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Slip and instability of coal-rock parting-coal structure (CRCS) subjected to excavation disturbance can easily induce coal-rock dynamic phenomena in deep coal mines. In this paper, the failure characteristics and influencing factors of CRCS slip and instability were investigated by theoretical analysis, numerical simulations, and field observations. The following main results are addressed: (1) the slip and instability of CRCS induced by excavation are due to stress release, and the damage of the rock parting is partitioned into three parts: shear failure zone, slipping zone, and splitting failure zone from inside to outside with slip; (2) the slip and instability process of CRCS is accompanied by initiation, expansion, and intersection of shear and tensile cracks. The development of the cracks is dominated by shear behaviour, while the tensile crack is the main factor affecting fracture and instability of CRCS; and (3) slip and instability of CRCS are characterized by stick-slip first and then stable slip, accompanied with high P-wave velocity and rockburst danger coefficient based on microseismic tomography.

Taking coal under hydro-mechanical coupling as the research object, the discrete element software PFC3D (particle flow code) was used to analyze the relationships among the force, acoustic emission (AE), and energy during coal fracture. Based on the moment tensor (MT) inversion, we revealed the AE event distribution and source type during crack initiation and propagation until the final failure of coal. Meanwhile, we examined the relationships among the stress, number and type of cracks, magnitude, KE, and b value of AE under different water and confining pressures. The results show that the numerical simulation can effectively determine the microscopic damage mechanism of coal under different conditions. Moreover, the rupture type of the numerical simulation is consistent with the field investigations, which verifies the rationality of the simulation. These research results can provide reference for safety production evaluation of water inrush mines.

Irregular coal pillars are often reserved in the upper coal seam in multiseam mining due to the limitation of geological conditions and mining methods. Diffused and transmitted stress in the pillars will form the stress concentrated areas in the lower coal seam and will increase the risk of rockburst. Based on the upper irregular pillars and fault encountered in the 7301 working face of the Zhaolou coal mine, this paper studies the evolution of stress and energy when the working face passed through the area affected by pillars. The adopted methods include numerical simulations and field monitoring. The change in stress concentration factor and stress gradient because of the mining activities in lower coal seam was analyzed by numerical simulation, indicating that the stress gradient reaches a peak when the working face is closed to the area under the edge and junction of pillars, which has the high risk of inducing rockburst. The sources’ location, variation rule of microseismic (MS) total energy and events, frequency spectrum distributions, and source parameters are discussed, respectively, based on the field monitoring data. The main conclusions were obtained as follows: (1) The total energy and event counts reach the peak when working face is close to the area under the edge and the junction of pillars. (2) The dominant frequency transfers from high frequency to low frequency, the stress drop reaches the peak value, the energy index decreases sharply, and the cumulative apparent volume increases sharply, which all are obvious precursory characteristics before rockburst.

The slip and instability mechanisms of coal‐rock parting‐coal structure (CRCS) under coupled dynamic and static loading were investigated using theoretical analysis and numerical simulations, and the fracture and instability processes were described by monitoring the displacement, strain, and acoustic emissions (AEs) of coal and rock parting blocks. Based on the parameters of dynamic load, three different effects on slip and instability characteristics of CRCS were presented, and the effect mechanisms of static stress, as well as amplitude and frequency of dynamic stress wave, were analyzed in detail. Finally, the direct effect on the slip and instability strength of CRCS and the frequency range of dynamic load for generating synchronous slip along two discontinuities sandwiched between coal and rock parting blocks were discussed. This work is relevant for early warning coal‐rock dynamic disasters that are triggered by the slip and fracture instability of CRCS under coupled dynamic and static loading in coal mines.

Based on experimental and in-situ tests, the propagation and attenuation rules of seismic wave in the intact and jointed rocks subjected to conventional triaxial loading condition were investigated, especially the influencing effects of joints and beddings on the attenuation. Meanwhile, the frequency-spectrum evolutions during the process of attenuation were analysed in detail. To verify the outcomes obtained from the laboratory, the attenuation characteristics of seismic wave generated by blasting in underground strata were tested, and the attenuation rules by the joints between strata was summarized. Finally, the seismic response of joints and beddings in rocks was revealed. This work put forward some references for early weakening and controlling coal-rock dynamic disasters triggered by seismic wave in coal mines based on the attenuation effect of artificial discontinuity such as joint and bedding.

