Mine Water Disaster Research Articles

A Case Study of the Water Abundance Evaluation of Roof Aquifer Based on the Development Height of Water-Conducting Fracture Zone

In the eastern mining area of Ningxia, China, multi-layered sandstone aquifers are widely distributed in the underground. However, the water abundance of these aquifers is not clear, which brings great challenges to the prevention and control of mine water disaster. In this paper, five mining areas in eastern Ningxia were taken as the study area, and the distribution characteristics of aquifer and the mine water filling source were analyzed through the analysis of geological data and numerical simulation. Finally, the lithology influencing index (LII) was constructed, and the water abundance of the aquifer was evaluated. The results show that the sandstone aquifer III in the lower part of the Jurassic Zhiluo formation is the main water-source aquifer of the #2 coal seam in the study area, while the middle aquifer II and the upper aquifer I are indirect water-source aquifers; the areas with extremely strong and strong water abundance are Maiduoshan, Hongliu, the south of Shicaocun, southeast and southwest of Meihuajing, and the central and southern areas of Shuangma mining areas; when the depth of water drainage boreholes in the roof reaches the development height of the water-conducting fracture zone, the pre-drainage measures can effectively control the mining inrush water of the working face and ensure the safety production. This research is of great significance to the prevention and control of mine water disaster.

A case study of floor failure characteristics under fully mechanised caving mining conditions in extra-thick coal seams

AbstractTo determine the failure characteristics and evolution regularity of the floor strata during fully mechanised top-coal cave mining in typical deep and extra-thick seams in western China, the 61303 working face of an Ordos mine was selected as the engineering research object. A comprehensive monitoring method combining a BOTDR (Brillouin Optical Time-Domain Reflection) distributed fiber strain test and a borehole resistivity CT (Computerised Tomography) test was adopted. The results show that floor stress distribution of the deep-buried and extra-thick coal seam is significantly affected by the different depths of rock lithology. At the interface of the rock strata with a large difference in the elastic modulus, phenomena such as the asynchronism of strata movement and obvious differences in failure easily occur. The failure depth of the floor strata in the 61303 working face is approximately 15.90 m, and the influence depth of the floor disturbance is approximately 32.70 m. Under the influence of the mining pressure, floor stress distribution and crack evolution have obvious spatial and temporal effects. In different inclined boreholes, the data captured by the cable have different values and the fracture locations of the cable also differ. Compared with a single borehole, multiple boreholes with different inclinations, directions and locations can provide more comprehensive and reliable data trends. The knowledge obtained by this monitoring can provide reference information for the study of floor damage under similar conditions and the formulation of technical measures such as those that prevent mine water disasters.

Evaluation of roadway water hazard level based on extension connetion cloud model

Accurately assessment of water hazard level in coal mine can improve the water hazard prevention and control in coal mine and reduce the occurrence of water inrush disaster. Based on the theoretical and practical study of coal mine water disaster accidents, a water disaster assessment index system was established. The transformation between qualitative and quantitative indicators was realized by the matter-element extension theory and the cloud model, the state value of the index and the corresponding risk grade membership value were determined by the connection cloud model, and the method of game theory was used to value the comprehensive weight of evaluation index to reduce the randomness and subjectivity in the determination of weight. Based on the principle of distance similarity, the evolution trend of risk can was estimated to strengthen the early warning of trend risk. The application in Feicheng mining area showed that the extension connection cloud model evaluation is appropriate to the evaluation of coal mine water hazard, and the quantitative characterization of water hazard risk is of great significance to guide coal production to be safe.

The design of coal mine water disasters prevention and control assistance decision system

According to actual situation of coal mine water disasters and the expert system research survey, the author has proposed the overall structure of the assistance decision system. The author has established the coal mine water disasters assistance decision platform based on dot NET soft. We has realized the formulation of determination and the preventing and controlling measure of the flood of old hole, roof, floor by using dot Net soft and the CLIPS computer language, combining with database platform established the expert knowledge library and the inference library; has solved the time and the spatial disposition question of the most superior sparse water volume by using the methods of finite element and the linear programming; Moreover aims at these questions of the note thick liquid, searching and draining water, the setup of waterproof rock seam, the forecast of water inflow volume, we has produced the correlation computational methods result and the operation craft.

