combined with data from land surface models. The results indicated that Inner Mongolia has experienced a widespread TWS loss of approximately 1.82 mm/yr from 2003–2021, with a more severe depletion rate of 4.15 mm/yr for GWS. Meteorological factors were the driving factors for water storage changes in northeastern and western regions. The abundant precipitation increased TWS in northeast regions at 2.36 mm/yr. Anthropogenic activities (agricultural irrigation and coal mining) were the driving factors for water resource decline in the middle and eastern regions (especially in the agropastoral transitional zone), where the decrease rates were 4.09 mm/yr and 3.69 mm/yr, respectively. In addition, the severities of hydrological drought events were identified based on water storage deficits, with average severity values of 17 mm, 18 mm, 24 mm, and 33 mm for the west, middle, east, and northeast regions, respectively. This study established a basic framework for water resource changes in Inner Mongolia and provided a scientific foundation for further water resources investigation. [ABSTRACT FROM AUTHOR]

• A dynamic two-stage SBM model with non-discretionary variables is proposed. • China's CPLR efficiency under four scenarios of extreme temperatures is measured. • The influences of extreme temperatures on the CPLR efficiency are highlighted. • A comparative analysis of CPLR efficiency under four scenarios is provided. With the influence of climate changes resulting in more extremely days, we might expect to face a rise in associated coal productivity losses and land destruction. Numerous studies have focused on measuring the efficiency of coal production system. Yet scant studies have considered their internal structure, reconstructed lands, and especially the impact of extreme temperatures. Then, this paper divided such a system into stages of coal production (CP) and land reconstruction (LR), named the CPLR system. This study proposes a modified two-stage dynamic slacks-based measure model with non-discretionary variables for measuring the CPLR efficiency under four scenarios of extreme temperatures. The results are as follows. (1) The CPLR system for 24 provinces under four scenarios spanning 2012 to 2017 had relatively low efficiency except for Fujian, Inner Mongolia and Sichuan, which is mainly caused by the bad performance of the LR system. (2) Extreme temperatures must be considered in measuring CPLR efficiency and its stage efficiency, or otherwise the underestimation of CPLR efficiency and CP efficiency will become in 18 provinces. The negative impacts of extreme temperatures on the efficiency of reconstructed lands and raw coal production should be noticed, especially for Anhui. [ABSTRACT FROM AUTHOR]

Groundwater (GW) is an important source of freshwater in arid and semiarid areas. Some important industrial activities, such as coal mining, also consume GW. There have been few studies evaluating GW quality in the Selian coal mining area of Inner Mongolia. This study aimed to identify the hydrochemical phases and the sources of main ions in the GW of the Selian coal mining area. Water quality analysis was performed on 20 shallow GW samples collected from the study area. Statistical correlation analysis was performed on these water quality data. The quality of irrigation water was evaluated based on water quality indices such as the sodium absorption rate and sodium percentage. The risk of nitrate pollution in the study area to human health was evaluated by GW nitrate content. The results show that the dominant GW chemistry types in the study area are the mixed and Ca–HCO3 types. Correlation analysis indicates that rock weathering and leaching are the main natural drivers of GW hydrochemistry in this area. The irrigation risk analysis shows that GW in this area can be used for irrigation, although some caution is needed. The human health risk assessment shows that GW nitrate pollution poses more risk to children than to adults by a factor of 1.168. It is recommended that centralized treatment of drinking water is the optimal approach to managing this risk. The results of this study can act as a reference for the rational use of GW and for control of nitrate pollution in this area. [ABSTRACT FROM AUTHOR]

Roof-breaking characteristics and ground pressure behavior of the coalface are instrumental in guiding deep Jurassic coal seam mining, in particular in the Shaanxi and Inner Mongolia regions of China. A thick-plate mechanical model (TPMM) of the main roof was developed and applied to the case study of 21102 first-mined coalface (FMC) of the Hulusu Coal Mine (HCM) in the Hujirt Mining Area (HMA), China. A theoretical analysis performed via the developed model revealed that the first and periodic breaking intervals of the main roof were 40.6 and 25.0 m, respectively. The roof failure occurred in the tensile mode, was controlled by the internal stress σ x in the rock strata, and started from the center of the long side with the fixed support in the goaf. The field measurement of roof weighting was also performed for the coalface advance from zero to 400 m. The measurement results showed that the first weighting average interval was 41.4 m, and the average interval of periodic weighting was 22.0 m, which agreed with the theoretical calculation and proved the proposed model's feasibility. Finally, the frequency distribution features of the hydraulic support working resistance in the FMC were analyzed statistically. The results showed that the ZY10000-16/32D supports could adapt to the mining geological conditions of the FMC. However, the margin of the rated working resistance of supports was still small. Thus, roof management enhancement during the mining process was strongly recommended. These research findings could offer theoretical guidance for safe and high-efficiency production in the coal mines under similar geological conditions. [ABSTRACT FROM AUTHOR]

