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In response to the challenging task of accurately identifying the main hazard-causing layer of overlying strata in the coal mine surface hydraulic fracturing construction, this study focuses on the industrial test of ground hydraulic fracturing at the 401102 working face of the Mengcun Coal Mine. The research is conducted using the methods of theoretical analysis, microseismic monitoring, and on-site investigation to reveal the dynamic disaster mechanism of mine earthquakes and rock bursts induced by the movement of thick and hard overlying strata in the coal mines. The relationship between the movement characteristics of thick and hard overlying strata based on a three-zone structure loading model of overlying strata and induced dynamic disasters is analyzed, and a prediction model for mining seismic energy and an estimation model for equivalent additional stress in mining areas based on the movement state of key layers are established. A coal mine identification technology for the main hazard-causing layer of overlying strata is proposed based on the K-means clustering algorithm and the elbow rule. The construction layer for hydraulic fracturing is determined, and an industrial test is carried out on-site. The effectiveness is verified based on the microseismic monitoring data and theoretical analysis results, leading to the following conclusions. In the Mengcun Coal Mine’s 401102 working face, both the key stratum responsible for rock bursts and mine seismic activities can be traced to the R9 key stratum of the Anding Group, situated 66 meters away from the coal seam. The primary fracturing movement of this critical stratum R9 imparts an equivalent supplementary disturbance stress value of 7.23 MPa, with the seismic energy liberated by this initial rupture motion quantifying to 6.08×105 J, thereby indicating a pronounced susceptibility towards catastrophic occurrences. After fracturing the key layer which induces mining earthquakes and rock bursts, the theoretical value of the mine earthquake energy is reduced by 94%, and the theoretical value of the equivalent disturbance stress of the working face is reduced by 76%. High-energy microseismic events above the working face with an energy of 5×103 J show a noticeable upward trend, with an upward movement of approximately 15 m. The frequency ratio of microseismic events with an energy level of 103 J or higher significantly decreases from 60.39% to 17.89%, and the maximum microseismic event energy decreases from 6.65×105 J to 9.75×103 J. The proportion of microseismic events with an energy level of 102 J and below significantly increases from 39.61% to 82.11%.

Abstract Rockburst, coal bump, and mine earthquake are the most important dynamic disaster phenomena in deep mining. This paper summarizes the differences and connections between rockburst, coal bumps and mine earthquakes in terms of definition, mechanism, phenomenon, evaluation index, etc. The definition and evolution progress of the three disaster categories are summarized, as well as the monitoring, early warning, and prevention measures are also presented. Firstly, by combining theoretical research with specific technologies and engineering field cases, the main categories and failure mechanisms of rockburst, coal bumps and mine earthquakes are introduced. Then, the evaluation indexes of coal bump and mine earthquake are summarized, and a new evaluation index of rockburst is given. Finally, the characteristics of monitoring, early warning technologies and prevention methods of rockburst, coal bumps, and mine earthquakes are discussed in technology and application. At last, the future directions of rockburst, coal bump and mine earthquake are put forward.

Mines with thick and hard roof face high risks of mine seismic activities and mine pressure during mining, which easily leads to dynamic disasters in mines. To pre-control and prevent such risks, it is necessary to pre-control the thick and hard roof of the mine. By field investigation, engineering analogy, theoretical analysis, laboratory test and numerical simulation, the occurrence characteristics of mine strata, potential mine seismic risk, fracturing of thick and hard roof and the mechanism of ground fracturing pre-control mine seismic risk are studied. The theoretical analysis shows that the mine with thick and hard roof not only has the mine seismic risk induced by the first breakage of the low and high thick and hard roof of a single panel, but also has the risk of aggravating the mine seismic event induced by the high thick and hard roof with the increase of the mining void of the mine. The analogy of engineering cases with similar conditions in Inner Mongolia and Shaanxi shows that mines with thick and hard roof occurrence conditions and mining conditions have the possibility of high mine seismic risk since the second panel is mined. Through the fracturing test of thick and hard roof, the rock brittleness coefficient is 59%~143%, and the average brittle mineral content is about 68%. The comprehensive results show that the fracturing characteristics of the thick and hard roof of the mine are better. The simulation comparison analysis shows that after the pre-splitting of the thick and hard roof, the concentration degree of the front abutment pressure and the front influence distance of the working face are obviously reduced. Based on various research results of thick and hard roof, the mine seismic risk pre-control technology using local ground fracturing pressure relief method is put forward, that is, fracturing is carried out by ‘L’ type drilling on the ground to thick and hard roof to reduce the integrity and compactness of thick and hard roof. The engineering application shows that in the fractured section, the highest frequency of microseismic events in the underground section is reduced by 52.2%, and the maximum energy release of microseismic events in the section is reduced by 56%. This shows that the ground fracturing pre-control technology of thick and hard roof successfully reduces the mine seismic risk and ensures the safe and smooth extraction of panels.

