Search

In China,many mining areas with extremely thick and hard rock strata has strong mine earthquake and strong rock burst caused by the movement of extremely thick and hard rock strata which have serious consequences,is difficult to be controlled and has become the main obstacle to mine safe production.Based on the analysis of the occurrence law of rock burst under extremely thick and hard rock strata, the paper puts forward three common characteristics of rock burst in such mines: "the effect of key working face", "the effect of vibration-induced rock burst"and "the effect of rock burst and vibration. ""Key working face "means that the mining of this working face will lead to the fracture and strong movement of extremely thick and hard rock strata and the occurrence of strong earthquake or rock burst. "The effect of key working face"refers to the strong dynamic disasters occurring in the mining process of "key working face". "The effect of vibration-induced rock burst"refers to the rock-burst hazards caused by the dynamic stress which generated by the fracture and vibration of extremely thick and hard rock strata propagating to the coal body in the high stress state. Its feature is that "the location of the source is different from that of rock burst. ""The effect of rock burst and vibration"means that when the key working face is mined, the transmission pressure of extremely thick and hard rock strata will increase sharply.When part of the coal reaches the condition of rock burst, the rock burst will occur and cause vibrations with great energy. The characteristic of this kind of rock burst is that" the location of the source is the same as that of rock burst. "Using the theory of overlying strata spatial structure, surface subsidence observation and monitoring data of microseism and stress, a method for identifying the key working face is proposed. This paper describes the concrete methods of preventing rock burst and ensuring safety in three different types of mines with extremely thick and hard strata and the possibility of rock-burst disasters in Shandong Energy Group. These methods include protection layer mining, negative coal pillar design,determination and parameter design of key working face, mining design to avoid the boundary of vibration damage, small coal pillar design and parameter optimization design of sequential mining face. [ABSTRACT FROM AUTHOR]

To study the evolution characteristics of unloading damage and deformation of underlying coal and rock during the protective layer mining period, FLAC3D numerical simulation was conducted based on the actual conditions of Baode Coal Mine in Shanxi Province, China. In-situ investigations were also adopted to verify the simulation results on stress, deformation and plastic property evolution laws. The results show that the stress of the protected layer increases firstly, then decreases and after which increases again during the mining process. The spatial distribution of stress on underlying coal and rock shows an obvious “O” shape. Influenced by the protective layer mining, the measurement points in underlying coal seam experienced four stages including original rock stress, stress concentration, mining pressure relief and stress recovery. The ratio of the maximum stress concentration factor and the minimum unloading stress is a constant value, and the occurrence of the two extreme values shares the same time. The stress concentration factor in front of the working face and the unloading ratio behind the working face all change reciprocally, and the change period is related to the cycle stress from the working face. In this paper, the maximum stress concentration factor is about 1. 32, at which time the value of the z-direction stress at the measuring point is the largest. The minimum pressure relief ratio is about 4. 4% and the z-direction stress value at the measuring point is the smallest at this time and the pressure relief effect is also the best. Under the effects of changing stress, the deformation of the protected layer presents the basic rule of compres-sion-recovery-expansion-retraction cycle. The final state maintains a certain expansion deformation, which corre-sponds to the stress zoning. According to the different deformation characteristics, the underlying coal seam can be divided into original rock state zone, compression deformation zone, pressure relief expansion zone and de-formation recovery zone. The example in this paper shows that the maximum expansion deformation of No. 11 coal seam was 0. 6%. The cracks at the monitoring points developed well and the permeability increased significantly, which was conducive to gas pressure relief and extraction. Under the influence of stress changes, the plastic area increased in triaxial directions first, then increased in x-axis direction but y-axis and z-axis direction kept stable. With the advance of working face, the plastic zone of coal body in protected seam increased continuously in the x-axis direction. By measuring the in-situ stress and expansion deformation of No. 11 coal in the mining process of 81307 working face in Baode Coal Mine, the numerical simulation results of the evolution characteristics of unloading damage and deformation during deep mining were verified. The variation laws of in-situ stress and expansion deformation of No. 11 coal agree well with those of numerical simulation. [ABSTRACT FROM AUTHOR]

The existing mine planning in China is mainly based on the practice of shallow mining, and usually only considers economic and engineering factors. Mining planning is carried out throughout the whole life of the mine, giving priority to high-grade ore for maximum economic benefit. Deep mining is in a complex geomechanical environment caused by three “high” and one “disturbance”, and the influence of high ground stress is an important factor in deep mine planning. This paper has carried out literature review on the overall planning of metal ore in deep high stress environment. Firstly, this paper aims at realizing the investment value of mine resource development, and discusses the process from the whole to the partial design of deep mine from two dimensions of strategic planning and tactical planning, which is suitable for the overall planning of general deep mines. The practical significance of the timeliness of rock strength to the overall planning of deep mines is analyzed. Secondly, the design and layout of deep mines at home and abroad under high stress conditions are expounded. The “V” type and the inverted “V” type mining sequence are applied to the deep mining and failed to balance “improving the stress state” and obtaining the maximum net present value, correspondingly, thus, the ideal surrounding mining sequence is a balanced mining layout. However, the mine layout and the stress state of stope need to be further explored in the actual mining application process. Finally, the importance of stress prediction and calibration in the overall planning model for predicting high-risk areas and guiding deep mine planning is pointed out. In deep mine planning, further research works, for example, fully considering the engineering impact of high stress environment, and how to fully integrate the high stress environment and its evolution law with the mining process, are needed. [ABSTRACT FROM AUTHOR]

Because of bad contact or mechanical damage, the coal power supply system might produce series arc fault. Series arc fault is one of the causes of electrical fire in coal mines. There may be inflammable and explosive materials such as gas and coal dust in the underground. It is not suitable to carry out series arc fault experiment, and thus a lot of fault diagnosis samples cannot be obtained, which brings difficulties for arc fault diagnosis. In order to study the typical characteristics and diagnostic methods of series fault arcs in mine power supply system, a series arc fault simulation model based on the Mayr Schwarz arc mathematical model was established for mine power supply system and the performance of this simulation model was evaluated in this paper. Then it simulated and analyzed the electrical faults such as series arc fault, over voltage, single phase ground, two phase ground short circuit, two phase short circuit, three phase short circuit in the coal mining system, belt conveyor system, pump house drainage system, lighting system of mine power supply system. Also, the series arc fault characteristic parameter database of mine power supply system was established by using Zero crossing point, peak to peak value, variance, kurtosis coefficient, margin factor, harmonic distortion rate, unilateral power spectrum frequency variance, wavelet packet coefficient energy entropy, wavelet packet coefficient peak to peak value as feature variables. Finally, the paper comprehensively compared the performance of decision tree, K nearest neighbor and Bagged trees multi classification pattern recognition method in fault arc diagnosis, phase selection and anti load current fluctuation disturbance, anti background noise disturbance, and proposed series arc fault diagnosis method for K nearest neighbor mine power supply system. The results show that the established series arc fault simulation model can be used to simulate and analyze the series arc fault of mine power supply system and the database established in this paper can reflect the typical characteristics of series arc fault in mine power supply system. It also showed that K nearest series arc fault diagnosis method can be used for the series arc fault diagnosis and phase selection of mine power supply system. [ABSTRACT FROM AUTHOR]