Coal seam impact risk assessment is the premise of coal mine safety, which can reduce the occurrence of underground impact pressure accidents and directly affect the safety, coal production, economic and social benefits of coal mining enterprises. In order to evaluate the impact risk of coal seams more reasonably and comprehensively, and consider the weights of different influencing factors on the impact risk of coal seams, the neural network model is proposed to evaluate the impact risk of coal seams. Mining depth, impact tendency, geological structure and mining technology are selected as the influencing factors of coal seam impact risk. Each influencing factor contains different evaluation indices, a total of 18. The 18 evaluation indices and the impact risk level are normalized and quantified. The BP neural network model for evaluating coal seam impact risk level is established, and the impact risk of 2-1 coal seams in a mine in Inner Mongolia is comprehensively evaluated and analyzed in this study. The results show that the BP neural network model can represent coal seam impact risk level well. The application of the BP neural network model to evaluate coal seam impact risk level has the characteristics of high precision, fast calculation speed and less artificial calculation, which provides an efficient and convenient method for the evaluation of coal seam impact risk. [ABSTRACT FROM AUTHOR]

Abstract: The Yimin Ge-coal deposit, located in the Yimin coalfield, Inner Mongolia, is the third largest Ge-rich coal deposit in China just after the Lincang and Wulantuga Ge-coal deposits. Based on the coal and non-coal samples recently collected from the Wumuchang coal mining district in the Yimin Ge-coal deposit, this paper reports some new data on the mineralogical and geochemical characteristics of the Yimin high-Ge coals, and provides some new evidence for the possible mode of Ge enrichment in the Yimin coals. Mineralogical analyses were performed by means of Powder X-ray diffraction (XRD). Major and trace element concentrations were determined by inductively coupled plasma atomic-emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Element affinities were determined by Pearson's correlation analysis. The studied coals fall within the coal rank between sub-bituminous A and high volatile bituminous C, with relatively high moisture content, high volatile matter yield and low to medium ash yield. Quartz and kaolinite are the main mineral matters in the Yimin coals, with small amounts of pyrite and traces of microcline. Common pyrite and As-bearing pyrite occurring in the Yimin coals show an epigenetic origin. The epigenetic precipitation of kaolinite, quartz and As-rich pyrite (with Ge, and other trace elements) in the Yimin coal fractures may be caused by activities of both hydrothermal and low temperature fluids. Compared to common Chinese and worldwide coals, the Yimin coals are markedly enriched in Ge (43mg/kg), As (155mg/kg), and W (9.84mg/kg) and slightly enriched in Pb (22mg/kg) and Hg (0.24mg/kg). Most of the elements (e.g. Al, K, Sc, Ti, V, Cu, Ga, Sn, Th and REEs) in the studied coals present an aluminosilicate affinity as deduced from their obvious positive correlation with Al and ash yields. High correlation coefficients of As and Hg with Fe and S indicate a sulfide affinity of these elements in the Yimin coals. Germanium, B, Mo, and W in the studied coals show an organic affinity and a partial sulfur affinity as deduced from their negative correlation with Al and positive correlation with S, respectively. The preliminary and possible model for Ge enrichment in the Yimin Ge-coal deposit was that Ge was carried by hydrothermal fluids and then these fluids were incorporated in the water existing in the upper porous conglomerates and percolate in the top of the coal seam, where Ge was trapped by organic matter and finally enriched in an early diagenetic stage (humification–gelification). [Copyright &y& Elsevier]

