Xinglongzhuang Coal Mine Research Articles

Investigating a three-dimensional convolution recognition model for acoustic emission signal analysis during uniaxial compression failure of coal

Acoustic emission predicts coal sample failure, vital for early warnings and monitoring. The study emphasizes using acoustic emission to predict coal sample failure patterns and establish a discriminative model for monitoring. It employs a lightweight 3D convolutional model combining DenseNet with Group Convolution (GC) and the "squeeze-and-excitation" (SE) module. Coal samples from Xinglongzhuang Coal Mine underwent uniaxial compression, and a subset of experiments with prominent features was selected. The resulting acoustic emission parameters were then transformed into spatiotemporal image sequences for input to the model. Successfully identifying hazardous coal damage stages, all four network structures (DenseNet, DenseNet + GC, DenseNet + SE, DenseNet + GC + SE) achieved over 98.29% predictive accuracy in verification samples. The model exhibited a recall rate of over 98.02% for high-risk samples, effectively capturing spatiotemporal information. DenseNet + GC + SE showed a probability distribution focusing on different risk levels. By integrating group convolution and SE modules, this model significantly reduced both model and time complexity while preserving precision, enhancing efficiency. It effectively discerns diverse acoustic emission features through group convolution and evaluates their significance using the SE module. Compared to the traditional C3D neural network, this model greatly reduces complexity and time requirements while improving efficiency in distinguishing between various damage stages.

Characteristics of labile organic carbon fractions under different types of subsidence waterlogging areas in a coal mining area: A case study in Xinglongzhuang Coal Mine, China

The restoration of subsidence waterlogging areas has the potential to facilitate carbon accumulation in coal mining areas with high ground water tables. However, the soil organic carbon (SOC) and labile organic carbon (LOC) have not been sufficiently investigated in different types of subsidence waterlogging areas. In this study, SOC and LOC fractions, including light fraction organic carbon (LFOC), particulate organic carbon (POC), and dissolved organic carbon (DOC) within 0–50 cm soil profiles, were determined in a reference cropland (RC) and three types of subsidence waterlogging area in Xinglongzhuang Coal Mine, Shandong Province, China, including an aquaculture waterlogging area (AWA), deep waterlogging area (DWA) and shallow waterlogging area (SWA) with water depths of 1.8, 3.2, and 0.65 m, respectively. Compared with RC, SOC and LOC decreased by 4.13%, 25.03%, and 77.91% in SWA, DWA, and AWA, respectively. The largest depletion was in the 0–10 cm layer, indicating that there was a time lag for the recovery of the total functional pools of SOC after subsidence. The lability of POC was highest among the three types of LOC fractions, indicating that mining subsidence triggered soil redistribution and impacted on carbon accumulation. With comparatively little soil profile interference in DWA and SWA, the lability of LFOC and POC decreased with soil depth, while the DOC increased. There was a large discrepancy in AWA, with the lability of LOC fractions fluctuating because of soil disturbance by intensive engineering. The LOC fractions were closely associated and correlated with soil properties, especially total nitrogen (TN) and total phosphorus (TP). Restoration and management of the subsidence waterlogging areas have a vital impact on the SOC pool. It was concluded that shallow water and a natural geomorphology-based topography, with little soil disturbance, well-developed vegetation communities, and continuous monitoring of soil and water properties would facilitate the carbon accumulation process.

Strata Movement and Mining-Induced Stress Identification for an Isolated Working Face Surrounded by Two Goafs