Coal mining involves extracting the resources from the earth. It will disturb the strata in the mining area, which inevitably causes strata movement and the change of stress and fracture fields, thus affect safety and environmental such as the occurrence of ground pressure, groundwater loss and surface subsidence. Therefore, mining-induced strata movement and its influence on safety and environment are the basic scientific problems of coal mining. The understanding of these laws will improve the scientific nature of coal mining. Because of the complexity of strata movement, however, there are still several issues to be addressed. This paper introduces the mining-induced strata movement of the block structure, which is followed by the review of advances and outstanding issues in the influence of strata movement on longwall face support, mining-induced fractures evolution, groundwater, surface subsidence, and mininginduced stress field. It is found that mining-induced strata movement is a combination of stress concentration caused by the span of thick and hard strata and the mechanical behaviors of the rock blocks associated with the breakage of the strata. During the collapse of thick strata and the corresponding rock block movement, the characteristics of mutations and discontinuities typically occur. In such a process, a structure that can sustain large deformation may be formed after the rock blocks are hinged. The “R.-S” stability of the structure causes significant influence to such phenomena as the occurrence of ground pressure, mining-induced fractures and surface subsidence. Mining-induced strata movement is like a “black box” system. Currently it is just explained in the aspect of control principle, and reaches the level of a “gray box” system. Therefore, strata control refers to “macroscopic” control in many engineering cases. The Voussoir Beam model has established longwall support theory and the estimation principle of support working resistance. In a general case, the support resistance that is determined as the weight of the overburden with a thickness of 4 -8 times the mining height could meet the safety requirements of most mining projects. Specially,8 times should be chosen for the longwalls with a large mining height or a thin immediate roof, a shallow cover depth,or the support crush risks. As for some particular conditions, however, support crush cannot be avoided by the single measure of increasing support resistance, but should be combined with other engineering precautionary measures. According to the stability of rock blocks of overburden key strata, three types were proposed to characterize surface subsidence for varied alluvium conditions in different areas of China. It is suggested that subsidence type should be considered during the selection of subsidence prediction, control and reclamation methods. The presence of key strata and the corresponding breakage characteristics play a vital role in the distribution of mining-induced stress. At present, the prevention of accidents caused by stress concentration is harder than that of methane accidents. With this in mind, it is suggested that only test-style mines could be established in the areas with tectonic stress concentration or a large depth. This paper points out the direction for the study of strata movement and the corresponding influence on safety and environment in the coal mining industry. [ABSTRACT FROM AUTHOR]

The stress state of a point in the material can be indicated by a Mohr circle and the different stress states of a point can be determined by charging stress circle under the coordinate system. The transformation of stress circle can be mainly divided into translation, flipping, radius expand and radius diminution. For rock material, these transformations almost include all the processes of loading and unloading. Loading and unloading rate can be used to indicate the speed of transformation between different stress states, and it is not only the change of unit time, but also the change of unit space scale,such as unit length, unit depth, etc. Based on the Mohr-Coulomb criterion, this paper analyzed the rock materials loading and unloading processes under the states of compression-compression, tension-tension and tension- compression, and found out the corresponding critical failure equation. On this basis, the relationship between time-weighted average loading and unloading rate of rock materials and the destruction level of rock materials were further obtained. According to the different time-weighted average loading and unloading rates, this paper also distinguished whether the rock materials is destroyed. This research adopted the FLAC30 conventional three-axis numerical simulation experiments of seven different loading paths. The result showed when the material is damaged, the coincidence degree of the principle stress peak and the theoretical calculation result is as high as 98%. At the same time, this paper also conducted some simulation experiments under the conditions of seven kinds of axial and radial loading rates ratio and four types of loading rates. The test results indicated that the material is able to be destroyed when the ratio of the axial and radial loading rates reach within a certain range. The loading rate is positively correlated with the maximum principal stress peak,which occurs at the state of material failure, and negatively correlated with the ratio of the maximum to the minimum principal stress. [ABSTRACT FROM AUTHOR]

The accurate measurement of rock cohesion c and internal friction angle φ( hereinafter referred to as the c-φ parameter) is the basis of optimizing the design of underground engineering support and information construction. The traditional indoor test method has the characteristics of cumbersome testing steps, long cycle and high cost, and cannot carry out in-situ measurement. Therefore, it is necessary to develop an accurate and fast on-site testing method for rock c-φ. Digital drilling testing technology provides a new way for accurate and fast prediction of rock c-φ in-situ, and the key is to establish the quantitative relationship between drilling parameters and rock c-φ. According to the fracture characteristics of rock cutting, a rock cutting mechanics model without prior assumption of failure surface is proposed. This model makes up for the deficiency of the existing rock cutting mechanics model that assumes the failure surface as a plane and thus differs from the actual characteristics of the failure surface in rock cutting. The ultimate cutting force is deduced on the basis of the slip-line theory. Based on this, the relationship between drilling parameters( DP) and c-φ parameter( hereinafter referred to as the DP-cφ relationship) is established. In this paper, the digital drilling test is carried out by using the self-developed digital drilling test system. Compared with the results of theoretical analysis and laboratory test, the average difference is 8. 44%, which verifies the rationality and correctness of the rock cutting mechanics model and the DP-cφ relationship. Therefore, a digital drilling measurement method for the rock c-φ parameter is proposed. Compared with the results of this method and traditional triaxial method through laboratory tests, the average difference rate of cohesion and internal friction angle obtained by the two methods are less than 10%, which proves the feasibility and effectiveness of the digital drilling method proposed in this paper. The method is convenient and fast, and can realize in-situ measurement of the c-φ parameter of the rock mass in the field. [ABSTRACT FROM AUTHOR]

Groundwater reservoir technology is a vital way to achieve both efficient mining and water conservation in western coalfields in China. The stability of coal pillar dam is an emphasis of reservoir design, which plays an important role in the stability of groundwater reservoirs. Coal pillar dam should ensure the safety of coal mining, as well as the safe operation of groundwater reservoirs. The stability of coal pillar dam is closely related to water weakening and engineering geological conditions, such as buried depth, mining stress, geological structure and so on. In order to study the strength weakening law of coal pillar dam of groundwater reservoirs under water, this paper took Madiliang mine No.5 in western mining area as the research object, carried out a non-destructive water immersion test on coal sample and a uniaxial compression test on coal sample under various water content and repeated soaking. The results show that the water content of coal samples with various water content increased rapidly within 0-20 h; after 20 h, the grew rate slowed down; and in 20-70 h, the water content grew slowly; in 70-140 h, the growth of water content of coal sample was nearly stable. In conclusion, the water content of coal sample increases with the soaking time, but the increase rate gradually decreases, and finally tends to be flat. With the increase of water content( the number of times of soaking), the uniaxial compressive strength of coal sample decreases gradually, but the peak strain increases gradually, and the elastic modulus decreases gradually. Compared with the dry coal sample, the uniaxial compressive strength of the first water-saturation coal sample and the coal sample with the third soaking decreased by 27.1% and 50.0% respectively, and the elastic modulus decreased by 34.6% and 58.5% respectively. Combined with the above results and the elasticplastic mechanics theory, this paper discussed the damage zone and plastic zone width of coal pillar dam under various water content, carried out the research of coal pillar dam width considering overburden rock pressure, water pressure and water weakening, and designed the width of the groundwater reservoir combining with the engineering geological conditions of Madiliang mine. At the same time, the paper further analyzed the influencing factors of the width of coal pillar dam, concluding that the width of coal pillar dam is closely affected by water content, buried depth, and mining thickness. [ABSTRACT FROM AUTHOR]