Coal seam water injection is one of the important technical means to prevent mine disasters. It can effectively change the mechanical properties of coal, prevent dust, coal and gas outburst, and reduce gas concentration. In order to expand the range of coal seam water injection, make coal seam water injection more effective in wetting coal mass, and determine the effective type of ionic surfactant required for coal seam water injection, triaxial seepage experiments and spontaneous imbibition experiments are conducted on the long flame coal samples from Houwenjialiang Coal Mine in Ordos City, Inner Mongolia Autonomous Region, China in this paper. Moreover, the effects and mechanisms of different ionic surfactants on the seepage and wetting stages of coal seam water injection are studied, which provides a theoretical basis for on-site coal seam water injection. After analysis and discussion, it is found that the influence of cationic surfactants on the seepage stage of coal seam water injection first decreases and then increases while the influence of anionic surfactants on the seepage stage of coal seam water injection shows a gradually increasing trend. Furthermore, both cationic and anionic surfactants show more significant wetting effects as the concentration of the surfactants increases. In addition, the adsorption of cations to coal molecules is stronger than that of anions, and the water solubility of cations is better than that of anions. [ABSTRACT FROM AUTHOR]

To better understand water inrushes originating from shaft-freezing holes, the hydrogeological conditions and water source were analyzed for a typical inrush case in the Yingpanhao coal mine in western China. The mechanism of this new type of water inrush was identified by considering the stratum movement caused by mining, the concentric annular channels of freezing holes, and the dynamic recharge of multiple aquifers. A new risk assessment model and corresponding grouting method were developed and the problems involving the prediction of water inrush and selection of the optimum grouting position were described. Detailed guidelines for grouting, including the layout of injection boreholes, slurries, grouting pressure and stopping criteria, were proposed. A grouting case targeting this type of water inrush in the Yingpanhao coal mine was introduced. Field studies indicated that open, concentric annular freezing hole channels provide favorable conditions for groundwater migration. The proposed method may effectively inhibit groundwater migration in multiple aquifers and prevent water inrushes through shaft freezing holes and provides an appropriate framework for water inrush prevention for similar mining areas in western China. [ABSTRACT FROM AUTHOR]

A small-pillar gob-side roadway showed rockburst appearance during the mining of a gob-side working face located in the Shaanxi-Inner Mongolia mining area. This study examines the 2202 gob-side working face of a coal mine in Inner Mongolia as a case study. A stress evolution model was built for the static-stress spatial islands formed by drainage regions and goafs based on the spatial relationships between drainage regions and goafs. The average microseismic frequency and energy of the high-stress zone of spatial islands were at least 1.37 times of those of other zones, validating the presence of spatial islands. The dynamic and static load effects of working face squaring were obtained based on the evolution of the stope roof as well as changes in microseismic data. Microseismically active zones were advanced to 200 m–300 m on working faces. The rockbursts induced by high static loads and dynamic and static loads formed by spatial islands and squaring were calculated. According to calculation results, the critical stress concentration value under high static loads was 3.27; the critical static stress concentration value under dynamic and static loads was 1.81. The superposition of drainage boundary stress, goaf lateral stress, and lead stress might reach the critical stress concentration under dynamic load disturbances, causing rockbursts. A stress adjustment scheme was established, including overall hydraulic fracturing of the external roof of the drainage region, reduction of stoping speed, and pressure relief of large-diameter boreholes. The stress adjustment scheme was implemented on-site and supplemented by monitoring and early warning methods to safely advance by the first squaring region. [ABSTRACT FROM AUTHOR]

The development and use of intelligent drilling rigs make it available to obtain accurate lithology data of blast drilling. In order to make full use of drilling data to improve blasting efficiency, the following research was carried out. First, a database is established to manage and store the blast hole data recognized by the intelligent drill. Secondly, the blast hole lithology data is taken as a sample, and the inverse distance square method is used to interpolate the blasting range's solid elements to generate a three-dimensional solid model of the blasting rock mass. Afterward, the blasting range polygon and stope triangle grid are used successively in the solid model to obtain the cut 3D solid model of the blasting rock mass; finally, the blast hole charge is calculated based on the cut 3D solid model of the blasting rock. The C++ programming language is used to realize all the blast hole charge amount processes based on the three-dimensional solid model of the blasting rock mass. With the application example of No. 918 bench blasting of Shengli Open-pit Coal Mine in Xilinhot, Inner Mongolia, the blast hole charge amount in the blasting area is calculated and compared with the results of single hole rock property calculation, the results show that the blast hole charge calculated by three-dimensional rock mass model can be effectively reduced. [ABSTRACT FROM AUTHOR]