In the Ordos mining area of North China, the Jurassic coal seam is commonly overlain by extremely thick cretaceous sandstone strata. Based on the seismic displacement field and relative moment tensor inversion method, this paper investigates the mine earthquake mechanism and roof fracture characteristics of coal seams under extremely thick strata. In this study, by using seismic source groups as units and microseismic stations as objects, the source mechanism of mine earthquakes is inverted by constructing an inversion matrix, which greatly improves the inversion efficiency and accuracy. The focal mechanism of large-energy mine earthquakes located in solid coal section and goaf section under extremely thick strata is calculated. The characteristics of roof fracture evolution and the influence of vibration wave radiation are quantitatively analyzed. The results show that the extremely thick strata of Cretaceous goaf start to break when the panel below retreats along goaf. During this period, the surface subsidence increases rapidly, and the significant mine earthquakes with energy above 100 kJ begin to occur, and the mine earthquake distribution is more concentrative than that in the solid coal stage. Most of the large-energy mine earthquakes are located behind the goaf, which is closely related to the breakage and slide of the thick roof. Roof tension rupture accounts for more than 85% of the mine earthquakes. During mining along goaf, the seismic sources tend to expand upward, and more shear slip ruptures are presented compared with that in the solid coal mining stage. The strike of the fracture surface has a similar direction or an angle of “X” with the advancing direction. However, compared with that in the solid coal stage, the angle of “X” during mining along goaf increases from 30° to 45°. For the source rupture surface, the dip angle of between 0°−30° accounts for about 50% of the total. The failure type of roof is dominated by horizontal separation tension and roof rotation compression. The generated P waves mostly propagate to the goaf below, which causes a minor influence on the mining face. Only a small part of the P waves propagate to the surrounding working face, which may pose a great impact on the working face. The prevention and control strategy on the extremely-thick-strata type mine earthquakes can be conducted by weakening the integrity of thick strata and making thick strata break in tiers, aiming to reduce the rockburst risks to the working face induced by the breakage of the whole thick strata.

Rock mass dynamics disasters caused by excavations and mining occur frequently in deep mines. In order to establish a theoretical system and control technologies for such disasters, we first classify and define dynamic disasters, such as rock bursts, coal bursts, mine pressure bumps, and mine earthquakes. According to the occurrence mechanism of different types of dynamic disasters, we establish a compensation control theory based on excavation and mining effects. On the basis, we propose three key technologies: high prestress compensation technology for the roadway, pressure relief technology using directional roof cutting, and the goaf filling technology using broken rock dilation. These three technologies constitute the compensation control method for dynamic disasters in deep mines. Finally, this method was successfully applied in a deep coal mine with high stress, with monitored results suggesting its rationality. This work provides a new concept and control method for the prevention of rock dynamic disasters in deep mines.

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According to the present situation of prevention and control of coal mine rock burst in China, several key problems in the prevention and control system of coal mine rock burst are discussed, and the following main conclusions are obtained: from the perspective of disaster control, rock burst and mine earthquake and their relationship are defined, and 32 types of rock burst and 5 types of mine earthquake are put forward through the classification and combination of main force source and coal seam-surrounding rock structure, and it is clear that the goal of rock burst is to eliminate disasters, while mine earthquake needs to be treated according to the degree of disaster; Four impact risk evaluation indexes, namely, foundation stress impact index, additional stress impact index, impact tendency impact index and support strength impact index, are quantified, and a multi-parameter coupling evaluation method of impact risk including stress condition, impact tendency condition and support condition is designed. This paper probes into the monitoring and early warning mechanism of three-level impact hazards in vibration field, stress field and displacement field, puts forward an early warning mechanism combining single-parameter special warning with multi-parameter conventional warning, and designs a joint monitoring method for the excavation-affected area, mining-affected area and non-excavation-affected area. According to the requirements of reducing the impact risk of various factors in multiple evaluation indexes, the prevention and control routes of rock burst with low stress, low disturbance, low inclination and strong support are put forward, and the combination technology of local pressure relief and risk relief measures based on stress and surrounding rock structure classification is designed. In view of the dynamic disasters caused by underground rock burst and ground vibration caused by mine earthquake, the governance levels of such disasters are divided into three levels: prevention and control, symptomatic control and source control, and a multi-level prevention and control technology system of source shock absorption, classified disaster treatment, pressure relief and earthquake resistance is designed.