In Yushenfu mining area, the concept of water-preserved coal mining is based on the groundwater level decline and vegetation degradation caused by coal mining in the early stage. After theoretical research and engineering practice in many years, a key technical system for water-preserved coal mining has been initially established, which effectively guides the exploitation of coal resources and ecological environment protection in the ecological fragile mining areas. Under the high standards for the construction of national ecological civilization, the ecological environment protection of coal-water resources symbiosis areas in the arid and semi-arid regions of western China is facing a historical test. This paper reviewed the achievements of water-preserved coal mining technology, and concluded that the research on geological conditions, rock movement and water-preserved coal mining methods had basically solved the outstanding problems in single coal seam mining, while the investigation on water and ecological constraints on coal mining, and ecological restoration and reconstruction lagged slightly behind. By combing the relevant contributions, this paper explores the scientific issues in the study of five water-preserved coal mining and related fields. This includes the ecological constraints identification, the quantification and monitoring of the groundwater dependent on the mining area, the detection and prediction of the water conducting fissure zone under the conditions of large mining height and repeated mining, the quantification and evaluation of the thickness of the effective aquiclude, the overburden control and ecological reconstruction and restoration. Under the new situation, the responsibility and tasks of ecological protection in mining areas are significant. More research is needed to support the water-preserved coal mining in western China and promote the construction of green mining areas. [ABSTRACT FROM AUTHOR]

A clear restoration algorithm based on deep fusion network is proposed to solve the problem of over enhancement and insufficient applicability of the existing dust and fog image clear restoration algorithm. The deep fusion network mainly includes three parts, namely, the image pre-processing module, the feature fusion module, and the image output module. The image pre-processing module processes the input image based on the contrast enhancement function, the brightness enhancement function, and the gamma correction function to obtain an image sequence that characterizes different enhancement modes and degrees. Because the local information and global information of image need to be taken into account, this paper proposes a double pyramid module which can realize a dual-path context information extraction on the basis of spatial Pyramid pooling and context information aggregation network. The module consists of two series sub-blocks of dilated convolution, one is composed of a series of small to large scale dilated convolution on multiple scales, and the other is composed of a series of large and small scale void convolution on multiple scales. The image output module mainly processes the features acquired by the feature fusion layer, thereby outputting a threechannel image, that is, a clear image. In order to obtain the training data, this paper builds a large-scale training data set based on the dust fog image formation mechanism with the clear coal mine images. In the process of training, this paper uses the least square error loss function and the content loss function based on VGG network to optimize the network. In order to evaluate the effectiveness of the proposed algorithm based on deep fusion network, six other representative clearing algorithms are selected for comparison. The experimental results show that the proposed algorithm outperforms the other six algorithms in subjective evaluation and objective evaluation, which indicates that the proposed algorithm can effectively solve the over-enhancement phenomenon and improve the clarity and visualization of coal mine images. [ABSTRACT FROM AUTHOR]

In order to solve the problem, that the hard rock fault with a large throw hinders the advance of a fully mechanized mining face, this paper analyzes the disadvantages of the traditional method for passing through the fault and the existing technologie. Also, the paper carries out a systematic study on the deep hole pre-splitting blasting tech-nology for passing through the fault with a large throw. Aiming at the problems of unclear occurrence of fault with a large throw and inaccurate designed path for passing through fault, it puts forward fault occurrence detection technology and the optimized layout for fault detection roadway. Based on the revealed information, the fault strike calculation model is established. Aiming at the problem that deep hole blasting technology is not suitable for working face and groove, it studies the key technology of pre-excavation blasting roadway, and puts forward the layout principle and calculation method of layout parameters of blasting roadway. It determines the scheme of deep hole pre-splitting blasting in blasting roadway, designs the construction method of ear chamber, and solves the problem of concentrated blasting with large amount of explosive. Based on the theory of rock blasting, combined with the characteristics of fault engineering with large throw difference, the blasting parameter selection and calculation method are completed by designing the hole diameter, hole depth, charge mass, plugging length, hole layout and blasting vibration safety control. The underground roadway of 2302 N working face at Xinjulong Coal Mine reveals a hard rock fault with a comprehensive drop 12. 5 m. Through the exposure points of lower roadway and six detection holes arranged in sequence, the initial strike of the fault extending to the working face is verified, and the vertical strike of the fault, the driving scheme along the floor of the coal seam and the driving scheme along the floor of the coal seam under the fault are designed. Based on the measured information, it plans the path through the fault. According to the change of fault occurrence in the path, it divides eight blasting regions, designs the blasting layout parameters in each region, and predicts and analyzes the blasting effect by means of numerical simulation. The application results show that the blasting fissure penetration effect is good, the consumption of shearer picks through the fault is reduced by 40%-50%, and the time is reduced to half compared with the time using traditional method through the fault. The technology for passing large throw fault have been successfully applied in many working faces in Xinjulong coal mine. It has achieved good results in ensuring high efficiency continuous mining, reducing the cost of passing through fault and ensuring blasting safety. The practice has proved that this technique is widely applicable in dealing with large throw fault at a fully mechanized mining face. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to solve the problem of determining the key parameters of filling mining under different geological and mining conditions. Based on multi-span statically indeterminate structure, the ‘roof-supportfilling body’interaction mechanics model with basic roof was established under the condition of actual deformation form of filling mining strata movement. In this model, the coal wall and filling body are main supporting bodies, while filling supports define the deformation of the basic roof. According to this model, the mechanical equilibrium equationand deformation coordination equation of the continuous roof was established to solve the problem when the pressure of the filling supports is unknown, which changed the simplified analysis method of thinking of the roof pressure as a uniform load in the previous mechanical models. The elastic foundation of the filling body was dispersed into a number of equivalent elastic supports, and the single-span isolator was analyzed to establish the section deformation equation. Then the matrix expression of section deformation equations was obtained, which contained n+2 deformation equations and formed n+5 solving equations with three equilibrium equations, corresponding to n+5 unknown constraints. In order to reflect the distribution of roof load more accurately and analyze relationship of roof, supports and filling body more reasonably, this paper attempted to combine the mechanical model with the numerical model to solve this problem. Then a numerical model with same parameters of the filling supports and filling body in above mechanical model was established. The stress curve calculated by the numerical model was used as the roof pressure q(x) and substituted into the ‘roof-support-filling body’interaction mechanics model. Therefore all the support reactions, internal force and moment of beam in the model could be solved, and the mutual interaction relationship between the roof, the supports and the filling body was obtained. The variation law of the support strength of the front and back canopy of hydraulic supports with double canopy structure under condition of different elastic foundation coefficient of filling body and different roof deformations was analyzed by a specific calculation example, providing an effective method for the determination of key parameters of filling mining. [ABSTRACT FROM AUTHOR]