Aiming at the problem of mining coal resources under the Yuxing Mine Ecological Park in Inner Mongolia, China, we adopted a continuous mining and continuous backfilling (CMCB) cemented-fill mining method; based on the systematic description of the mining and backfilling craft of the CMCB mining process, comprehensive use of theoretical analysis, numerical simulation, and similar simulation test methods to analyze the control mechanism of overlying strata. By establishing the mechanical model of roof movement for the CMCB mining, the roof deflection curve equation is deduced, and the roof instability criterion is put forward based on the maximum tensile stress criterion. Numerical simulation showed that the stress curve at the shallow part of the roof fluctuates up and down in a "w" shape, the stress curve of the upper surrounding rock sinks slowly, and the coal pillars and filling bodies are alternately loaded during the staged mining process to jointly limit the movement of the overlying strata. The similar simulation test results showed that the roof has no structural damage, the roof cracks are not obvious, and the overlying strata control effect is good. On site tests showed that the CMCB mining method can effectively limit the movement of the overlying rock in the stope, control the surface subsidence of the ecological park, and increase the recovery rate of coal resources. It can provide a reference for the development of coal resources and ecological protection in a fragile environment. [ABSTRACT FROM AUTHOR]

Short wall mining technology is an important method to coal resource mining in the United States, Australia and other countries, and also one of important methods to boundary coal resource recovery in China. Short wall mining technology through leaving a large number of coal pillars to support and control roof, induces a series of accidents, such as large area roof suspended, collapse and shock, which restricts the further popularization and application of short wall mining technology seriously. By improving the existing short wall mining technology, the article proposed short wall continuous mining technology with full roof falling, and designed measures to control roof. The main research work is as follows: (1) By reducing and eliminating coal pillars in mining section as much as possible, including entry protecting pillar and pillar between caverns, also ensured stability of roof during mining period at the same time; after mining, roof can be collapse, to prevent large area roof suspended and collapsed inducing shock accidents; mining process and equipment of short wall continuous mining technology with full roof falling, were designed comprehensively. (2) Measures to control roof of short wall continuous mining technology with full roof falling are designed, using self-moving hydraulic support to control roof of mining cavern, anchor bolt and cable to ensure branch and cross entries stable during mining period, and forced caving technology to control large area roof suspended; (3) Short wall continuous mining technology with full roof falling and roof control measures were successfully industrialized in 42,210 boundary coal face of Yujialiang coal mine, which belong to Shenhua energy group in Inner Mongolia. The research result is significant to enrich and develop short wall mining technology. [ABSTRACT FROM AUTHOR]

There are many surface coal mines located in Inner Mongolia, which has dry and scarce topsoil, and the selection of topsoil alternatives is key to coal-mined land reclamation. This study used the largest surface coal mine in the Holonbuyr grassland as the experimental site. The soil of layer II (loess) and layer III (mild clay) under the local topsoil, which has a high clay content and good texture, has the potential to be a substitute for topsoil. To reduce its viscosity and improve its nutrients, soil amendments mixed with organic matter, such as corn stalk and sheep and cattle manure and microbial agents, were added to four mixed substrates with different formulas. Twelve topsoil alternatives were produced and compared for further research. The results show that (1) by mixing a variety of substrates, topsoil alternatives can fully meet the alfalfa (Medicago sativa L.) growth requirement. (2) The addition of exogenous organic matter and microbial agents could significantly increase the nutrient content and the number of microorganisms in the soil, thereby increasing the plant height of alfalfa (Medicago sativa L.) and the average dry mass of the aboveground and underground parts [ABSTRACT FROM AUTHOR]

Asymptotically correct simultaneous confidence bands (SCBs) are proposed in both multiplicative and additive form to compare variance functions of two samples in the nonparametric regression model based on deterministic designs. The multiplicative SCB is based on two-step estimation of ratio of the variance functions, which is as efficient, up to order n - 1 / 2 , as an infeasible estimator if the two mean functions are known a priori. The additive SCB, which is the log transform of the multiplicative SCB, is location and scale invariant in the sense that the width of SCB is free of the unknown mean and variance functions of both samples. Simulation experiments provide strong evidence that corroborates the asymptotic theory. The proposed SCBs are used to analyze several strata pressure data sets from the Bullianta Coal Mine in Erdos City, Inner Mongolia, China. [ABSTRACT FROM AUTHOR]