The existence of parting in coal can contribute to unstable slip and shear failure, and even rockburst of mining faces and sidewalls. In this work, the rockburst triggered by the slip and fracture of coal–parting–coal structure (CPCS) discontinuities subjected to dynamic stress was visually investigated by numerical simulation, and the stress and displacement as well as the corresponding vibration characteristics surrounding the parting during the rockburst were comprehensively analyzed. Eventually, the rockburst triggering mechanism was summarized. As a field testimony for verifying the numerical results, the “11.20” rockburst in the first parting zone of the 1307 working face of the Zhaolou coal mine (ZCM) was investigated in detail by microseismic (MS) tomography. The following main conclusions were obtained: (1) rockburst may be triggered by the slip and fracture of a CPCS subjected to dynamic stress with a violent ejection of a large number of parting fragments at a high speed. The peak particle velocity (PPV) 10 m/s can be regarded as a critical vibration velocity for rockburst warning; (2) during rockburst, the vibration characteristics of different positions surrounding the parting are closely associated with the coal and rock failure caused by the slip and fracture of the parting; and (3) based on the clustering of many high-energy MS sources in the parting zone combined with a high P-wave velocity, velocity gradient, stress concentration and strain energy, it was fully verified that the “11.20” rockburst was triggered by the slip and fracture of the wedge-shaped parting. Additionally, the sudden and sharp rise of the fault total area (FTA) can be regarded as a precursory sign to warn rockburst. The in situ observations lend credence to the numerical simulations.

To reveal the mechanism and precursors of the “1.21” rockburst induced by hard roof fracturing in the No. 1 working face of the Junde coal mine (JCM), the inversions including P-wave velocity, velocity gradient, stress concentration and accumulated energy were elaborately conducted by seismic tomography, and the static high-stress concentration and dynamic stress transfer were vividly demonstrated. Simultaneously, the multi-parameter characteristics including microseism (MS), electromagnetic emission (EME) and acoustic emission (AE) before and after the rockburst were comprehensively investigated, and then the corresponding precursors were summarized. The main conclusions are as follows: (1) the intrinsic factor of the “1.21” rockburst is owing to the original static high stress concentration in tailentry ahead of the No. 1 working face, and the external factor is ascribed to the dynamic stress transfer and superimposition with energy input generated by roof fracturing; (2) before roof fracturing, the region where sources congregate shows higher velocity, velocity gradient and stress concentration, accompanied with energy accumulation. After fracturing, the region manifests abnormal low velocity. However, the surrounding and far-field rockburst destruction regions appear higher velocity due to dynamic stress transfer; and (3) an obvious transform from dominantly hybrid to dominantly low-frequency of MS events will occur as roofs experience micro-fissure initiation, propagation, convergence, and coalescence, and thus it is concluded that the gradual transform of MS dominant spectrum from high to low frequencies represents a precursor for warning roof fracturing. The findings may put forward a certain reference for warning the type of rockburst triggered by roof fracturing.

Fault slips and triggered rockbursts pose a significant threat to the safety of mining personnel and infrastructure in deep coal mines. Sudden and dynamic slip may occur along a pre-existing fault characterized by the presence of contact between two opposite faces. Such slips are capable of changing the balance of forces when mining activity is conducted in the area surrounding the fault at depth and are accompanied by energy release that has the potential to cause serious damage to roadways and working faces. The aim of the comprehensive investigation reported here was to elucidate the evolution of the stress field surrounding a fault due to mining activity in adjacent working faces, using Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) numerical simulations, especially variations the high shear stress area. We then proposed the mining-induced fault slip mechanism. The evolution rule of sources during fault slip could be clearly explained using field microseism (MS) monitoring data, and the correlation between source parameters (e.g., static stress drop, peak particle velocity, and displacement) and fault slip was established. Correspondingly, the multi-parameter precursors of a rockburst induced by the fault slip were analyzed and summarized in detail. This work provides a number of reference points to be used for the warning and controlling of rockbursts triggered by fault slip in coal mines.

Based on theoretical analysis and numerical simulations, the factors that influence the slip and fracture instability of coal-rock parting -coal structure (CRCS) were investigated. Stress, coefficient of friction and energy dissipation during slip and fracture instability were analysed individually. The macro- and microscopic mechanical behaviours, especially acoustic emission (AE) characteristics, were determined. According to the variations in stress, energy and b-value of AE events, the precursors of CRCS slip and fracture instability were summarized. Finally, the instability mechanism was proposed. This work is relevant for early warning coal-rock dynamic disasters that are triggered by slip and fracture instability of CRCS in coal mines.