Fracture of high-level extra thick and hard roof (ETHR) above the coal seam is the main reason for the frequent occurrence of mine dynamic disasters such as mine earthquake and rock burst. In order to address this problem, the ground fracturing technology was proposed in this paper to presplit the high-level roof. The FLAC numerical model was established to study the dynamic response of the ETHR before and after fracturing. The simulation results show that: The existence of hydraulic fracture can effectively reduce the first breaking span of ETHR, and slow down the stress and elastic deformation energy concentration of coal and rock mass on both sides of goaf. In order to ensure the economical and effective opening of prefabricated cracks, the comprehensive influence of tensile stress zone and induced stress between cracks should be fully considered in the design of crack spacing. Finally, the field test of hydraulic fracturing was carried out in 63up06 working face in Dongtan coal mine in China. The results of microseismic monitoring showed that there were only 4 strong mine earthquake events of magnitude 2.0 that happened in the first 400 m of excavation, compared with the adjacent working face, the number of large energy mining earthquake events decreased significantly. It showed that the ground fracturing effectively controlled the high and thick strata and verified the feasibility of the ground fracturing technology. The research results can provide some guidance for the treatment of mine earthquake and rock burst in similar working face. [ABSTRACT FROM AUTHOR]

To study the monitoring and early warning ability of DInSAR and SBAS InSAR for mine earthquake collapse in goaf area, this paper uses the two InSAR techniques to process the 11 scene C-band Sentinel-1A SAR images before and after the mine earthquake to obtain the mine deformation by taking the coal mine in Shandong Province where mine earthquake recently occurred in goaf area as the research area. The result shows that both InSAR technologies detected abnormal surface deformation in the mining area, which converted from relatively stable deformation process to obvious subsidence. DInSAR and SBAS InSAR can be used to detect long-term surface deformation process and abnormal deformation in the goaf, and provide a reference for the analysis of the surface stability of the goaf area and early warning of mine earthquakes.

Mine earthquakes are serious disasters in coal mines, especially in extremely thick hard strata. This study investigates the occurrence mechanism of fracture-type mine earthquakes in thick hard strata. Hydraulic fracturing by ground vertical well was used for shock absorption. Dongtan coal mine was taken as a case study. Field investigation, theoretical analysis, industrial tests, and field monitoring were used for revealing the mechanism. First, the mechanical model of extremely thick, hard strata under horizontal concentrated stress was established. The fracture step equation and energy release equation of extremely thick hard rock were derived by semi-inverse solution and variational method. Then, the mechanical model of extremely thick hard rock after hydraulic fracturing by ground vertical well was established. The relationship between the spacing of the ground vertical well and the maximum magnitude of mine earthquakes was deduced. The fracturing well in the 6306 working face was designed for controlling the maximum mine earthquake magnitude. Results show that the increases in the breaking distance of the thick hard rock layer led to an increase in the released energy during the fracture, and an enhancement of the magnitude of the mine earthquake. By applying hydraulic fracturing technology using the ground vertical shaft, the occurrence frequency and total energy of mine earthquakes above 1.5 ML in the 6306 working face decreased by 54.55% and 81.22% than that in 6304 working face, and reduced by 70% and 84.98% than that in 6305 working face. Hydraulic fracturing technology by ground vertical well can significantly reduce the frequency of fracture-type and the total energy of mine earthquakes in extremely thick and hard strata. However, it can not prevent and control the occurrence of back-transition mine earthquakes and slip-type mine earthquakes. The obtained results can provide a basis for the fracture-type mine earthquake mechanism and fracturing shock absorption technology in coal mines with super-thick hard strata. [ABSTRACT FROM AUTHOR]