Water-bearing structures in front of coal mine shaft drivages require effective advanced prediction. Based on the characteristics of coal field logging curve carrying rich geological information, it is introduced into the advanced prediction of water-bearing bodies in mine shafts. At the same time, mine geophysical prospecting technology, such as the DC resistivity method, can accurately and effectively track and detect geological conditions during mine shaft drivage. The proposed advanced prediction method of the borehole-ground electrical method based on the detailed interpretation of logging curves was experimentally studied using physical simulations of the detailed interpretation of water-bearing rock strata in logging data and geophysical advanced detection simulations of water-bearing structures in mine shafts. By constructing a physical model of the mine shaft drivage, the change in the water content of the rock strata is simulated by adding water to sand and gravel, and the apparent resistivity logging in a borehole is simulated. The water-bearing characteristics of the model under different water content conditions are interpreted by using 3-D visualization technology, and it is concluded that the change law of the electrical characteristics of sand and gravel after adding water is a logarithmic function relationship. Then, based on the results of the detailed interpretation of the logging curves, a model experiment using the DC resistivity method of ground-borehole joint advanced detection is carried out, and the response characteristics of changes in the model water diffusion resistivity are accurately detected. In addition, a shallow geological borehole is constructed in the field. Water injection in the borehole causes anomalous changes in the electrical properties of the strata around the borehole and simulates water-bearing structures at different depths and layers, which verifies the effectiveness of the borehole-ground electrical method in detecting water-bearing structures in front of mine shaft drivages. The simulation results show that the advanced prediction method of borehole-ground electromagnetic technology based on the interpretation of logging curves enhances the effectiveness and detection efficiency of advanced detection and prediction of the water-bearing characteristics of rock strata. Based on the logging curve, the water-bearing characteristics of the strata in front of a coal mine shaft drivage in the Dongsheng coalfield in Inner Mongolia are interpreted in detail, and the provided anomalous target areas can provide reliable guidance for advanced detection using the borehole-ground electrical method in the future. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of fracture evolution of surrounding rock with different supporting conditions during excavation period in Hulusu coal mine, Inner Mongolia, China. Fractures of surrounding rock were measured by borehole images obtained with a digital panoramic borehole camera, and surface displacement of roadway was measured using the intersection point method. Based on the rock properties, original support method and constructional process of bolter miner, a simple and fast support system was proposed, which realized the complete parallel operation between bolt support and coal cutting. According to the data obtained from field monitoring and construction situation, the array pitch was extended from 1.0 m to 1.5 m gradually. Field measurements indicated that the overall effect of roadway under new support was more satisfactory than under original support, with no exception in all the five test stages. When the array pitch extended up to 1.5 m, the roof and rib convergence were 11 mm and 16 mm, a reduction of 66.7% and 57.9%, respectively. Under new supporting condition, fractures were distributed only within the bolt anchorage zone and both the number and opening of fractures were small. By contrast, under original supporting condition, fractures were distributed both in and out of the bolt anchorage zone. New support can make full use of deep strata by constructing thick anchorage rock beam, and large displacement of shallow strata can be inhibited through small displacement of deep strata. The realization of co-movement between large-small displacements ensures the safety control of roadway. New support can greatly improve support efficiency, providing a solution to the imbalance between excavation speed and production needs widely existing in coal mines producing 10 million tons a year. New support has already been successful applied in another roadway with top coal in Hulusu coal mine. [ABSTRACT FROM AUTHOR]

With the deployment of China's energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf. [ABSTRACT FROM AUTHOR]

