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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]

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]

The theory and method of mining subsidence monitoring based on D-InSAR(differential interferometric synthetic aperture radar) technology is a hot topic in the current field of mine deformation monitoring. At present, three-dimensional monitoring model of mining subsidence has been constructed successfully by some scholars through integrating single line of sight to D-InSAR technology and mining subsidence law. However, the model is only suitable for the researches on mining subsidence of horizontal coal seam rather than inclined coal seam. In view of the above defects，according to the relationship between deformation of line of sight monitored by D-InSAR and three-dimensional deformation, considering the surface subsidence law of inclined coal seam mining, the surface subsidence monitoring method for inclined coal seam based on single line of sight to D-InSAR technology is proposed. The simulation experiment shows that the absolute relative error of the subsidence monitoring method is less than 9. 53%, with an average of 1. 31%. The absolute relative error of the horizontal movement monitoring along North-South (SN) and East-West (EW) is less than 9. 78%，with an ave-rage of 3. 71%, which meets the mining subsidence monitoring accuracy requirements. The surface movement and deformation caused by the mining of the 9310 working face of Nantun coal mine in yanzhou mining area, Shandong province China during 2012-01-27 - 2012-02-07 are successfully monitored by this method in this paper [ABSTRACT FROM AUTHOR]

The protection and utilization of groundwater resources in coal mining process is the prerequisite and necessary condition for realizing green mining at the ecological fragile mining area in western China. Among them, the extensive application of water-preserved mining and underground reservoir technology provides the possibility for solving the problem of coal-water co-production. In this paper, with the background that the stability of the coal and rock boundary of underground reservoir changed under the conditions of repeated immersion in water, the sandy mudstone of the No.3-1 coal seam roof of Wulanmulun Mine was investigated. The natural water absorption law of the sample was obtained by non-destructive water immersion test, and the water immersion time of the sample water content reaching saturation state was obtained. According to the immersion time, the sample was dried-saturated and repeatedly immersed in water. It was found that the water content increased exponentially with the number of immersion, whereas the shear strength and the number of water immersion in the sample decreased exponentially. The cohesive force decreased with the increase of the number of immersion times, while the internal friction angle increased first and then decreased, indicating that the uniformity of the material, and the shape of the fracture surface and the shape, size and direction of the fracture caused the internal friction angle to increase. The cycle immersion later was the dominant factor to make the internal friction angle decrease. Based on the relationship between cohesion, internal friction angle and number of dry-saturated cycles, the Mohr-Coulomb criterion was established based on the number of dry-saturated cycles. The acoustic emission counting curve had a strong correspondence with the shear stress curve. The acoustic emission event increased significantly at the moment of sample failure, corresponding to the obvious rising phase of the cumulative acoustic emission counting curve. The sample mainly had a low RA value during the failure process, and the failure time corresponded to a high RA value, i.e. , the common type of crack in the failure process of the specimen was tensile crack, and the moment of failure corresponded to the obvious shear crack. These results show that the strength of coal and rock pillars in the groundwater reservoir boundary changed significantly under the action of water immersion-water loss during the impoundment-pumping process in the groundwater reservoir. It is suggested that the weakening effect of water on the strength of boundary coal and rock pillars should be considered when constructing the underground reservoir. [ABSTRACT FROM AUTHOR]

Water resources destruction and geological environment changes caused by mining in ecologically fragile areas of western China have seriously restricted the sustainable development of economy, society and environment in mining areas. Through reviewing the research progress of water-preserved coal mining and carrying capacity of geological environment in coal mining areas, and combining with the current situation of geological environment in western China rich in coal and short of water, the research framework of carrying capacity of geological environment based on the concept of water-preserved coal mining is proposed. It is considered that the function mechanism of "coal mining activity-water resource destruction-geological environment effect"should be systematically analyzed by combining the concept of water-preserved coal mining with the theory of carrying capacity of geological environment. The methods of attribute analysis, ecological demand analysis, numerical analysis and catastrophe theory should be used in studying the carrying capacity of geological environment. In particular, the quantitative method, comprehensive evaluation method and the classification method of carrying status and carrying capacity of geological environment should be investigated. By means of simulation experiment, the relationship data between the geological environment and the critical value of mining intensity under the carrying capacity of typical coal mine area are obtained. Then the technological method of coal mining under water-containing for controlling and alleviating the geological environment problems in coal mine area is extracted to determine the reasonable mining intensity and scale. On the basis of the research of carrying capacity, this paper put forward the collaborative monitoring method for the influencing factors of carrying capacity of geological environment, and the criterion of bearing capacity early warning grade of carrying capacity. The connotation and basic research ideas of geological environmental carrying capacity based on the concept of water-preserved coal mining will enrich the scientific connotation of water-preserved coal mining and geological environmental carrying capacity, and provide a theoretical and technical support for the coordinated development of coal resources and water resources protection in the fragile ecological environment areas of western China. [ABSTRACT FROM AUTHOR]