Currently more coal resource is buried in deep and more high-quality resource is located in the west of China. It makes a deep mining and a mining in the west become the new normal of coal resources exploitation. Thus a green mine construction, green mining development and green mining propulsion are imperative. This paper puts forward a"mining-dressing-backfilling+X"technical conception of green mining of coal resources. That is an underground integrated production system, which is integrated coal mining, coal-waste separation, and gangue backfilling with "active control of strata movement, gob-side entry retaining, gas extraction, disaster prevention, water-preserved-mining". The system forms a coal mining-dressing-backfilling+X(control, retain, extraction, prevention and preserved) collaborative production mode. The paper defines the"mining-dressing-backfilling+X"technical connotation and framework of greenmining, expounds "mining-dressing-backfilling+X"evolution of four generations, analyzes the specific technical advantages of its practice of green mining and gives the scientific engineering design method. The paper elaborates five aspects of typical "mining-dressing-backfilling + X"technology corresponding technical principle, engineering requirements, design process and methods, key technology and process equipment. Engineering practice of the Tangshan Coal mine, Zhaizhen Coal mine and 12 th Coal mine of Pingdingshan Group has respectively proved that "mining-dressingbackfilling+ control", "mining-dressing-backfilling + retain", "mining-dressing-backfilling + extraction " technologies have a remarkable technical superiority and the engineering demonstration effect. "Mining-dressing-backfilling + X "green mining extension in the future combines "mining-dressing-backfilling+processing", "mining-dressing-backfilling+intelligent", "mining-dressing-backfilling+adjustment"and "mining-dressing-backfilling +coordination". The overall formation of the "mining-dressing-backfilling+X"technology system can provide a strong technical support for the realization of green mining of coal and associated resources. [ABSTRACT FROM AUTHOR]

To boost the exploitation of energy resources in no manpower(little manpower) and to guarantee the demand of national energy and strategies, a complete integration of information technology and the theories of mineral resource exploitation is the direction for the revolution of energy resources development in the new era. A new round of information technology revolution occurs in the areas, such as big data, cloud computing, artificial intelligence, internet of things, regional chain and internet, and intelligent unmanned exploitation in coal, uranium, and oil and gas. In considering the integration of information technology, the scientific conception of precise mining of coal and its associated resources was innovatively developed in this paper. The innovative geospatial physical science, multi-phase and multi-field coupling theory and intelligent control system are proposed as a core guarantee system. supported by the "trinity"scientific research means including internet+on-site monitoring, physical/numerical simulation and basic experiments. The holographic real-time display of coal and associated resource endowment, original/disturbed geological disaster and the working condition of mining equipment is required. Also, the intelligent and flexible decision on mine planning, operation management and the ecological restoration of closed mines, the intelligent depth perception, accurate delineation and efficient resolution of the crisis for potential disaster, the self-repair of the damage space, the resilience recovery of control system, the adaptive adjustment of the equipment are all need to be achieved. Precise mining of coal and associated resources can effectively solve all these major problems subjected to exploration and monitoring, collaborative development, disaster prevention and control, and negative environmental externalities, to provide new ideas for the future development of coal and associated resources. In this paper, five key scientific issues and seven main research directions for the precision mining of coal and associated resources are summarized, and a phased plan is proposed for the safe, efficient and green mining of resources in the new era. [ABSTRACT FROM AUTHOR]

Based on the full analysis of the present situation at home and abroad, this paper puts forward the concept and core content of transparent mine and five principles to be followed in constructing transparent mine.Based on the latest development of spatial information technology, the paper expounds the architecture of transparent mine system including three-dimensional engine layer, intelligent coal mine platform layer and production operation layer,and introduced the solutions of the key technical problems of three-dimensional spatial modeling criterion for coal mine, the storage and integration of multi-source spatial-temporal data, the construction and dynamic modification of high-precision geological models, the three-dimensional visualization of massive data,and mechanical and electrical equipment modeling and simulation and three-dimensional automated remote control. Those establish a solid foundation for transparent remote management and control of coal mines.Some technologies have been applied in Yangquan Coal Industry (Group) Co.Ltd. [ABSTRACT FROM AUTHOR]

To overcome the problem of parameters calculation for optimal segmented Knothe time function, two calculation methods are presented. Firstly, based on the surface monitoring data of a mining area, or mining areas with similar geological and mining conditions, the back-calculation and comparison method of parameter determination is proposed. It gives a detailed parameter calculation process, which is intuitive, easy to operate, and versatile, and can also be used to obtain the parameters for other time functions. Secondly, based on the surface subsidence law when the goaf reaches its full mining size, and the corresponding probability integration parameters, a"direct calculation method"of parameter determination is proposed. The parameters of the method are clear in meaning, and the process of parameter calculation is convenient and can be directly applied to program calculation. Through the dynamic prediction practice, it is shown that the maximum relative error of the dynamic prediction can be controlled within 9% using the method described in the paper. With the increase of mining time, the dynamic prediction accuracy will gradually increase and it will eventually be maintained at around 5%. According to the statistics, the relative prediction error of the maximum surface subsidence can be maintained at around 6%. Application practice proves the practicability and reliability of the method proposed in the paper. [ABSTRACT FROM AUTHOR]

Based on eastern slope constructing dump at an open-pit mine in Xinjiang Uygur Autonomous Region, using the orthogonal method to establish an experiment program, this paper performed a basal contact friction experiment to simulate slope failure, and the experiment of four typical production model fully reflected the failure process of composite slope. Experiments show the 21 st coal floor is the key factor of slope failure. By analyzing the displacement of monitoring point, there are four kinds of potential sliding surface including line, straight line, broken line and circular arcs and two kinds of failure classified into subsidence and creep-crack. The paper discusses the effect of weak layer, time and dump on slope, points out the improvement for basal contact friction experiment, and proposes a reasonable reinforcement time for stability and the importance of reasonable making model. Overlying dump have dual influences on slope stability, which controls the scale of potential sliding mass together with weak layer. The research can be applied to the prevention of multi-seam and soft rock slope in open pits. [ABSTRACT FROM AUTHOR]

The conventional study on scraper conveyor chain working condition only considers the bilateral same load chain working condition.This paper mainly studies the single side chain condition and its effect on the vibration characteristics of the scraper chain system torsional pendulum.The cause of the chain failure and the way of applying the load simulation are analyzed.Also,the paper investigates the mechanical model of scraper conveyor chain working condition,selects Voigt model to establish the dynamic model of scraper conveyor torsion pendulum vibration,uses Matlab software to establish dynamic equation and state equation,and constructs a function subroutine to the established dynamic equation.The preprocessing of dynamic analysis is realized.The vibration speed,acceleration and tension of the torsion pendulum of the scraper chain system are obtained by simulation analysis under four different working conditions of different materials before and after the chain position,and the experimental results are verified. The results show that the chain process will cause a strong torsion vibration of the scraper chain system,and the torsional pendulum vibration is more obvious when there is no material at the beginning.In the case of both front and rear materials,the vibration of torsion pendulum weakens slightly. [ABSTRACT FROM AUTHOR]

Mine hoisting pulley has an important role of guidance and support in hoist system. However, under the work environment with overload, high altitude,dynamic load and changeable, there are some affecting factors, such as not synchronized in the rope cycle, and unequal line, which make the rope groove frayed, and cause secondary damage to new ropes, and endanger the service life of rope and pulley. Therefore, this paper establishes and analyzes the mathematical model with eccentric error and position error, and obtains the relationship between the error of feed and some parameters, such as feeding, the size of original rope, he eccentric error, the height of cutting tools to install platform, the original rope size and angle of machine tool. This paper determines the optimal design parameters with the distance from the turning device installation plane to the pulley axis is 1 m, the distance from cutting head to the installation plane is 0. 6 m, and the angle is 60°. This paper uses two axes linkage and three-dimensional drive system to design the device ontology based on "servo motor+ball screw pair", and uses the integral frame positioning to design the hanging bracket. The hanging bracket fixes the ontology on the lower triangular position of the head sheave platform. The static and dynamic simulation analysis show that the designs of device body and bracket are feasible. The experimental research shows that the device can better turn the rope pulley groove, and the radius of the rope after turning is 1648. 05 mm, and the position of the circumference is 10. 355 m, and the turning accuracy reaches 10-3. The ropes have good consistency, and eliminates the wear peak. [ABSTRACT FROM AUTHOR]