Science mapping approach to assisting the review of mine water disaster prediction and evaluation in China between 2009 and 2019

Mine water inrush occurs frequently in China, and it can cause serious economic losses and heavy casualties. Thus, it is very important to realize risk assessment of mine water inrush. After collecting 4082 journal documents on risk assessment of mine water inrush from 2009 to 2019 in CNKI journal database, and using CiteSpace visualization software to do data analysis, the research hotspot and frontier trend in mine water inrush research in China are obtai ned. The prevention and prediction of different types of water disasters is a major trend in this field.

Hydrogeochemical Characteristics and Groundwater Inrush Source Identification for a Multi‐aquifer System in a Coal Mine

Correct identification of water inrush sources is particularly important to prevent and control mine water disasters. Hydrochemical analysis, Fisher discriminant analysis, and geothermal verification analysis were used to identify and verify the water sources of the multi‐aquifer groundwater system in Gubei coal mine, Anhui Province, North China. Results show that hydrochemical water types of the Cenozoic top aquifer included HCO3–Na+K–Ca, HCO3–Na+K–Mg and HCO3–Na+K, and this aquifer was easily distinguishable from other aquifers because of its low concentration of Na++K+ and Cl–. The Cenozoic middle and bottom aquifers, the Permian fissure aquifer, and the Taiyuan and Ordovician limestone aquifers were mainly characterized by the Cl–Na+K and SO4–Cl‐Na+K or HCO3–Cl–Na+K water types, and their hydrogeochemistries were similar. Therefore, water sources could not be identified via hydrochemical analysis. Fisher model was established based on the hydrogeochemical characteristics, and its discrimination rate was 89.19%. Fisher discrimination results were improved by combining them with the geothermal analysis results, and this combination increased the identification rate to 97.3 % and reasonably explained the reasons behind two water samples misjudgments. The methods described herein are also applicable to other mines with similar geological and hydrogeological conditions in North China.

The multiple logistic regression recognition model for mine water inrush source based on cluster analysis

Mine water inrush is one of the major geological hazards that threaten safe production in coal mines. The accurate identification of mine water inrush sources plays a vital role in mine water disaster control, and it is the key to preventing mine water inrush incidents. Ninety-three water samples were extracted from the three types of aquifers in the Qinan coal mine. The cluster analysis method was then used to analyze 82 of the original water samples, and the other 11 water samples that did not meet the requirements were removed. Then, the remaining 82 water samples were regarded as training samples, and the principal component analysis was completed. Taking the scores of the principal components as the independent variable and the types of water inrush sources as the dependent variable, the multiple logistic regression recognition model was established. Meanwhile, this recognition model was used to recognize the types of mine water inrush sources and verify the recognition accuracy for the 82 training samples. The comprehensive recognition accuracy reached 86.6%, which is much higher than the traditional recognition methods of water inrush sources. Based on cluster analysis, the multiple logistic regression recognition model fully considers the ion content measurement errors and the complex relationships between the internal ions, and this recognition model is more reasonable and improves the accuracy of water inrush source recognition. This paper provides a new method for recognizing the problem of water inrush sources, which also provides an effective basis for mine water inrush prevention and control.