Solutions for the maintenance of safety in an isolated working face has not been well achieved; this is attributed to its unique overburden structure and the strong mining-induced stress during the advancement. This paper is devoted to filling this research gap and is based on the case study of LW 10304 in the Xinglongzhuang Coal Mine, in China. The overburden structure and stress distribution characteristics of this isolated working face were theoretically investigated, followed by the development of a comprehensive identification method. The research results showed the following: (1) The overburden strata of LW 10304 is in the form of a short “T” shape and the stress increment is featured with the overall “saddle” shape before the extraction of the isolated working face. During this period, the lower key strata and main key strata affect the stress level at the two ends and the central part of the working face, respectively; (2) Both the frequency and energy of micro-earthquakes in the working face account for more than 95%, which is positively correlated with roof damage and rib spalling, associated with some overlaps between the damaged zones; (3) The fracture movement of inferior key strata near the coal seam plays a dominant role in affecting microseism activity and mining-induced stress. The microseism energy attributed to roof breakage accounts for 43.34% of the overall energy; (4) A comprehensive indexing system, covering microseism frequency, microseism energy, and support resistance, was established to identify the mining-induced stress intensity of the isolated working face. The early warning efficiency of the “strong” degree of mining-induced stress is 0.94, which is believed to provide an option for other isolated working faces with similar geological and mining conditions.

Study on comprehensive evaluation of environmental pollution treatment effect in coal mine subsidence area: taking Xinglongzhuang mining area of Yanzhou energy as an example.

In order to explore the effective evaluation method of environmental pollution treatment effect in China's coal mine subsidence areas, based on the literature review and analysis of current situation, combined with the reality of environmental pollution treatment (EPT) in China's coal mine subsidence areas, this paper selected four categories, including a total of 21 evaluation indicators, and drew lessons from the latest research results in relevant fields to construct the spatial niche suitability model of comprehensive evaluation of environmental pollution treatment effect in coal mine subsidence area. Taking the collapse area of Xinglongzhuang coal mine of Yanzhou energy as an example, the comprehensive evaluation and application of environmental pollution treatment effect in coal mine subsidence area were studied. It is found that the environmental pollution treatment effect of the mining area has increased from moderate pollution (level III) in 2012 to mild pollution (level I) in 2020 within 9years. The environmental pollution treatment effect has a rapid improvement relatively, but its growth rate has decreased year by year since 2016, and the environmental pollution indicator is still at a high level. Therefore, environmental pollution treatment in the subsidence area is still a long-term task of Dongtan coal mine. The research results of this paper provide an effective quantitative analysis method for the evaluation of environmental pollution treatment effect in coal mine subsidence area, which is conducive to the continuous improvement of environmental pollution treatment effect in mining area.

Identification for Abutment Stress by Drilling Cuttings

The concentration of abutment pressure acting on coal seams induced by mining is a key factor to trigger rock burst. Understanding of abutment pressure or stress concentration is fundamental in preventing and controlling rock burst. The influence on abutment pressure fluctuation caused by the inhomogeneity of coal seams needs to be considered, but it is difficult to obtain by the present usual ways such as acoustic transmission, electromagnetic wave transmission, etc. In this article, the relationship between the amount of cuttings drilled in a coal seam and stress level was analyzed by considering the effect of drilling cutting expansion, and the drilling cutting test was carried out in Xinglongzhuang Coal Mine, Shandong Energy Ltd. It is found that the amount of cuttings drilled is positively related to the degree of stress concentration in both the plastic fracture zone and elastic zone. The amount of drilling cuttings is closely related to the roof weighting. In addition, the irregular fluctuation of drilling cuttings is an approximate map of distribution of stress concentration because of the non-uniformity of cracks and other defects in the coal seam. In order to meet the need of rock burst prevention by accurate pressure relief in high-stress zones, enough boreholes are needed.

The optimal framework and model to balance underground coal mining and cropland protection in Jining, eastern China