The exploitation of underground coal resources can easily lead to the loss of precious shallow water resources, which leads to the death of surface vegetation and the imbalance of ecosystem. To protect the shallow water resources( river, lake and diving of quaternary sand aquifer), which maintains the ecological environment of the western mining area, especially to protect the underground diving( ecological) water level, the concept of water conservation mining in short-distance coal seams was put forward based on the previous theoretical achievements of water conservation mining in shallow single coal seam and the experience of rock control engineering. The concept integrated the protection of ecological water level, and the prevention and control of water inrush. In order to achieve an efficient water conservation mining under the mining conditions of short-distance coal seams and extremely short-distance shallow water resources, this paper studied the technical problems, such as the collaborative control of strata water-conducting fractures in the disturbed area of repeated mining, the low-damage control of ultra-thin barrier layers and the monitoring and warning of water inrush( outburst) on mining surface. The study presented the long wall water conservation mining method, the water conservation mining under continuous mining and filling with wall system and the infrared monitoring and warning methods for water inrush in working face to realize the safe and efficient mining. More specifically, the methods included the strata control of short-distance coal seams, the calculation of the height of water-conduct fractures, the deformation calculation of aquicludes, the infrared radiation theories of loaded coal and rock, the control of water diversion fractures in the disturbed area of repeated mining, the filling body actively connected to the roof and the rapid operation technology among mining, supporting and transportation. Meanwhile, the weak areas of water conservation mining were determined. Based on water resource protection, the optimized working face layout of shallow buried and short-distance coal seams, mining method allocation and water resource movement monitoring, an efficient mining theory was formed. The achievements have been achieved in the practice of water conservation mining in north Shaanxi and north China, which provides supports for green mining in China. [ABSTRACT FROM AUTHOR]

Coal bump often occurs in the mining process between two adjacent mines under the control of large geological bodies. In order to study the coal bump mechanism between adjacent working faces of two adjacent coal mines under the condition of large fault and huge thick overburden conglomerate, this paper investigates the 23070 working face at Yuejin coal mine and the 21220 working face at Changcun coal mine in China. The analyses of monitoring data are carried out on the characteristics of coal bump behavior, microseismic spatio-temporal evolution and microseismic energy. Furthermore, the theoretical analysis and numerical simulation of stress distribution of overburden structure during the mining process of two working faces are conducted. The results show that the activation of F16 thrust fault and overall control of massive conglomerates in Yima mining area provide the stress conditions for coal bump. During the mining process of two mines’ adjacent working faces, the "asymmetric T-shaped"structure is formed between the rock beamabove the goaf and coal-rock pillar between two mines. The coal bump around the 21220 working face leads to the stress transfer onto the two mines’ pillar and the 23070 working face, which induces the coal bump around the 23070 working face. Mining disturbance between two mines leads to stress transfer and induces rock burst, which is closely related to the initial bump intensity and mining length of later working face. Finally, based on theory and engineering monitoring, a coal bump controlling technique with chain-weakening and consumption-increasing between two coal mines is put forward, which regards the weakening of the structural chain of high stress transfer as core. The results provide a theoretical basis for the study on the mechanism and control of coal bump between two adjacent working faces in two adjacent mines. [ABSTRACT FROM AUTHOR]

Carrying out mine environmental research is a concrete action to build a "beautiful China", which can turn abandoned mines into mountains with clear waters and green trees. The previous exploitation of mineral resources was at the expense of human living environment, resulting in irreparable waste of resources and destruction of ecological environment, which brought serious mine environmental problems. At present, China is faced with outstanding mine environmental problems, but the restoration progress of mine environment is relatively slow. In order to solve the mine environmental problems caused by the exploitation of mineral resources scientifically, the idea of systems engineering is adopted, and the paper means to address the mine environmental problems from the following nine aspects: classification, investigation, evaluation and prediction, restoring techniques and modes, evaluation of land suitability, monitoring and early warning, information system research and development, regulations and standards, and mine environmental management. The classification scheme of mine environmental problems and the effect characteristics of each type are put forward; and in order to standardize mine environment investigation and data collection, the technical methods and standards of field in situ investigation are established; in order to grasp the present situation of mine environment and predict the future, the methods and models for mine environment evaluation and environmental predictions for different development schemes are put forward; due to the systematic attribute of mine environment, the research on environmental problems, remediation targets, remediation technologies and remediation model has been carried out, and the restoration and treatment model of mine environment has been established; from the perspective of the restoration and reuse of mine land resources, the theory and method of land suitability evaluation after restoration and treatment are constructed; and the monitoring and early warning technology of mine environment is developed for real time monitoring, analyzing the changing trend and early warning the emergencies; in order to visually display the achievements of mine environmental remediation and to share the experiences and lessons of restoration and management, a mine environmental information management system based on cloud platform, big data and other modern information technologies is developed; the laws, regulations and standards about mine environment at home and abroad are collated, compared and analyzed; and the responsibilities of the government and enterprises in the management of mine environment are expounded. Finally, the future development of mine environment research are prospected from the aspects of elimination the negative impact on ecological environment, exploitation the positive-effect resources of closed-pit mines, economic construction and transformation of mining cities, prevention theory and methods in deep mining mines, ecological environment of underground mines, theory and technology for public safety prevention and control, setting up of mine environment platform with big data and artificial intelligence. [ABSTRACT FROM AUTHOR]