The Overburden Strata Caving Characteristics and Height Determination of Water Conducting Fracture Zone in Fully Mechanized Caving Mining of Extra Thick Coal Seam

The deformation, fracture and movement of the stope roof in fully mechanized top-coal caving mining in extra-thick seam are very serious, once there are aquifers, the formation of water diversion channel may lead to mine water disasters. Aiming at this issues, the characteristics of overburden caving and the height of water-conducting fracture zone in fully mechanized top-coal caving mining in extra-thick seam was researched, based on the engineering geological conditions of a mine in Shendong, the height of coal caving zone and water-conducting fracture zone in the lower group of close seam was theoretically analyzed, and the height of “two zones” was estimated. Similar simulation and numerical simulation experiments were applied to analyze the caving characteristics of overburden in fully mechanized top-coal caving panel of extra-thick seam. Results showing that after the full settlement and compaction of the roof after the mining of upper layer, the fractured zone of water conduction in the mining of medium layer could not reach the loose porous aquifer, in order to reduce the threat of the underground water body, the stratum should be fully subsided and compacted before the mining of lower layer.

Research progress, problems and prospects of mine water treatment technology and resource utilization in China

The National Development and Reform Commission and the Energy Bureau jointly issued the ‘Plant Water Utilization Development Plan’ on January 29, 2013, which requires that China should gradually establish a more complete legal system, macro management and technical support system for mine water in 2015. But so far, due to the influence of geological conditions and other factors, the impurity composition and content of mine water is very different. Based on the comprehensive summary of the theory, method, application technology, practical engineering and processing technology of mine water disaster and its reutilization in China. This article systematically analyzed the latest research progress and achievements, which include basic theory, hydrogeology (supplement) exploration, advanced detection and monitoring as well as early warning. These can further promote application of current technology, develop new technology and methods, point out the challenges and the existing problems of the mine water field, the gaps with requirements of fast, intensive, and large-scale development of the coal industry in China. Finally, the development trends, future important scientific innovation and key technology were discussed. The prospects of the industry and technology were also forecast.

Formation mechanism and prediction method of water inrush from separated layers within coal seam mining: A case study in the Shilawusu mining area, China

Water inrush form separated layers (WIFSL) is one type of mine water disaster, threatening the safety of coal mines. A thorough understanding of WIFSL formation mechanisms is prerequisite for creating water control measures. In this study, the formation conditions of roof bedding separation, menacing bed separation water and formation conditions of WIFSL were examined. According to the composite beam theory, the traditional criterion for bed separation location is revised. Combining the Winkler foundation beam model, the mechanical model for bed-separation water hazard above the water-flowing fractured zone (WFFZ) was established, and the theoretical discriminant of the first and periodic WIFSL was deduced. In addition, the water inrush coefficient method was used to divide the WIFSL risk. The results of this study show that separation locations are controlled by a combination of lithology, rock thickness, and elastic modulus. The formation of bed separation water is restricted by the separation locations and recharge water source. The formation of WIFSL mainly depends on the strength and thickness of the protective layer, between the bed separation and the WFFZ, and the foundation coefficient of the fractured rock mass in the WFFZ. Taking Shilawusu coal mine, Dongsheng coalfield, Inner Mongolia autonomous region, China as the application examples, the risk of WIFSL within the mining area was predicted and classified. In addition, theoretical analysis and calculation of bed separation locations, foundation coefficient, and periodic inrush distance of WIFSL within the 06A working face were carried out, verifying the accuracy of the theoretical model and prediction method in this study.

Experimental Study on Seepage Characteristics of Fractured Rock Mass and Its Electrical Response

AbstractFissure seepage is the main factor that causes mine water disasters. Physical models of the fractured rock mass with various widths of fracture were designed to perform the seepage test, wh...

The identification of fault zones in deep karst aquifer of North China coal mine using parallel directional well logs

Water inrush from Ordovician karst aquifer in North China coal mine has become a key issue on underground coal mining. To address this problem, it is necessary to identify fault zones, because fault zones might connect limestone aquifers and coal seams, enabling Ordovician karst water to enter the mine. In the study area, a series of parallel directional holes were drilled along Ordovician limestone at depths between 70 and 90 m under Ordovician limestone boundary. To conveniently detect fault zones and govern mine water disasters, a series of natural gamma-ray logging while drilling (GRLWD) were undertaken. The entire detecting region can be comprehensively covered by several directional borehole groups. Then, fast Fourier transform and short-time Fourier transform approaches were employed on the basis of GRLWD data and geological data to extract faults information. A segmented identification method for deep fault zones was established in this study. This method can be used to markedly improve the identification of fault zones within Ordovician limestone or the unitary lithology formation and provide crucial information relevant for deep coal mining safety.