Coal and cropland resources play a vital role in energy safety and grain supply, respectively. However, the social growth that is driven by coal mining is followed by cropland damage, reductions in grain yields, and human-land conflict, all of which impede the sustainable development of coal mining and food safety. Thus, finding a way to optimize both coal mining and farmland protection in the coal-cropland overlapping area is crucial. In this paper, we constructed theoretical and empirical models to analyze the impact of the working face width on cropland with non-full subsidence based on the extent of cropland damage due to land subsidence caused by mining. Taking the Jining Coalfield with its high groundwater table as an example, this critical land subsidence was discussed based on the groundwater level (reclamation timing), suitable groundwater depth of crop growth, and coal mining efficiency. In addition, the reasons for surface ponding were analyzed caused by underground coal mining. The results showed that the surface ponding's anthropogenic item and internal factors are mining-induced land subsidence and the high groundwater table, respectively. These joint factors raise the groundwater level and lead to grainland damages which can be divided into four categories based on their extents (no effect, slight-reduction in yield, moderate-reduction in yield, and no harvest). Critical subsidence caused by mining width could optimize the groundwater depth or cropland damage. The calculated results from both models of the eight coal mines showed that the average mean deviation was 3.93%. The calculated results from the models were reliable, while the empirical model had fewer parameters and an easily calculable simple formula. The proposed optimal framework verified that the mining width needed to be reduced to 134m, 126m or 116m, 112m based on the groundwater depth or the damaged farmland in the Xinglongzhuang Coal Mine. The optimal framework will be of great significance for providing scientific references as to why the sustainable development of coal mining and grainland protection has been chosen.

Field study on the improvement of coal gangue filling using dynamic compaction.

In this study, dynamic compaction method was used to treat the gangue hill of the Xinglongzhuang coal mine in China, and the deep compaction of deep coal gangue was examined. The crushing characteristics and improving depth of coal gangue filling under different dynamic compaction conditions were determined. Dynamic compaction tests with different tamping energy were performed to improve the coal gangue filling. In addition, dynamic penetration tests and the foundation bearing capacity were conducted. The relationship between the tamping energy and improvement was investigated, and the optimum tamping energy, number of tamping blows, improving depth, and other dynamic compaction parameters and filling bearing characteristics were obtained. The field test results show that with increasing number of tamping blows, compaction induced deformation gradually decreased and begins to stabilize, while the optimum number of tamping blows increases with increasing ramming energy. The optimum number of tamping blows is in the range 9–11, and the effective coal gangue improving depth is in the range 6–8m, when the tamping energy is greater than 3000 kN.m. The gradation improved, and the weight percentage of the particles smaller than 4.75 mm was larger than 50%, resulting in better physical and mechanical behavior of the coal gangue filling. The coal gangue filling bearing capacity and anti-deformation ability increase with increasing tamping energy. The coal gangue filling bearing capacity reached at least 350 kPa after being improved by dynamic compaction with a tamping energy greater than 3000kN.m.

Comprehensive Measurement of the Deformation and Failure of Floor Rocks: A Case Study of the Xinglongzhuang Coal Mine

The isolated island panel 10304 of the Xinglongzhuang coal mine was used as the research subject to study the deformation and damage characteristics of the coal seam floor. The damage of the floor was studied using the borehole strain sensing method and borehole imaging technology, and FLAC3D was used to study the influence of abutment pressure on floor failure. The result shows that the floor under the superimposed area which is affected by lateral and advanced abutment pressure is damaged firstly, and the maximum depth reaches 26 m, other areas of the working face about 23 m. The degree of deformation and failure of floor rock at different depths is decreased. The deformation damage increases with the advancement of the working face until a certain distance at the same depth. The hole image can clearly show the influence range of the abutment pressure in front of the coal wall and influence the degree of the advancement and lag by means of the strain increment curve for each sensor probe and the images from different drilled positions. On the basis that the results of simulation and field measurement are consistent, the results can reflect the three-dimensional failure characteristics of the whole island working face floor in the process of coal mining more comprehensively and accurately; moreover, they also can provide important information for mine flood prevention and ecological environment protection.

An approach for water-inrush risk assessment of deep coal seam mining: a case study in Xinlongzhuang coal mine.