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With the increase in mining depth and the deterioration of mining conditions, thick and hard overburden movement frequently induces mine earthquakes and rock bursts. Some mines are expected to prevent and control super thick hard rock mine earthquakes through vertical ground well water fracturing technology. However, the dynamic underground disaster appears more intense. Taking the '11.30' mine earthquake in a mine in Shandong Province as the engineering background, the dynamic disaster mechanism of an extraordinarily thick and hard roof induced by hydraulic fracturing of vertical wells on the ground was studied utilizing field investigation, accident case analysis, similar material simulation test, and theoretical analysis. The main conclusions are as follows: (1) After hydraulic fracturing vertical wells on the ground, the movement mode of thick and hard roofs changed from layer-by-layer to overall sliding movement; (2) The influence range of the advanced abutment pressure of the working face is reduced by the hydraulic fracturing of the vertical shaft, and the peak value of the advanced abutment pressure increases. Furthermore, the advanced abutment pressure's peak is far from the coal wall; (3) The hydraulic fracturing technology of cross-arranged vertical surface deep and shallow wells and the hydraulic fracturing technology of cross-perforated surface multi-branch horizontal wells are proposed to avoid the dynamic disaster of overall sliding movement of an extremely thick hard roof induced by surface hydraulic fracturing. Therefore, these research results provide significance for preventing and controlling mine earthquakes and rock bursts in super thick hard roof mines. [ABSTRACT FROM AUTHOR]

Under the background of the intelligent construction of a coal mine, how to efficiently extract effective information from the massive monitoring data of mine earthquakes, and improve prediction accuracy, is a research hotspot in the field of coal mine safety production. In view of this problem, more and more machine learning methods are being applied to the prediction on mine earthquakes. Considering that clustering analysis can enhance the correlation between microseism data, we propose a method whose main idea is to cluster microseism data before establishing the prediction model, and then train the model, so as to improve prediction accuracy. Specifically, microseism events on a working face are divided into clusters in advance by the Spatial Temporal-DBSCAN(ST-DBSCAN) algorithm, then a prediction model is established with Support Vector Regression (SVR) to predict the occurrence location and daily frequency of high-energy mine earthquake events. A set of engineering experiments were conducted in H Coal Mine, and the results show that the spatial-temporal clustering analysis of microseism events can indeed improve the prediction accuracy of machine learning methods on mine earthquakes. [ABSTRACT FROM AUTHOR]

Accurate identification of natural and mine earthquakes in mining areas is of great significance to the construction of secondary disaster warning networks. Based on 490 records of natural and mine earthquakes in the Hegang area from 2006 to 2017, this paper compares and analyzes the ground motion characteristics of the research samples (150 earthquake records and 200 mine earthquake records) and selects the key identification parameters of dominant frequency, Pm/Tc, and Sm/Tc. The correct identification rate of the test samples (60 seismic records and 80 mine earthquake records) is 95.7%, 91.4%, and 93.6%, respectively, and the actual threat rate is 90.8%, 83.3%, and 86.3%, respectively. Finally, based on the selected key identification parameters, a "three-parameter comprehensive gradient discriminant method" is proposed. The correct identification rate and actual threat rate are 99.3% and 98.4%, respectively, which can basically accurately identify natural and mine earthquakes. It provides a certain method and theoretical support for the mining area vibration identification method, safety production, and disaster warning. [ABSTRACT FROM AUTHOR]

In summer, the rainfall in Fushun occurs frequently and lasts for a long time. If there is a mine earthquake, the slope is very easy to be unstable and destroyed. The limit equilibrium method combined with the seepage field is used to analyze the slope stability, so that we can analyze the impact of mine earthquakes in the rainy season on the Fushun West Open-pit Mine.The results show that with the same rainfall intensity and the longer duration, the pore water pressure contour is denser, and the more closed areas of the contour are, the lower the safety factor of the slope is. At the same duration, the greater the rainfall intensity, the faster the pore water pressure contour map changes; Rainfall is the same, the smaller the rainfall intensity, the greater the range of rainfall infiltration; After adding the horizontal mine earthquake load factor, as the mine earthquake intensity increases, the slope safety factor decreases. There is a rainfall critical value for slope rainfall. When the rainfall does not reach the critical value, the safety factor of the slope decreases slowly, and when it reaches the critical value, the safety factor decreases rapidly. Rainfall and mine earthquake have a great impact on the safety of the slope, so the slope should be reinforced in advance.