Mine transient electromagnetic method has a low resistivity problem for using minor transmitter and receiver loops, which leads to data interpretation difficulties and decreases detection depth. Firstly, this paper studied the variation of secondary field with transmitter-receiver distance through numerical simulation and field test, and found that the simulant secondary field was almost unchanged with transmitter-receiver distance within 20 m while measured data decreases linearly in logarithm coordinate system. Theoretical analysis shows that the mutual induced electromotive force is the main component of measured data, which leads to low resistivity problem. Furthermore, the paper proposed a resistivity correction method based on the different properties of secondary field and mutual induced electromotive force. The method eliminates the mutual induced electromotive force by using two measured data with different transmitter-receiver distances. Finally, the proposed method was successfully used in a half-space field case and a whole-space field case to demonstrate its practical usefulness. [ABSTRACT FROM AUTHOR]

The geological characteristics of coal-derived gas resources in Linxing and Shenfu area show a multi-layer system vertically, a superposition and mutual occurrence of lithology, as well as the development of thin interlayers and a low effective rate by monolayer fracturing within these thin interlayers or directly/closely-contact layers. A multilayer fracturing technology for exploring and developing the coal-derived gas resources was introduced in this paper. By numerical simulation method,the paper studied the influences of cementation strength and dip angle of interface, stress difference between layers,fracturing operation displacement and other factors on fracture propagation. Also,the fracturing operation parameters were optimized, then a suitable reservoir conditions for multilayer fracturing was determined. Based on rock crack criterion and interface fracture criterion,a multilevel evaluation model of multilayer fracturing feasibility in coal-derived gas reservoir was finally established, with factors like coal structure, interface mechanics and stress field taken into account. The study has a certain guiding significance to the application of the multilayer fracturing technology. [ABSTRACT FROM AUTHOR]

Focused on scientific utilization of underground space in coal mines, the capacity of underground space in China is analysed systematically for promotion of underground space utilization. The distribution diagrams of available underground space in producing coal mines, available underground space in coal mines within 50 km far from prefecture-level cities and available underground space of tunnels in closing coal mines are produced for the first time. Based on a method proposed for identification and estimation of underground space, volume of available underground space in coal mines is estimated in the paper. A condition of surround rocks is evaluated for various functions of development and utilization of underground space. Then six design principles and four design concepts are proposed for development and utilization of underground space in the paper. New orientations, technologies and conceptualization for development and utilization of underground space are also suggested in a systematic viewpoint. In addition, on the basis of volume of underground space, closing sequence of coal mines and construction conditions in Western Beijing, the idea of development and utilization of underground space of coal mines in Western Beijing is proposed as a typical case in the paper. [ABSTRACT FROM AUTHOR]

In the Upper Permian coal bearing strata of Liupanshui Coalfield, there were coal seam, shale and sandstone overlaid frequently. In order to have an overall plan and exploration on the natural gas in different reservoir and to favorably reduce the resources wasted and improve the development benefit, with the study on the lithofacies, thickness and source rock geochemistry of the coal measure gas reservoir, the reservoir physical property and the spatial occurrence law, this paper analyzed the reservoir formation potential of the coalbed methane, coal measure shale gas and the coal measure tight gas in Liupanshui Coalfield and discussed the space overlaid relationship and exploration prospects of the coal measure gas. The study results showed that within the coalfield, the coal rank of late Permian coal seam was complete, the thickness was high, the metamorphic grade was generally higher, and the gas content was good. The gross thicknesses of the shale and the sandstone were high, the organic geochemistry and reservoir physical parameters were good. The difference was high in regional and horizon distribution of different lithology, the lithological combination types varied, and the space disposition was beneficial to the development of many vertical natural gas reservoirs. The favorable exploration horizon of the coal measure shale gas was the lower section of the Longtan Formation and the favorable horizon of the coalbed methane and the coal measure tight gas was the Wangjiazhai Formation and the up section of Longtan Formation. Based on the circumstances, totally three major gas reservoir types, including the “resources and storage integration” independent coal measure shale gas reservoir, “resources and storage closed neighbor type” coal measure “three gas combined gas reservoirs” and “bottom resources and top storage type” coal measure “two gases combined gas reservoirs” were summarized and provided. The paper preliminarily concluded that Qinglong Syncline deep section would be the priority exploration zone of the coal measure shale gas, Qingshan Syncline deep section would be favorable to the co-exploration and co-mining of the coalbed methane and the coal measure shale gas, Panguan Syncline and Gemudi Syncline deep section would be favorable to the co-exploration and co-mining of the coalbed methane and the coal measure tight sandstone gas. [ABSTRACT FROM AUTHOR]

As a new power transfer mode,wireless power transfer(WPT) via coupled magnetic resonances brings great convenience to the industrial,medical and life field.However,the traditional symmetrical coil structure has limited the applications of WPT technology in the fields with special needs,such as the field of the mine and medical.Based on the WPT system with asymmetric coil structure proposed by predecessors,the paper analyzed the effect of the ratio of transfer distance to radius,the ratio of the radius of the two coils and angular misalignment of the non-parallel coaxial coils on the transfer efficiency of WPT via coupled magnetic resonance and the mutual effect on efficiency among each factors.Simulation results shows that,the larger the ratio of the transfer distance to radius is,the smaller the range of the angular misalignment will be.And the effect of angular misalignment on the transfer efficiency is more gentle.With the increase of the ratio of transfer distance to radius,the efficiency increases first and then decreases,and when the angular misalignment is around 80°,the effect is the greatest.And the effect of the ratio of the radius of the two coils on transfer efficiency is related to the angular misalignment and transfer distance.The experiment results show that the theoretical analysis of the paper is correct,which providing an useful theoretical reference for the design and further research on the WPT system in complicated environment. [ABSTRACT FROM AUTHOR]

In order to study the influencing factors of the recombination circulation ventilation,the structure of recombination circulation under different wind speeds in the deep sunken open-pit mines,this paper qualitatively analyzed the recombination circulation ventilation through similar experiment and numerical simulation.Using the methods of dimension analysis and multivariate nonlinear regression analysis,the criterion equation for the decision parameter (K) of recombination circulation was obtained.The accuracy of the decision parameter was verified by grey correlation analysis.The results indicate three points:① The geometrical parameters such as the slope angle,depth and long axis of the open-pit mines are the main factors influencing the existence of the recombination circulation in the open-pit mines;② When the decision parameter of the recombination circulation ventilation ranges from 2.9 to 7.0,the recombination circulation ventilation will all be produced in the open-pit mines;③ Compared with the traditional decision parameter,it is more accurate for the decision parameter K with the slope angle to represent the recombination circulation ventilation.The result in this paper could further improve the ventilation theory of open-pit mines. [ABSTRACT FROM AUTHOR]

Considering that the conventional chain safety factor is calculated according to the external load of two chains, and the actual situation is that the load of two chains is uneven, this paper studies the calculation method of the operation resistance of scraper conveyor based on the material distribution characteristics. The frictional resistance of the coal material and the bottom of the central trough, frictional resistance ol the coal material and the retaining plate, and the frictional resistance of the moving coal material and the static material on the wall side are deduced theoretically. The calculation formula of the running resistance of the scraper and chain is obtained under different load conditions. Based on the simulation test rig of fully mechanized complete sets of equipment constructed by National Energy Agency Research and Development (experimental) Center,this paper investigates the operating resistance calculation method on the basis of the material distribution characteristics. The research results show that the computational method and the error of experimental data are within the allowable range. In this paper,the calculation method of the operating resistance of scraper conveyor based on the material distribution characteristics provides the basis for the chain life prediction and the safety factor calculation under the influence of offset load. [ABSTRACT FROM AUTHOR]