Earthquake precursors are vitally important for warning and risk evaluation, but shedding light on them is a complex task for seismologists and geologists. We attempted to illuminate the precursory rules of fault failure by traditional biaxial-direction shear tests for a zigzag-type gouge with different size and arrangement of simulated faults manufactured from polymethyl methacrylate materials. Shear stress, acoustic emissions, and vibration signals were recorded and comparatively analyzed. Two important findings were obtained: (1) the linearly increasing trend of shear stress peaks generated by foreshocks may indicate the foreshock effect before a larger earthquake triggered by natural fault gouge failure; and (2) four kinds of earthquake precursors were discovered, and earthquake intensity and precursors may be dependent on the time of macro-fracture formation and the quantity of micro-fractures initiated before mainshock. The study contributes to interpreting earthquake shear-slip characteristics and may even help provide warnings of failure and instability.

During the past decade’s exploitation of coal seams in Muchengjian Mine in Jingxi Coalfield, there were nearly thirty rock burst events, which hindered the safe and efficient coal production. Two typical mining areas were selected for analysis where almost half of rock burst events occurred. The research was aimed at finding connections between the occurrence of rock bursts and geological characteristics. The temporal and spatial characteristics of rock bursts were described in detail, the geological characteristics were investigated carefully, and the possible reasons for rock bursts were analyzed. The details documented in these cases not only provide an essential reference value for understanding the development mechanism of rock bursts, but also provide a basis for selecting control measures and optimizing related technical parameters during tunneling or mining under complicated geological conditions.

In the underground coal gasification (UCG) process, a feasible method for the reduction of CO2 emissions is to capture the CO2 present in syngas and reinject it as one of the gasification agents, which is called CO2 recycling. In this process, CO2 partially replaces steam as a gasification agent, which is of particular importance in areas lacking sufficient water. To obtain a more accurate and generally applicable means of calculation, a modified equilibrium calculation method, which calculates UCG parameters in the presence of CO2 in the gasification agent over two stages and then merges the resulting data, has been established. In addition, a suitable method for establishing optimal gasification agent parameters is proposed. Corresponding MATLAB™ routines were then compiled and applied to UCG gasification agent parameters optimisation simulations using data of Ankou coal. Calculation results indicated that CO2 partially replaced steam, and that an increase in CO2 concentration in the gasification agent enhanced the reduction reaction between CO2 and hot coal. In addition, the reaction equilibrium temperature is a key factor in the process, with the temperature being influenced by the ratio of (steam + CO2) to O2. Indeed, CO2 is more efficient than steam at reducing the gasifier temperature. Finally, the composition of the gasification agents was optimised by simulations using pure O2-steam-CO2 and air-steam-CO2 mixture as the gasification agents.

In order to investigate the influence of the interfacial angel on failure characteristics and mechanism of combined coal-rock mass, 35 uniaxial/biaxial compressive simulation tests with 5 different interfacial angels of combined coal-rock samples were conducted by PFC2D software. The following conclusions are drawn: (1) The compressive strength and cohesion decrease with the increase of interfacial angle, which is defined as the angle between structure plane and the exterior normal of maximum principal plane, while the changes of elastic modulus and internal friction angle are not obvious; (2) The impact energy index KE decreases with the increase of interfacial angle, and the slip failure of the interface can be predicted based on whether the number of acoustic emission (AE) hits has multiple peaks or not; (3) There are four typical failure patterns for combined coal-rock samples including I (V-shaped shear failure of coal), II (single-fracture shear failure of coal), III (shear failure of rock and coal), and IV (slip rupture of interface); and (4) A positive correlation between interfacial angle and interface effect is shown obviously, and the interfacial angle can be divided into weak-influencing scope (0-15°), moderate-influencing scope (15-45°), and strong-influencing scope (> 45°), respectively. However, the confining pressure has a certain constraint effect on the interface effect.