Geological characteristics of the main aquifer coal seam in the Ordos Basin coalfield, China

The main aquifer coal seam within the Ordos Basin (OB) coalfield, China, is an extremely rare example of a hydrogeological feature that is found relatively recently during basin development. Mine water gushed from this coal seam during the construction and production phases of the coalfield. However, because this seam has traditionally been considered as an aquifuge, the special geological conditions it creates have led to a range of new challenges in mine water disaster prevention, control, and management as characteristics of both confined and unconfined aquifers are evident. The aim of this paper is to reveal the causes underlying the formation of this main aquifer coal seam by analyzing hydrodynamic conditions, hydrogeological structures, and the surrounding lithological association. In addition, the particular geological conditions created by the presence of this feature are discussed, with emphasis on their influences on mine construction and production. This study provides an important theoretical basis for the future study of mine water disaster prevention as well as a potential method for disaster control that can be applied in the case of particular hydrogeological conditions.

Groundwater Source Discrimination and Proportion Determination of Mine Inflow Using Ion Analyses: A Case Study from the Longmen Coal Mine, Henan Province, China

Complex hydrogeological conditions in China’s coal mines have contributed to frequent mine water disasters. A simple and effective method to determine water inflow sources and paths is therefore essential. The Longmen Mine, located in Henan Province, in central China was used as a case study. A Piper diagram and cluster analysis were used to screen the characteristic values of 18 water samples from potential aquifers. A comprehensive fuzzy evaluation of the groundwater ions was carried out to determine the main source of the total mine inflow. Then, based on conservation of ionic masses, a matrix function was established to calculate the groundwater recharge composition. Finally, using measured water inflows for the Cambrian limestone aquifer, the calculated and observed results were compared. The results showed that the Carboniferous Taiyuan Formation limestone aquifer (the L7 limestone aquifer) accounts for 60.8% of the total mine inflow, while the Cambrian limestone and roof sandstone aquifers account for 34.8 and 4.4% of the inflow, respectively. The normal mine inflow totals about 19,200 m3/day, of which 6,840 m3/day is from the Cambrian limestone aquifer. This agrees well with the calculated value of 6,720 m3/day. Thus, the method is feasible and reliable.

Influential factors and control of water inrush in a coal seam as the main aquifer

In this paper, a combination of field measurement, theoretical analysis and numerical simulation were used to study the main control factors of coal mine water inrush in a main aquifer coal seam and its control scheme. On the basis of revealing and analyzing the coal seam as the main aquifer in western coal mine of Xiao Jihan coal mine, the simulation software of PHASE-2D was applied to analyze the water inflow under different influencing factors. The results showed that water inflow increases logarithmically with the coal seam thickness, increases as a power function with the permeability coefficient of the coal seam, and increases linearly with the coal seam burial depth and the head pressure; The evaluation model for the factors of coal seam water inrush was gained by using nonlinear regression analysis with SPSS. The mine water inrush risk evaluation partition within the scope of the mining field was obtained, through the engineering application in Xiao Jihan coal mine. To ensure the safe and efficient production of the mine, we studied the coal mine water disaster prevention and control measures of a main aquifer coal seam in aspects of roadway driving and coal seam mining.