To study the supporting performance of two-legged shield support and its canopy adaptability to the roof,the mechanical model of load equilibrium region under single region loading condition was constructed. This paper analyzed the distribution characteristics of the canopy load equilibrium region during full-height range and studied its influential factors. Subsequently, combined with the actual conditions of the supports,the paper analyzed the limit load equilibrium condition of canopy under double region loading condition, which further extended the theory of canopy equilibrium region. Finally,the multi-body dynamic model of a hydraulic support was constructed by using ADAMS,the single and double region loading conditions of the hydraulic support were simulated respectively. By comparing with the theory, it shows that improving the loading condition of the hydraulic support, optimizing the parameters of the equilibrium jack and the legs can improve the adaptability of the shield support effectively. [ABSTRACT FROM AUTHOR]

To overcome the difficulty in real-time forecasting and prewarning of coal mine composite dynamic disasters,the paper investigated on the occurrence mechanism of composite dynamic disasters and the relevance to prewarning signals,by dividing prewarning signals into universality and individuality prewarnings and corresponding them to monitoring parameters,through which key monitoring parameters of real-time,mid-time and long-term prewarning are proposed.Real-time prewarning platform of composite dynamic disasters is mainly composed of monitoring hardware,analysis software and prewarning methods.Monitoring hardware mainly includes dynamic disaster monitoring system and platform monitoring room facilities；and analysis software refers to a platform's data collection and analysis software；and prewarning methods include multiple methods like composite disaster joint warning methods and single parameter and multi-parameter joint warning methods.Based on the above studies,basic research and forecasting and prewarning research on coal mines in Henan,Shangdong and other provinces,where composite dynamic disasters may happen,are taken,and coal mines' composite dynamic disasters are forecasted.Besides,the paper also forecasts the development tendency of real-time forecasting and prewarning platform of composite dynamic disasters. [ABSTRACT FROM AUTHOR]

To overcome the technical problems encountered in the mining process at a fully mechanized mining face with large mining height,this paper puts forward three scientific problems facing fully mechanized mining face with large mining height.Based on the technical and economic analysis of thick coal seam mining method,an adaptability evaluation index system and evaluation model are established.Based on the principle of strength coupling,rigidity coupling and stability coupling between hydraulic support and surrounding rock,a coupling dynamic model of hydraulic support and surrounding rock and a “cracking,slip” mechanical model of coal wall spalling are also developed.In addition,the paper puts forward a “double factor” control method for determining reasonable working resistance of the fully mechanized hydraulic support with a large mining height.Based on the contradiction between caving and stability control at a fully-mechanized top-coal caving face with a large mining height,a method of increasing the hydraulic support setting force and improving the structure of hydraulic support are put forward to relieve the contradiction between them.The safe,efficient and high recovery rate of thick coal seam mining is realized by developing the key technology and equipment for thick coal seam. [ABSTRACT FROM AUTHOR]

Sustainable mining refers to extract coal economically,efficiently and with a high recovery rate while ensuring safety and within the allowable range of environmental capacity.This paper again clarifies the connotation and technological system of sustainable mining from the relationship between human and nature of coal acquiring,consuming and returning.Additionally,the paper reviewed the developments of the coal industry under the guidance of sustainable mining in China,analyzed some problems of sustainable mining in the new situation,illustrated the necessity of developing sustainable mining and put forward the conditions of comprehensively realizing sustainable mining.The top priority should be accomplishing the top-level design of sustainable coal mining by setting new standards for the entrance of new coal mines into the coal industry and the elimination of outdated coal mines out of the coal industry,implementing the sustainable capacity step-by-step,strengthening industry coordination as well as improving policies and regulations.At the same time,we should also enhance the study of economic law of coal resources,increasing the investment in science and technology and tackling key problems in technology,reforming the personnel training mode.Proposed directional suggestions for sustainable mining and healthy development of coal industry. [ABSTRACT FROM AUTHOR]

In this paper,based on the secondary development of the LS-DYNA,a user-defined statistical damage model was implemented.The stress and damage distribution of conventional circle hole and notch hole were compared.Results demonstrate that two mechanical effects are induced by the notch.High stress concentration is generated at the edge of the notch and the stress at the other part of blast hole is reduced.The sensitivity analysis of notch angle and depth were carried out.Results reveal that the most perspective angle is 60°.The threshold value of notch depth exists,while the control effect of damage is not obvious when the depth is bigger than the threshold value.The rock strength affects the selection of the best depth significantly.As the rock strength increases,the depth is larger.The research results of this paper have important engineering application value. [ABSTRACT FROM AUTHOR]

Aiming at the characteristics that series of environmental and ecological problems must be accompanied during opencast mining operations,the authors propose the concept of surface mining disturbance effect quantification and evaluation.This paper expounds the connotation and characteristics of Surface Mining Disturbance Index (SMDI).The SMDI is a comprehensive index which considers ecological damage and repair,mining technology and process optimization,energy consumption structure optimization,pollutant emission and treatment,production management and other aspects of the problem,uses multi-disciplinary theory to solve the difference between resource conditions,mining conditions,regional,coal and pollutant types etc.Ultimately,the system uses the numerical number between -100 to +100 to make an evaluation or prediction of SMDI temporal and spatial variation.This paper studies the basic principles of constructing the evaluation index system,and puts forward the basic framework of the index system,which includes 2 categories of all the 23 evaluation indexes,and points out the synthetic method of the SMDI. [ABSTRACT FROM AUTHOR]

The paper intends to comprehensively solve the problem of the low recovery rate of super-long two-entry longwall panels,difficulty maintenance of secondary mining roadway and need to jump in the gob-side entry.First of all,the patent put forward “A Gob-Side Entry Driving Method in Super-long Working Face”,and determined several key parameters.Secondly,the paper adopts the methods of theoretical analysis and field measurement to determines that the gob-side entry is arranged at a distance of 12 m away from the goaf.The distance of heading face behind the working face isn't less than 1 200 m,and that ahead of the next face is not less than 190 m.The method can avoid mutual interference in the mining.Finally,under the conditions of actual engineering background,it determined the 40 m coal pillar in the original method and occurred large deformation in the secondary mining roadway,which can not meet the production requirements.If roadways use the roadway driving technology,it will be getting huge economic benefits.The conclusion can provide certain reference for the mine with similar geological and mining technology conditions. [ABSTRACT FROM AUTHOR]

Transient electromagnetic advanced detection method is an effective way to explore goaf which regards as a vital threat to coal mine safety and miner's life.But its application effect is influenced by the roadway environments.This paper presented an operating method which adopts a rotated transmitting terminal located in roadway orifices and three-component receiving terminal located in down-hole.By analyzing the feature of down-hole data using 3D FDTD,this paper presented a technology to synthesize and adjust the three-component down-hole data along with the normal direction.The decline phase’s completely period apparent resistivity,after the peak point of down-hole data,was calculated using binary search algorithm.Different hole depth data,in 3D numerical model,was processed to isolated and superimposed imaging.The imaging results showed that it has acquired favorable effect in exploring goaf in front of the driving face.In order to test the practicability and availability of this operating method in detecting goaf's shape,characteristics and dimensions,the author's research group has conducted an engineering test in Shanxi's coal mine.The research showed that dynamic source and fixed reception roadway-borehole TEM detection method is a great combination of underground geophysical exploration technology and drilling technology,and makes them supplement to each other.It is an effective application in goaf detection [ABSTRACT FROM AUTHOR]