In order to reveal the stress precursors of the “3.15” rockburst disaster that occurred in the No. 1 working face of Junde coal mine, the combined stress field inversion including static and dynamic stresses was conducted by using P-wave velocity tomography, and the static high-stress concentration regions were further designated. Simultaneously, the evolution of dynamic stress generated by seven periodical caving events of primary roof was analyzed, and the fracturing characteristics were described in detail. Ultimately, the stress precursors of the “3.15” rockburst for early warning were clearly revealed. The main conclusions are as follows: (1) the micro-fissures inside coal and rock mass produce the significant reflection and refraction on the propagation of microseismic (MS) waves, and thus P-wave overall characterizes with lower velocity and higher velocity gradient; (2) after the slightly fracturing of primary roof on March 9, 2013, the maximum stress concentration factor suddenly rises to 20. This sign can be viewed as an early warning precursor of rockburst; (3) until March 12, 2013, the large-scale micro-fractures begin to form inside primary roof, and thus the corresponding high velocity gradient regions are generated. This phenomenon can be regarded as an effective precursor of macroscopic fracturing of primary roof; and (4) before the “3.15″ rockburst, the scope of P-wave velocity gradient in the No. 1 working face does not change significantly. The above findings may put forward a certain reference for accurately warning the stress precursors of rockburst by P-wave velocity tomography.

We sheared layers of polymethyl methacrylate (PMMA) by traditional double-direct shear tests, and synchronously measured the acoustic emissions (AE) generated by shear-slip and friction. Laboratory observations of simulated fault by PMMA materials with zigzag-type gouge showing repetitive, shear-slip events that are reminiscent of earthquakes were verified. In addition, the influencing rules of zigzag size and normal force on shear-slip process and intensity, as well as AE were revealed. Especially, prior to final failure of zigzag, the duration among shear-slip events gradually decreases and shows significant steadiness, which may prove the probability of the obvious foreshock effect to a larger earthquake. Maybe, this work can interpret the shear-slip mechanism of earthquakes and even provide warnings of failure and instability of fault.

In order to analyze the microseismic (MS) effects of hard and thick igneous strata separation and fracturing and the corresponding evaluation index of fracturing intensity, the temporal-spatial evolution of the MS sources generated by igneous strata fracturing in the 10416 working face of the Yangliu coal mine (YCM) was dynamically recurred, and the waveform and frequency-spectrum distribution characteristics of primary and igneous strata fracturing were clearly investigated, respectively. In addition, the relationship between the MS dominant frequency, the energy ratio in low-frequency band and the intensity of igneous strata fracturing was revealed, and the energy ratio of MS event in low-frequency band can be verified as an effective index for evaluating roof fracturing intensity. The work may put forward a certain reference for early warning and evaluating hard and thick roof fracturing and the induced coal-rock dynamic disasters based on in-situ MS observation.

To uncover the failure and instability mechanism of coal-rock combination under loading, it is very crucial to investigate crack development and energy evolution. In this work, the uniaxial compressive and Brazilian split tests of coal-rock combinations were first performed. Secondly, the corresponding numerical models were built using the UDEC-Trigon method. Based on numerical results, the number, length and macroscopic area of cracks during failure and instability were determined, and the crack development and energy evolution rules were analysed. The main conclusions were obtained as follows: 1) the stress thresholds of crack initiation and damage of coal-rock combination rose with the increasing height ratio of coal to rock. The maximum event count of acoustic emission (AE) appeared earlier than the peak strength; 2) the failure and instability of coal-rock combination occurred when crack propagation and connection in central coal exceeded the damage limit. The shear failure was dominant mechanical behaviour of coal with the ratio 9:1 of shear to tensile fractures. The cracks connection was presented as a shear failure surface with an inclination angle of 15°–30° in coal and a vertical tensile failure plane in rock; and 3) the energy evolution in coal-rock combination was described as follows: the larger the height ratio of coal to rock is, the higher the cumulative energy is, and the faster the speed of energy dissipation is, indicating the higher risk of rockburst triggered by failure and instability of coal-rock combination.

Our experimental work was designed to explore the particle size effect of simulated fault gouge on slip characteristics by the conventional double-direct shear friction configuration combined with acoustic emission (AE). The following conclusions were drawn: (1) smaller particles allow for an initially higher compaction rate at a higher speed and longer duration for force chain formation and destruction. The larger the particle size is, the higher the slipping displacement rate is; (2) the smaller the particle size is, the larger the friction coefficient is, and thus the higher the fault strength is. In addition, the larger the shear velocity is, the higher the fault strength is; (3) the smaller the particle size is, the higher the shear stress drop generated by the stick-slip is, and the stronger the dynamic slip intensity for a stick-slip period is; and (4) surface defects of forcing blocks possibly help to embed foregoing “stability” and “stable sliding” into the normal stick-slip stage. Especially, the “stable sliding” is possibly related to formation of stubborn force chains. These findings may shed some insights into further clarification of slipping characteristics and discrimination of precursory signs of fault dynamic instability with different-sized gouge particles.