Most coal mines in China are opting for deep mining due to the rapid reduction of shallow coal reserves, which increases the risk of water-inrush accidents. Given the limitation of water-inrush coefficient method in evaluating the risk of water inrush from the coal seam floor, we analyzed the permeability resistance of the floor under different lithology combinations, and structural conditions of the lower group coal in Yanzhou mining area, based on the in situ pressure permeability test data. Our comprehensive analysis of the influencing factors of water inrush from the coal seam floor reveals key indices for evaluating the water inrush from the coal seam floor and also recommend values for average water-resistance strength of the different lithology, and structure of the lower coal seam floor of Xinglongzhuang coal mine. Besides, we establish a model based on the water-resistance conditions, and two adjacent lower coal working faces minefields of Xinglongzhuang coal mine in Yanzhou are used for the evaluation. Comparative analysis of water-inrush coefficient method and impermeability resistance condition to evaluate the applicability of safety conditions of coal mining under pressure are also performed. Our results show that the impermeability strength is a better measurement for the water-resistance capacity of the floor. These findings may guide the prevention and control of water disasters in coal mining under pressure in the lower formation of the minefield.

Coordinated exploitation of both coal and deep groundwater resources

Throughout China, both coal and water are very important resources; however, serious conflict can arise between mining of deep coal reserves and essential aquifer resources. The problem is particularly severe in eastern China where a deep, thick, and productive Ordovician limestone aquifer immediately underlies Permo-Carboniferous coal-bearing sediments and poses a serious threat to the safety of coal exploitation. The problems are caused by high water pressures in the Ordovician aquifer and the risk of catastrophic flooding at the coalface caused by strong upward flow across a relatively thin aquitard. The problem can be alleviated by mine dewatering, but this generates large volumes of contaminated wastewater that require safe disposal. In a feasibility study carried out at Yanzhou coalfield, eastern China, hydrogeological studies have been undertaken to explore options for utilizing water pumped during mining operations, thus making more efficient use of the Ordovician groundwater reserves. The groundwaters are recharged at outcrops but readily become SO4·Cl–Ca·Mg in character with TDS increasing considerably with depth. Focusing on the Xinglongzhuang coal mine, test pumping and development of a transient groundwater flow model of the system have allowed alternative strategies for pressure management to be investigated. The study shows that coal-mining operations can proceed safely with as few as six underground dewatering boreholes removing 1800 m3/h. Moreover, the extracted water could be utilized after treatment to reduce sulfate concentrations. The coordinated exploitation approach demonstrated in this study provides a good example of wise environmental stewardship that other extractive industries would do well to consider.

Beneficial Use of Deep Ordovician Limestone Water from Mine Safety Dewatering at the Xinglongzhuang Coal Mine, North China

The use of water from mine dewatering has become increasingly important issue in northern China. Much of this water is discharged to the environment, which wastes a valuable resource and pollutes the ecosystem. To help address this, a feasibility analysis was carried on using deep Ordovician limestone water from dewatering at the Xinglongzhuang coal mine. First, a safe hydraulic pressure was estimated using the conventional water inrush coefficient method. Then, based on the results of a water release test (drilled into an artesian aquifer), a model representing the geology and hydrology of the study area was subsequently established and calibrated to existing conditions and water release test results, using the numerical simulation program FEFLOW. Finally, according to a contract signed between the mine and a local industrial water consumer, two cases of dewatering were discussed using the model to maintain a balance between mining safety and supplying water for nearby industrial operations. During the calibration and prediction analysis, the permeable faults were identified as the most important factor in water management and a key factor for balancing the aforementioned needs.

A new theoretical method for calculating front abutment stress during coal mining