The traditional grid method for extracting road network has a low accuracy,especially for the extraction of open-pit road network,the loss and offset of road is more significant.For solving this problem,the conventional solution is to enlarge the grid so that the connectivity can be ensured.However,in this paper,by assuming the GPS bias as a normal distribution,a method of rastering the GPS data by calculating the probability of track points on the road was proposed.On this basis,the median filter algorithm was deployed to preprocess the raster image.The index table thinning algorithm was improved,and this improved thinning algorithm was used to refine the grid image of the road network.Finally,the road network was translated into vectorization.Experimental results show that the coverage ratio of this method has been improved by 6.43% to 11.54% compared with the traditional grid method,and the error rate has been reduced by 42.13% to 83.02%.This paper provides an effective method for road network extraction and reveals the important influence of grid size on road network extraction results. [ABSTRACT FROM AUTHOR]

To study the influence of movement trend,mechanical state and shield beam structure after the shield beam under impact load,the paper uses a multi-body dynamics software ADAMS to establish the numerical sim-ulation model of hydraulic support. In the model, the shield beam is set as flexible by pre-processing software Hypermesh, the leg and balance jack are replaced by the spring damping system equivalently, the stiffness of the leg is set as the variable stiffness,initial support force is provided by the preload of the equivalent spring,roof pressure is applied vertically to roof through a static load,the impact load caused by immediate roof and main roof rock falls on the shield beam is replaced by the step load. Based on the above model,the paper analyzes the horizontal forward displacement of canopy, the contact force variations between canopy and roof, the force variation of each hinge joint and shield beam stress change when the impact load acts on the different positions of the shield beam. The results show that the different position of load caused the different various trends of hydraulic support. This is of great significance for the stability control and equal strength design of hydraulic support. [ABSTRACT FROM AUTHOR]

Aiming to research the feature and performance evaluation method of random load spectrum, this paper presents three methods to describe the characteristics of the energy spectrum, including the gradient of the energy accumulation, the amplitude increment and the energy based on experimental transient load and meso-feature, and the meso- feature of random load spectrum are used to deduce the macro-cutting performance evaluation. In this paper,taking the mechanical process of cutting coal and rock as example, entropy theory is applied to analyze the correlation of random load spectrum,and the mathematical model of the feature entropy and the weighted entropy of the random load spectrum are proposed to discuss the feature and effect of crushing load spectrum of coal and rock in the time domain. The results show that the load spectrum entropy is increased with the rotational speed increase at the same maximum cutting thickness,it reveals that the disorder degree of the load spectrum is also increased with the rotational speed increase ,and illustrates the relative trend of coal-rock fragmentation and dust content, moreover, there is a positive correlation between the characteristic entropy and the weighted entropy of the load spectrum and the specific energy consumption and the degree of fragmentation. Hence,the proposed load spectrum entropy model and algorithm can be used as an effective method for the cutting performance evaluation. [ABSTRACT FROM AUTHOR]

With the long term exploitation of coal resources, the progress of coal mining technology and energy structure change in recent years, more and more closed mines are generated. Currently the main measures taken by the abandoned coal mine are the restoration of mine environment, resulting in many social, economic and ecological problems. This results in a lot of waste of resources. How to solve the problems left by the mine in order to realize the successful transformation and upgrading of the mine, which is of great strategic significance to the development of the coal industry and the national economy. This paper analyzes various types of resources and introduces the current situation of China s transitional mines, including the buildings of abandoned industrial square, development and Utilization of abandoned lands ( industrial square lands and subsidence area lands) and mining garden construction. And pointed out that the use of domestic waste coal resources development and utilization is not sufficient, high operating costs, especially the development and utilization of underground space resources is low. Such as shaft, roadway, chamber and other underground space resources, almost all waste after the closure. Therefore, aiming at the problem of low utilization rate of space resources in the transition coal mine,the paper analyzes the new direction of the exploitation and utilization of coal mine underground resources,such as the use of coal mine underground resources to store oil and natural gas, build energy storage stations and underground cities, which provide a new idea for the development and use of these closed coal mines. [ABSTRACT FROM AUTHOR]

Due to the environment of coal mine space is affected by grime，the images obtained by video surveillance have low illumination，non-uniform illuminance problems，and the existing algorithms cause color distortion or excessive enhancement in dealing with non-uniform illumination mine image，which is not conducive to the interpretation and application of images. With the actual images data，this paper proposed a new non-uniform image enhancement algorithm based on illumination adjustment combining with Guided Filtering and “S Curve” function，which may overcome the problems of the existing algorithms. By analyzing the characteristics of the video images，a multi-scale guide filtering，which can preserve the edges and corners，is adopted to get the illumination component. Then based on Retinex theory，the image is decomposed into an illuminance component and a reflection component. Regarding the non-uniform illumination，a new S-shape curve function is proposed to adjust the illuminance component. Considering the image has a relative low contrast，the contrast limited adaptive histogram is further used to enhance the contrast. Finally，a new image enhancement method is proposed with the detail enhancement coefficient and the illumination enhancement coefficient achieve a better enhancement performance of non-uniform images. Compared with the other four algorithms，this paper shows that the proposed algorithm is superior to the above algorithms both in subjective evaluation and objective evaluation. Finally，this algorithm can effectively enhance the overall image brightness and contrast，while avoiding excessive enhancement phenomenon of the bright region generated near the light，showing the superiority of the algorithm. [ABSTRACT FROM AUTHOR]

Rock burst occurring in deep coal roadway is a technical problem to be solved, 85% of which occurs in the roadway, and its frequency and intensity increase dramatically with the increase of mining depth. This paper analysis the instability mechanism of deep coal roadway roof based on the elastic-plastic mechanics and fracture principle, expounds the rupture instability mechanism of roadway roof strata with increasing stress and energy, derives the load, deformation and energy conditions of rock burst, and elaborates the fission instability evolution law of composite roof which turns roof into the vicious circle of "interlayer separation-rock beam cracking-dynamic crack by dynamic load" or even instant caving. The instability process of deep coal roadway roof is closely related to the cooperatively extension of six main cracks under the superposition action of high stress and dynamic pressure. The six cracks of "one horizontal and five vertical" extend together and form a "door" -like breaking block to push into roadway and cause damage. The paper presents the six manifestation pattern of rock burst and dynamic instability, puts forward the effective unit control timbering countermeasure of ‘‘roof truss cable+roadway center long cable+roadway drift angle bolt”. [ABSTRACT FROM AUTHOR]