In the process of deep mining, the prevention and control of rock bursts, mine earthquakes, and other disasters are common problems. The stress of earth tides and its periodic actions should trigger mine earthquakes when the rock masses are in a critical state of rupture. In this study, the Yanbei coal mine was taken as the research background to explore the triggering effect of solid tides on mine earthquakes occurring in the floor. The relationship between the diurnal tidal stress phase and mine earthquakes was studied by statistically analyzing the mine earthquake frequency, and the triggering mechanism was also preliminarily discussed. It was found that the solid tide plays a significant role of trigger action in the occurrence of rock burst of the floor type. For different levels of mine earthquakes, the tidal stress triggering effect is different, but the overall trend is close. Compared with the components of tidal stress, vertical stress, north-south stress, and shear stress, rock burst occurred more at the stage close to 0° and ±180°. For different types of mine earthquakes, the triggered mechanics function of tidal stress is different. Mine earthquakes on the floor mainly include two kinds (the gravity control type and horizontal stress control type). The former easily occurs during the tidal stress vertical component of the maximum, while the latter easily occurs when the two horizontal components of the maximum are combined. The frequency of the former is larger than that of the latter. The results show that the floor seismic activity is correlated with the solid tidal activity of the earth’s crust, which provides a new idea for understanding the mechanism and trigger conditions of mine earthquakes.

Under the background of the intelligent construction of a coal mine, how to efficiently extract effective information from the massive monitoring data of mine earthquakes, and improve prediction accuracy, is a research hotspot in the field of coal mine safety production. In view of this problem, more and more machine learning methods are being applied to the prediction on mine earthquakes. Considering that clustering analysis can enhance the correlation between microseism data, we propose a method whose main idea is to cluster microseism data before establishing the prediction model, and then train the model, so as to improve prediction accuracy. Specifically, microseism events on a working face are divided into clusters in advance by the Spatial Temporal-DBSCAN(ST-DBSCAN) algorithm, then a prediction model is established with Support Vector Regression (SVR) to predict the occurrence location and daily frequency of high-energy mine earthquake events. A set of engineering experiments were conducted in H Coal Mine, and the results show that the spatial-temporal clustering analysis of microseism events can indeed improve the prediction accuracy of machine learning methods on mine earthquakes.

Copyright of Chinese Journal of Geological Hazard & Control is the property of China Institute of Geological Environmental Monitoring (CIGEM) Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

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

In order to explore the causes of unusual gas emission, coal and gas outbursts in coal mines with outburst elimination and traditional safe mining conditions during underground deep mining process, the existence of low gas catastrophes in gas containing coal seams is confirmed by literature review and field investigation. Through field gas monitoring, microseismic observation and empirical analysis, the process and cause of low gas catastrophes in the outburst elimination of coal seams are recognized. Physical experiment and theoretical analysis on the gas solid coupling of big coal samples with low gas, the evolution path of stress strain seepage field at low pressure and the physical catastrophe mechanism of gas solid coupling for pressure bearing coal samples are studied. There are many reports that the low gas catastrophes in the coal seams can happen during mining process in deep coal mines with outburst elimination and traditional safe mining conditions. Field observation and analysis reveal the model of low gas catastrophes in coal seam under the action of roof weighting, roof weighting breaking impact and floor weighting impact. The boundary conditions of mining and excavation face are simulated, the catastrophic process at low gas observed in the gas solid coupling physical experiments at 0.4 MPa pressure involves three steps: elastic compaction gas constant velocity and deceleration steady seepage, plastic dilatation gas growth unsteady seepage, and rupture instability gas unsteady seepage catastrophe. The conclusions are that many secondary fissures are formed in pressure stable area after taking outburst prevention measures, which is beneficial for improving the de sorption performance of gas. It could be the initial region of low gas pressure catastrophe, along with plenty of gas gathered. A “three zone” dynamic evolution theory of gas migration in front of mining induced region of coal seams is given, and its characterization is clarified corresponding to the 40% extreme elasticity, and the ultimate failure load according to the change of stress value. In a word, the “three zone” dynamic evolution theory of gas migration in front of mining induced region of coal seams is the main reason of catastrophes with low pressure gas. The catastrophic process and conditions for ordinary gas emission, unusual gas emission with low gas, unusual gas emission with high gas, and catastrophes are given. In addition, low gas catastrophes in gas containing coal seams can be initiated in advance under the dynamic pressure impact of the superposition of the roof and floor breakage. [ABSTRACT FROM AUTHOR]