AbstractThe calculation of abutment stress has always been the most important topic in safe underground mining and design. In this paper, based on the formation mechanism of abutment stress, combined with the mechanical properties of actual strata and the theory of elastic foundation beams, a structure model of overlying strata with an elastic foundation is established, and a new theoretical calculation method of abutment stress is proposed. The new calculation method takes into account the interaction of the overlying key strata and the effect on the transmission of the front abutment stress and then analyzes the stress patterns of multilayered key strata under the combined action of the bending moment, shear force, and nonuniform load and its transmission to the underlying strata. In addition, based on field observations of panel 10 305 in the Xinglongzhuang coalmine, the influence range, peak position, and variation trend of the front abutment stress before and after breaking of the overlying key strata are studied and verified. The results show that the influence range of the abutment stress remains unchanged after KS1 breaks (eg, from 0 to 180 m), and its peak position shifts forward from 8 to 19 m, while the influence range (0‐180 m) and its peak position (6‐8 m in front of coal wall) remain unchanged after KS2 breaks; the abutment stress decreases, and the maximum decrease is 3.9 MPa in the range of 0‐22 m ahead of the coal wall after KS1 breaks, while the maximum decrease in the abutment stress is 2.1 MPa in the range of 0‐71 m ahead of the coal wall after KS2 breaks. The results of the new calculation method are basically consistent with the field observations and the existing theoretical results, showing that the method has good adaptability and reliability and can provide a new theoretical basis for on‐site design and construction practices.

Research on Mine Ventilation Optimization Based on 3D Simulation System

Based on the application of Ventsim software as the analysis tool and the modern optimization design method as the theoretical basis, aiming at the current situation of the ventilation reversal, large ventilation resistance and insufficient safety equipment investment in the mine of Xinglongzhuang Coal Mine, combined with the basic data of the mine, the mine ventilation three-dimensional is established. The simulation model is used to construct a three-dimensional simulation system for mine ventilation. The mine ventilation three-dimensional simulation system is used to simulate the solutions of ventilation reversal and mine ventilation, so as to realize the optimal design of the ventilation system, effectively ensure the ventilation needs of the normal production of Xinglongzhuang Coal Mine, and improve the visualization of the regulation of the mine ventilation system. automation.

Effects of coal mining on the evolution of groundwater hydrogeochemistry

The mining industry, especially coal mining, may severely affect the spatial and temporal evolution of groundwater. To provide a potential model outlining the hydrogeochemical evolution of groundwater as influenced by coal mining, a multi-layer groundwater system in a coal mining area was investigated. A total of 76 groundwater samples were collected between 1964 and 2018 for hydrogeochemical analysis from boreholes, underground tunnels, and surface pits at Xinglongzhuang Coal Mine in China. Hierarchical cluster analysis and principal component analysis were used to classify four significant groundwater zones and two principal components. The results showed that mining may have caused the rock strata to sink, obstructing the path linking the Permian and lower Quaternary aquifers, and resulting in intensified ion exchange in the lower Quaternary aquifer. The concentrations of Na+ and Ca2+ in the groundwater from the lower Quaternary aquifer changed over the studied period (~54 years). The gradual increase of Na+ and decrease of Ca2+ concentration verified the action of cation exchange. The four main aquifers had relatively independent hydrogeochemistry, suggesting that the hydraulic conductivity of the natural faults is weak and the sealing properties of hydrogeological drill holes in the coal field are good. Analysis of 26 heavy metals in the mine drainage water showed that there is only minor pollution after the water has been simply treated. These data analysis methods and results could be useful in areas with long-term mining to interpret the evolution of groundwater and to promote groundwater quality management.

Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

Development of Mine Water Source Identification System Based on MapObjects

In order to realize the mine water source identification and to prevent water accidents, taking Xinglong Zhuang coal mine’s lower group coal mining as an example, based on the analysis of mine hydrogeological conditions, the mine water source identification system was designed by using the software of MapObjects powerful spatial analysis ability and Bayesian classification analytical method. The software can achieve mine water source identification and provide a certain basis for mine water disaster prevention and control.

The Dynamic Monitoring on Mining Collapsing around Xinglongzhuang Coal Mine Based on Remote Sensing Images

A large number of old coal mine, such as Xinglongzhuang coal mine, made a great contribution to local economic development and national construction. But, serious mining collapsing was caused also, and local people's livelihood has been affected seriously. The mining collapsing could be identified on remote sensing images by some characteristics. There were 4 period remote sensing data, which was acquired respectively in June 2009, April 2010, June 2011 and July 2012, and field investigation were applied in this articles to study these mining collapsing. The research suggests that the mining collapsing could be divided into the aged type, the middle aged type and the young type. There is a suggestion that, the monitoring and prevention works should be strengthened.