A large number of field engineering practice indicate that the movement of thick alluvium rock strata has a large difference with that of bedrock. At present，the rock strata movement laws mainly focus on two aspects. Strata control above working face mainly researches on the fracture and movement laws of roof rocks with a certain height at one side. However，the geology and survey engineering mainly researches on the subsidence laws of surface thick alluvium at another side.In this paper，the authors try to combine the two research areas and develop a new rock strata movement model，which can accurately reflect the true movement law of overlying strata. Based on the initial and periodic fracture mechanical models of bedrock，the distribution of principal stress and the fracture trace have been obtained. And the inverse funnel-shaped failure mechanism is the main failure mechanism of deep bedrock. The funnel-shaped movement mechanism of shallow thick alluvium has been discussed in detail based on probability integral method and shear-slip theory. Combined the two aspects of researches，the paper proposes that the movement of overlying strata with thick alluvium has the feature of analogous hyperbola. In addition，the analogous hyperbolic movement model is proposed to characterize the movement of overlying strata with thick alluvium. The new model can be used to predict overlying strata’s subsidence range. The Mining Discontinuous Deformation Analysis (MDDA) has been developed and applied to simulate the movement of overlying strata with thick alluvium. Numerical results indicate that the analogous hyperbolic movement laws can also be founded，which is approximately consistent with the theoretical model. [ABSTRACT FROM AUTHOR]

In order to promote the mine environmental restoration work, this paper put forward the definition of geo-environmental restoration model. It discussed the mine environmental restoration governance theory based on the complexity of mine environmental problems, which are the objectives, core technology and model construction. With the method of layer analysis, the dominant of restoration work is found；then the governance targets are divided and decoded into the objective of geological engineering, land-restoring and ecology-restoring；it summarizes four restoration technologies, including the misfortune-repairing technology, engineering repair technology, ecological restoration technology and bioremediation technology；finally, it puts forward a restoration governance model which is to-the-point, target-controlled and technology-determined. Take the coal mine subsidence basin as an example, this paper puts forward the objectives, requirements and techniques of restoration work in subsidence basins, and it constructs five mine geo-environmental restoration models for subsidence basin problems. In two coal mine subsidence basins of Inner Mongolia and Hebei Province, the management were taken appropriately according to the local condition and the effects of restoration subsidence basin model were analyzed in the practical engineering. [ABSTRACT FROM AUTHOR]

Based on the strength degradation law of surrounding rock obtained from some experimental data, the strain softening model in FLAC3D was improved by a secondary development. The mechanical parameters of surrounding rock were derived by an inversion method using the measurement data of mine pressure as characteristic values. This paper proposed the assessment index for the effectiveness of borehole destressing, and the classification criteria for destressing degree. Through a systematic study about the effects of borehole parameters (length, diameters and inter-row spacing) on the stability of surrounding rock of deep roadway, the paper put forward a method to determine the key parameters influenced by borehole distressing, and then improved the technical system of borehole distressing. The practical application shows that the application of the borehole schemes determined by the proposed method can control the surrounding rock effectively. The method is simple to be mastered. [ABSTRACT FROM AUTHOR]

This paper presents a numerical simulation of quicksand or sand flow hazard through the broken rock mass in the caving zone due to coal mining based on DEM.The panel 22402 of the Halagou Coalmine was taken as the study site in this paper. The fragment-size distribution of caving zone was analyzed by using the fractal theory and then a numerical model of quicksand through the broken rock mass of caving zone with random shape was constructed by using DEM according to the fragment-size distribution. The simulation results show that the caving zone with large voids or pores and good connectivity are the dominant pathways for sand migration；the voids and pores in the caving zone can store the aeolian sand. The poorly graded rock mass in caving zone has a certain effect to block the sand flow；the velocity profiles of sand flow are of spindle type which mean that the sand flow velocities along the centerline are larger than those near the wall. [ABSTRACT FROM AUTHOR]

In the present paper，the authors conducted experiments on the samples of the soil of the Daquanhu coal fire at different temperatures (25，50，70 ℃) for analyzing the adsorption and desorption characteristics of typical heavy metal to the soil layers (Ⅰ，Ⅱ，Ⅲ，Ⅵ，Ⅴ，Ⅳ) at different depth for the same sampling site of the fire zone. Results show that the amount of adsorption of As to soil increases with the increase of As concentration added to the soil. And it also varies up and down with the increase and decrease of temperature. Desorption of As varies up and down with the same trend of the adsorption. With the experiment data，the authors fitted the trend of the isothermal adsorption of typical As to these soil layers by using the Freundlich model. The key parameter KF for this model，which indicates the capacity of As adsorption to soil layers，was quantified as different equations for each soil layer.At the temperature of 25 ℃，the parameter KF for each layer has the trend of Ⅳ>Ⅴ>Ⅵ>Ⅲ>Ⅱ>Ⅰ，which shows the same change as the change of the CaCO3 content for each layer.At the temperature of 50 ℃，the parameter KF for each layer has the trend of Ⅳ>Ⅵ>Ⅲ>Ⅴ>Ⅱ>Ⅰ，which shows the same change as the change of the pH value and the CaCO3 content of soil layers. At the temperature of 70 ℃，the parameter KF for each layer has the trend of Ⅰ>Ⅲ>Ⅱ>Ⅵ>Ⅳ>Ⅴ，which shows the opposite change with the change of the pH value. With these soil samples，soil columns for each layer were established，including a column for the integrated soil layer with all layers. Result from leaching experiments show that the releasing rate of As was fast at the beginning of leaching which indicates the As move downward quickly with the leaching liquid movement. At the middle and late stage of leaching，the releasing rate reduces slowly to reach an equilibrium sate.In the present paper，numerical simulations also were made to study the change of migration of As at different conditions，i.e.，the inner As adding condition，the surface As adding condition，and the external As adding condition. Single layer simulation shows the same movement of As as the experiments which verified the reliability of simulation method. Integrated soil simulation shows that the As content within the soil column increases with the increase of temperature which indicates the soil temperature is the major factor for the As migration. [ABSTRACT FROM AUTHOR]

Taking the Dananhu mining area located in Turpan-Hami basin as an example，combining with the typical characteristics of Jurassic coal bearing strata，such as good permeability，strong water content，and large reserves，using the methods such as field sampling，pressure mercury test，scanning electron microscope，the authors systematically studied the characteristics of water bearing medium in the aquifer of Jurassic System Xishanyao Formation including sedimentary environment，macro-formation structure and meso-pore structure. Based on the field pumping test and the analysis of data processing，this paper studied the circulation conditions and hydrodynamic characteristics of the aquifer. The results of this study show that the study area of Jurassic aquifer has a typical sedimentary environment of buried ancient lake bed and a special hydro-geological structure characteristics of high porosity，strong permeability，the double aqueous medium of “porosity and fracture”. In regional area，due to the Jurassic aquifer recharge water source is abundant and its double aqueous medium quality，the water dynamic characteristics of obvious lag effect are shown. The hydro-geological parameters were corrected by the Boulton model，which was more close to the actual law of groundwater movement in the area through the field test. The research results in this paper are preliminarily revealed that in the coal rich zone of Turpan-Hami Basin，the particularity of Jurassic aquifer structure and groundwater dynamic field were caused by the differences of sedimentary environment and geological lithologies. [ABSTRACT FROM AUTHOR]

Xinjiang region has abundant Jurassic coal resources，but its exploration and developing degree are much lower，so one systematic research on its coalfield structural distribution pattern and structural styles is necessary. Based on the tectonism dynamic characteristics of main coal basin，through the analysis and research on years of regional geology and coalfield exploration data，this paper divided the coal-controlled tectonic in Xinjiang region into four structural patterns：Compression，Extension，Torsion and Invertion. Based on this division，also according to the geometric and kinematic features of coal-controlled structural association，this paper divided the Xinjiang coal-controlled structure further into six subgroups and 18 patterns，in which，the Imbricated Thrust Structure，Nappe Detachment Structure，Fold Structure and Strike Slip Structure have main control actions on coal measures，seam preserving status and mining geological conditions. [ABSTRACT FROM AUTHOR]