Coal mining often brings negative impacts to land and eco‐environments. How to quantitatively evaluate this impact at a regional scale, and assess its related influences in mining and nonmining areas from an ecological viewpoint is important and a challenge. The Shendong Mining Area (SMA) at the junction region of Shaanxi Province and Inner Mongolia Autonomous region in northern China is a typical semi‐arid region. Remote sensing (RS) and Geographic Information System (GIS) were used to construct an ecosystem service measurement and evaluation index system in a typical high‐intensity coal mining area. Ecological Capital was estimated using remote sensing and statistical data from 2005, 2010 and 2015. The results show that (a) EC distribution has gradually increased from southeast to northwest (with an average annual growth rate of 2.32%); (b) water and soil conservation are the largest among ecosystem service functions, and the EC per unit area for the shrub ecosystem is the highest; and (c) the EC within the SMA grew steadily with an average annual growth rate of 3.09%. We can conclude that under high‐intensity mining, EC has not decreased, and the EC growth rate in some mining areas were even greater than nonmining areas, indicating that underground mining impacts were under tolerable threshold in this region. Through the remote sensing quantitative evaluation model, this article reveals the impact of regional ecological assets under different mining intensity, and provides an important basis for evaluating regional sustainable development and ecological environment management. [ABSTRACT FROM AUTHOR]

The Gaojialiang Coal Mine in Inner Mongolia in China was used as an example to investigate the process of chain pillar and gateroad failure in the lower coal seam under the effect of an irregular residual coal pillar in the upper close‐distance coal seam. The results indicated that after the longwall face in the lower coal seam retreated through the area under the large irregular residual coal pillar in the upper coal seam, the bearing area of the residual coal pillar decreased and the roof pressure continuously concentrated in the elastic core area of the residual coal pillar. Isolated triangular slab rock was formed above the triangular residual coal pillar, and the weight of the overlying strata was transferred downward through the triangular slab rock. When the chain pillar under the residual coal pillar was destroyed due to loading that exceeded its carrying capacity, the upper triangular slab rock rotated and sank, which resulted in the intensification of the concentrated stress in the solid rib of the gateroad in the lower coal seam. Based on the analysis, it is suggested that in the design of a longwall system, a gateroad under an isolated residual coal pillar in the upper coal seam should be avoided when mining in close‐distance coal seams. [ABSTRACT FROM AUTHOR]

• Element geochemistry in coals varies notably in a laterally correlated coal seam. • Various geological factors are responsible for the difference in the elemental geochemistry of the coals. • Some critical metals including REY are redeposited within the coal section as a result of acidic leaching. • The Datanhao coal seam has potential in industrial utilization of certain critical metals. This paper discusses the modes of occurrence of critical elements and their origins in the studied coal and associated rock samples (partings and roof strata) from the Datanhao coal mine, Daqingshan Coalfield, Inner Mongolia, northern China. The studied coals are enriched in trace elements including Zr, Hf, Th, Be, F, Zn, Ga, Nb, Mo, Cd, In, Sn, Ta, Hg, W, Pb, and rare earth elements and Y (REY). Zirconium, Nb, Ta, and Hf are largely associated with anatase in the studied coal and non-coal samples. The main carriers of REY, Th, and U in both coal and non-coal samples are Ca-bearing REE-phosphate minerals, most likely monazite, although U is partly associated with organic matter. Fluorine in the Datanhao coals is mainly associated with kaolinite. Most partings identified as volcanic ash-derived tonsteins from the Datanhao Mine exhibit negative Eu anomalies that, along with the common presence of equant-shaped euhedral volcanic quartz (beta-quartz), indicate a felsic volcanic source located in the Xing'an-Mongolia Orogenic Belt. Other probable sources of clastic material into the basin include the pre-Cambrian granites from the adjacent uplands, which may be responsible for the light rare earth element enrichment of the studied deposits, and associated metamorphic rocks from the adjacent uplands. Owing to acidic hydrothermal fluids, which are most likely related to the Yanshanian (Jurassic to Early Cretaceous) intrusive activity and/or low-temperature basinal waters circulating within the coal-bearing unit during the epigenetic stage, most of the coal benches from the Datanhao mine are also relatively enriched in middle rare earth elements. On the other hand, some coal and non-coal bench samples from the middle Datanhao section are enriched in heavy REE. This, along with the presence of abundant syngenetic or early diagenetic carbonate minerals, indicates deposition in an episodic alkaline environment, the origin of which is mostly probably attributed to evaporation and/or saline water inputs resembling a playa lake environment. As the concentrations of Zr, Hf, Nb, and Ta are all close to or higher than the respective industry cut-off grades or standards for these critical elements, the Datanhao coal seam has potential economic significance for these as an important by-product of the coal mining. [ABSTRACT FROM AUTHOR]