Restriction function of lithology and its composite structure to deformation and failure of mining coal seam floor

In order to research the relationship between deformation and failure depth and lithology and its composite structure, in situ test data on the deformation and structure variation of rocks in different depth of the coal seam floor were utilized on Xinglongzhuang Coal Mine and Baodian Coal Mine in Yanzhou Mining Area by strain testing system and ultrasonic imaging technology in the fully mechanized top-coal working face, and the data on the East Main Haulage of −300 m lever in Peigou Coal Mine in Zhengzhou Mining Area in China were also used. There are obviously different deformation and failure characteristics of similarly homogeneous floor and soft–hard composite structure rocks floor under the mining pressure, which are based on the in situ test data. The research shows that the law of deformation and failure of similarly homogeneous floor is relatively simple; the deformation and failure depth are restricted by the strength of floor rock and has a gradual variation from top to bottom. But the deformation and failure of the interbedded soft–hard rock mining floor are more complex; this kind of structure has a obviously restricting function on the failure depth and deformation degree of the mining floor, and the weak intercalation has a strong constraint effect to the depth of floor failure which implies that the soft rocks have a “cushion effect” on the overlying hard rocks and a “stress diffusion effect” on the underlying hard rocks.

Grout diffusion characteristics during chemical grouting in a deep water-bearing sand layer

The deep, loose bottom aquifer of the eastern air shaft in the Xinglongzhuang Coal Mine was used to develop an experimental model of shaft grouting through Model deep soil. Lab experiments using chemical grouting were done to study the grout. The grouted soil shapes and osmotic pressure were measured during the experiments. The tested characteristics of the grouted soil show that the diffusion mode of grout in saturated sandy soil is a combination of split compaction and osmosis. More specifically, the shape of the grouted soil is determined by split compaction while the size of the grouted soil shape is determined by osmosis. Sensor test results indicate that the main reason for the non-uniform grout diffusion is the anisotropic osmotic pressure field surrounding the grouting holes.

Distribution and mode of occurrence of As, Hg and Se and Sulfur in coal Seam 3 of the Shanxi Formation,Yanzhou Coalfield, China

Abstract The Yanzhou mining area in the west Shandong Province, China contains coals of Permian and Carboniferous age. A total of 21 bench coal samples were collected from coal seam 3 of the Permian Shanxi Formation, Xinglongzhuang coal mine, Yanzhou Coalfield, China. Pyritic and organic sulfur generally account for the bulk of the sulfur in coal. In this paper, the distribution and concentration of sulfur in the Yanzhou mining district are analyzed, and the forms of sulfur are studied. Organic sulfur content was determined by substraction and it is positively correlated to total and pyritic sulfur. The vertical variation of Hg, As and Se and sulfur contents in coal seam 3 of the Shanxi Formation in the Xinglongzhuang mine show that all these trace elements are enriched in the roof and floor rocks of the coal bed and that the concentrations are also relatively high in the clay partings within the coal bed. In the studied samples, Hg and Se have an even higher concentration than that in the world coals. The concentrations of Hg and Se in the seam studied are greater than the global mean of these elements in coals. Se content in the studied coal is 5 times as high as the world coal value and Hg is about one to two orders of magnitude above World Clarke value. Hg is also more enriched compared to the average concentration in Chinese coals. The pyritic sulfur is positively correlated with total sulfur, and both are enriched in the roof rock, floor rock and clay parting of the coal bed. The concentrations of the trace elements As, Hg and Se are closely related to sulfur. Hg correlates more with pyritic sulfur than organic sulfur. Se relates more to organic sulfur than to pyritic sulfur. As is almost equally related to organic sulfur and pyritic sulfur. Therefore three trace elements may be mainly associated with sulfides and other inorganic matter, also occur in organic forms, especially for Se, already sard this.