Summary Traditional gasification parameters, such as cold gas efficiency, hot gas efficiency, or thermal efficiency, only evaluate the heat energy utilisation efficiency of gasifiers and do not take into account the gasification processes expending electricity and other types of energies. Therefore, the energy conversion efficiency cannot be assessed using these parameters. The calculation process on the energy conversion efficiency of underground coal gasification (UCG) is the basis for obtaining quantitative data of carbon emission reduction and establishing the carbon trading methodology of UCG. Moreover, the energy conversion efficiency both for surface coal gasification and UCG is a key research topic because it directly affects the economic and environmental benefits of gasification projects. This study proposed that two parameters, the integrated gasification efficiency (hcom) and the hot gas integrated gasification efficiency ( hcom′), should be included into the coal gasification parameters and used to evaluate the energy conversion efficiency of coal gasification. In addition, the calculation methods of these two parameters for both surface gasification and UCG were established. Using the method, hcom and hcom′, of the UCG and Texaco gasification under the same scale was compared and that of various UCG processes was calculated. The results proved the necessity and reasonability of the two parameters and suggested that a certain amount of CO2 was favourable to improve hcom and hcom′ of UCG. However, a certain amount of pure O2 can improve hcom of UCG without direct influences on hcom′. Under the condition of each process, to maximise hcom and hcom′, there must be an optimal steam (CO2) to O2 rate. Copyright © 2015 John Wiley & Sons, Ltd.

We designed and manufactured several types of simulated faults with different-size rectangular zigzag gouges, and sheared them by traditional double-direct shear tests. Simultaneously, the shear force and corresponding acoustic emissions were recorded during shear-slip of rectangular zigzag gouge, and the variations of shear force and acoustic emission energy characteristics related to shear-slip events were analyzed. Especially, the relationship between shear-slip characteristics and zigzag length and width was also revealed. In addition, the significant differences of slip characteristic parameters between shear-slip of an intact zigzag and friction and sliding on rough plane of a sheared zigzag were summarized, and it might be used to judge the different stages of a fault slip with zigzag gouge. In conclusion, this work may reveal the characteristics of shear-slip and friction under conditions of different-size rectangular zigzag gouges of simulated fault and thus provide valuable insights into precursors of earthquake.

It has a significant and practical meaning for warning precisely gas outburst to reveal microseismic (MS) and acoustic emission (AE) effect of gas outburst precursor. It was thoroughly investigated and discussed on MS and AE effect on an abnormal gas outburst triggered by a strong rockburst using MS- and AE-monitoring systems through spectral analysis technique. We obtained main conclusions are as: (1) MS amplitude prominently decreased prior to outburst, the spectrum significantly moved from extremely low-frequency to high-frequency band, and evolved from “single-peak type” (the center frequency was about 1.5–3.5 Hz) to “multi-peak type” (the peak frequencies were about 25, 50, 75 and 125 Hz, respectively). (2) During the initiative stage of outburst, MS spectrum manifested the broadband distribution, and the predominant frequency was about 20–35 Hz. The high-frequency portion was generated by micro-cracks, and the low-frequency part attributed to macro-fracture for gas outburst channel. (3) The rockburst stimulated micro-fissures formation for gas emission channels, and maintained the event count of MS and AE signals in a relatively higher level, which is a major discrepancy to the common belief that both the total energy and event count should simultaneously and suddenly reduce to the lowest value in a non-outburst coal seam.

To reveal acoustic emission and electromagnetic emission effects during hard rock impact failure is a crucial issue for monitoring and warning rockburst risk induced by hard roof fracture and fall. The presented research focuses on acoustic emission and electromagnetic emission and microseismic effects detected during laboratory tests and by in situ multi-parameter observations, and the field observations agreed satisfactorily with the experimental evidences. The following main conclusions were drawn: (1) the stress level, frequency of micro-cracks, and impact failure regularity of hard rocks can be revealed with electromagnetic emission and acoustic emission/microseismic parameters, respectively; (2) acoustic emission/microseismic event counts can directly reveal the cracks change in rocks, and the initiation, propagation, and coalescence of micro-cracks can be presented as first increase, followed by decrease in acoustic emission/microseismic event counts; (3) in most cases, only when stress suddenly decreases or the rock final collapses, acoustic emissions show obviously abnormal; and (4) acoustic emission/microseismic can be more effectively applied to warn rockburst danger. The above conclusions may shed light on the effective monitoring and warning methods of rockburst triggered by hard roof fall, and events contribute to some interpretations to originally transient precursors of hard rock fracturing.