In the western part of China, mine disasters such as support failure, surface stepped subsidence and mine earthquake, are prone to occur when lower coal seam is extracted which is closely beneath the coal pillars left after room-and-pillar mining with shallow overburden. In this paper, physical modelling and numerical simulation method were adopted to investigate the dynamic instability process of upper coal pillar group and the mechanism of support failure under the influence of lower coal seam mining. According to the measured statistics in some mines after coal mining of Yuyang District, only when the proportion of elastic core area of the coal pillars is greater than 31% can the room coal pillars keep long-term stability. The simulation result after mining lower coal seams shows that the failure form and instability sequence of the upper coal pillars have close relations with the positions relative to the lower coal seam working face. The damage and instability of room coal pillar occur in the positions of open-off cut, working face, and the middle of goaf successively. Furthermore, the coal pillars in the open-off cut and working face mostly show horizontal shear failure, while the coal pillars in the middle of the goaf show vertical fracturing damage. According to the numerical simulation results of Shigetai Coal Mine, the peak abutment pressure of coal pillar in upper 2-2 coal seam increases from in-situ stress 2. 8 MPa to 12 MPa after coal mining with the stress concentration factor at 4. 28. After the lower 3-1 coal seam working face mined, the peak abutment pressure of the retained pillar in upper 2-2 coal seam continually increases to 30 MPa with the stress concentration factor up to 10. 71. The open-off cut side of the lower coal seam working face showed uneven horizontally bearing with the coal pillar directly above the lower coal seam working face and the influence of horizontal tensile deformation are the main reasons for the diagonal failure mode of the boundary coal pillars. After the instability of two sides coal pillars, the roof instantaneously occur overall shear breakage, causing mine earthquake, and multi-layered strata in the roof settled suddenly in the form of "rigid body motion"and hit against the floor, leading to the collapse of the room coal pillars in the middle of goaf. At the same time, the huge impact force further leads to the full cutting of the strata between the upper and lower coal seams, which results in the roof cutting and support failure in the lower coal seam working face. It was found in the experiment that there was only about 0. 45 seconds from the failure of the first coal pillar in the overlying coal pillar group to the overall unstable movement and the final stability, among them, the full cutting of the strata between the upper and lower coal seams only took about 0. 05 seconds. [ABSTRACT FROM AUTHOR]

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

In order to understand the mechanism and prevention of rockburst in Huating mine, the rupture mechanism of rockburst was inversed, using focal mechanism solution method. Combining with in-situ stress measurement, microseismic monitoring, field investigation, mining analysis and theoretical analysis, the focal mechanism solution method was proved to be reliable, and the appropriate control strategies would be made after analyzing the causes of rockburst. It was concluded that the focal mechanism solution method was effective for mining rupture mechanism inversion. The frequent rockburst in Huating mine was mainly caused by great horizontal stress, the large angle of intersection between maximum principal stress direction and roadway trend, the large unsupported roof of thick sandstone, and the large thickness and strong burst trend of bottom coal. There were several ways to prevent mine rockburst. During coal face design, it should be avoided that the maximum principal stress direction intersected roadway trend with a big angle. Mining lower slice with good impact resistance, relieved vertical mining stress by roof presplitting,roadway drilling and cutting off the floor, were also the major solutions for the prevention of rockburst. [ABSTRACT FROM AUTHOR]

Movement and deformation of underground rock include vertical dislocation and horizontal deformation, and the energy released by mine earthquake can be calculated basing on deformation energy. So put forwards the prediction for degree and spread of mine earthquake according to the underground rock’s movement and deformation. The actual number of times and spread of mine earthquake on site were greatly identical to the prediction. The practice proves the possibility of prediction for mine earthquake basing on the analysis of underground rock’s movement and deformation, and sets up new approach of mine earthquake prediction. [ABSTRACT FROM AUTHOR]