A Review of Geophysical Exploration Technology for Mine Water Disaster in China: Applications and Trends

Geophysical exploration can be effective in detecting and monitoring potential sources of coal mine water in-rushes and underground watercourses. Generally, in-mine seismic, DC resistivity, and transient electromagnetic methods are used for such purposes in China. However, such technologies can be influenced by many factors, such as roadways, fissures in the surrounding rocks, and various secondary conditions. Our review of current geophysical methods and tools concludes that further basic research should be carried out on geophysical field propagation in the whole space, data collection methods, and inversion methods appropriate for the special environment of coal mines. Moreover, borehole and roadway space should be designed to incorporate effective geophysical drilling, cross-hole exploration, drilling–roadway exploration, and roadway–roadway exploration. Future hydrogeophysical exploration research should focus on comprehensive geophysical methods combining multi-field synergistic observations with multi-field data integration and automatic monitoring as well as early warning systems for mine water disasters combining real-time processing and analysis of exploration equipment with Internet of Things technology.

我国矿井水文地质工作面临的挑战与展望

以《煤矿防治水规定》为准则，以水文地质理论为指导，从矿井高效安全生产、经济实用的角度出发，通过分析现阶段我国矿井水文地质工作的现状，指出我国矿井水文地质工作面临的六大挑战，并且提出切实可行的展望。分析认为，只有通过建立以技术和管理为核心的综合性水文地质工作体系，充分利用和发挥现有的技术以及设备，并且不断的探索进取，寻求更加优化的矿井水文地质工作技术、体系，才能从根本上解决矿井水害以及矿井排供水等问题。 Based on the Provisions for Mine Water Prevention and Control, guided by the hydrogeology theory, from the perspective of efficient, safe, economic and practical coal mine production, this paper analyzed the present situation of mine hydrogeological work in China, pointed out the six challenges facing mine hydrogeological work in China and put forward the feasible countermeasure and prospect. The analysis suggests that only by establishing the integrated hydrological geological work system based on the technology and management, making full use of the existing technology and equipment, and continuously exploring and seeking more optimization system and technology of mine hydrogeology work, can the problem of mine water disasters and mine drainage water be fundamentally solved.

Quantitative Prediction of Water Volumes Within a Coal Mine Underlying Limestone Strata Using Geophysical Methods

Mine water and mine inflow water are closely linked to the risk of mine water disasters. The relationships between various geophysical parameters and the volume of water in mine tunnels were considered by using an integrated suite of appropriate geophysical methods [i.e. direct current (DC) resistivity, transient electromagnetic method (TEM), and the seismic scattered wave method], and knowledge of the essential features of seam floor water in karst coal mine settings. By constructing a 3-dimensional physical simulation of water-bearing limestone, a quantitative predictive formula for water volume in abnormal bodies was derived in terms of the parameters of the selected suite of geophysical methods. Water volume was determined by using apparent resistivity (obtained from the DC resistivity survey and TEM), a measure of the amount of potentially water-containing space, and a correction coefficient. The quantitative formula was adjusted for accuracy using field data, and then tested at a specific field site. The average accuracy of predictions using the composite quantitative formula was 75.8 %, which is considered to be high. The formula presented in this paper could contribute significantly to the prevention and mitigation of water-related disasters in karst coal mines.

Study on Failure Characteristic Simulation of Seam Floor for Coal Mining above Confined Aquifer Based on Fluid-Solid Coupling Theory

Water inrush is one of the main types of coal mine water disaster. Based on fluid-solid coupling theory, the confined water inrush numerical model is performed using FLAC3D program and similar simulation experiment, and the floor damage field and confined water vector field are simulated. The results show that, in the coupling action of mining stress and pressure of confined water, the mining floor was divided into four zones, namely the mining damage zone, effective confining protection zone, confined water soil-fluid coupling lifting zone, original confined water lifting zone. Confined water-conductive zone with the periodic roof pressure fluctuate, at each pressure and flowing zone height reaches the maximum, rise with height remained unchanged, the distribution shape of a "wave", water inrush is the results of effective connectivity of mining damage zone and Confined water-conductive zone, plate thickness of water-resisting layer exists or not, waterproof performance and the pressure of confined water inrush size is the key

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.