Strong rockburst disaster in deep coal mines is easily triggered by the higher static stress of mining coal seam and the dynamic stress wave disturbance generated by hard and thick roof fall. Revealing the frequency-spectrum evolutionary rule of microseismic (MS) signals before and after roof fall is a very important issue for evaluating and forecasting rockburst danger. By experimental tests for combined coal and rock samples rockburst failure and in-situ measurements in a strong rockburst coal mine, the frequency-spectrum evolutionary rule and precursory characters were analyzed in detail. The following conclusions were drawn: (1) Precursory MS signals show the elevated energy and events, lower frequency and trend of spectrum moving to low-frequency band; (2) mainshock signals of rockburst are characterized by maximum amplitude (vibration velocity), wider spectrum, and higher predominant frequency; and (3) aftershock signals are characterized by the sudden decreasing amplitude, highest predominant frequency, and trend of spectrum moving to high-frequency band.

As a tough problem in coal mines, there is not an effective solution to rockburst evaluation and prediction as yet. In this paper, an attempt to investigate a rockburst forecasting method was undertaken by applying small scale, laboratory modeling of the coal mine roof, coal and its floor. According to rockburst danger evaluation and forecasting in deep coal mines on the basis of microseismic (MS) monitoring, the frequency-spectrum evolution was analyzed in detail by the band-stop filter and Fourier transform of MS signals monitored in time. Research results show that a strong mainshock induced by coal and rock sample bursting failure would commonly be introduced when the predominant frequency-spectrum of MS signals begins to move to lower band and the vibration velocity gradually increases, and the signals closed to mainshock, precursor signals, which indicate the tendency of increasing low-amplitude and the decreasing high-frequency. Moreover, it is also found that the rockburst disaster intensity increases with the increase of vibration velocity of precursor signal, and it is opposite with the predominant frequency of precursor signal.

For the purpose of having a better understanding of failure mechanisms of rock fracturing in mines, the equivalent point source models of tensile, shear and explosive seismic events were established, and the relationship between far-field seismic displacements of the waves and the corresponding equivalent forces were analyzed as well. Based on the results of a microseismic monitoring carried out in the mining progress of 9202 working face under the upper remnant coal pillar in Sanhejian Mine, the waveform features of the seismic events associated with different failure modes were further analyzed. The results show that the signals corresponding to different failure mechanisms have different radiation patterns of the seismic displacements, and different characteristics in waveform features, such as dominant frequency, energy released, the ratio of S- to P-wave energy, and so on. In addition, the rock burst happened in the high stress zone is mainly the result of the strong shear fracturing in the mining process. The results of this study have significantly improved the understanding of the characteristics of the failures associated with underground mining, and will greatly benefit the prevention and control of rock burst hazards in burst-prone mines.

Rock bursts signify extreme behavior in coal mine strata and severely threaten the safety of the lives of miners, as well as the effectiveness and productivity of miners. In our study, an elastic-plastic-brittle model for the deformation and failure of coal/rock was established through theoretical analyses, laboratory experiments and field testing, simulation and other means, which perfectly predict sudden and delayed rock bursts. Based on electromagnetic emission (EME), acoustic emission (AE) and microseism (MS) effects in the process from deformation until impact rupture of coal-rock combination samples, a multi-parameter identification of premonitory technology was formed, largely depending on these three forms of emission. Thus a system of classification for forecasting rock bursts in space and time was established. We have presented the intensity weakening theory for rock bursts and a strong-soft-strong (3S) structural model for controlling the impact on rock surrounding roadways, with the objective of laying a theoretical foundation and establishing references for parameters for the weakening control of rock bursts. For the purpose of prevention, key technical parameters of directional hydraulic fracturing are revealed. Based on these results, as well as those from deep-hole controlled blasting in coal seams and rock, integrated control techniques were established and anti-impact hydraulic props, suitable for roadways subject to hazards from rockbursts have also been developed. These technologies have been widely used in most coal mines in China, subject to these hazards and have achieved remarkable economic and social benefits.