Outburst Coal Seam Research Articles

Research on Application of Directional Long Drilling Fracturing Technology in 1930 Coal Mine

The solidity coefficient of the main coal seam in Xinjiang Coking Coal Group 1930 Coal Mine is below 0.3, which is a soft outburst coal seam with poor air permeability, a small effective range of gas drainage drilling, low porosity of soft coal seam, low gas drainage rate, and unsatisfactory drainage effect. Using directional drilling equipment to construct directional long drilling, combined with the hydraulic fracturing pump set independently developed by Xi’an Research Institute, directional drilling were constructed in the 1930 coal mine 1600 level 6# coal seam, and hydraulic fracturing was carried out. The results show that after the hydraulic fracturing of the 6# coal seam, the production has been stable for nearly 6 months. During the period, the average gas drainage rate of the drilling was 134.9m3/d (maximum 561.7m3/d), which was 2.10 times that before fracturing, The average drainage concentration is 1.90%, which is 1.45 times that before fracturing. At present, the total amount of gas drainage is 25,900 m3, which is 4 times the original amount. This technology has achieved enhanced permeability of broken soft coal seam, increased drainage volume, extended drainage time, and advanced gas outburst elimination at a long distance. It provides a technical guarantee for the enhanced permeability enhancement of the broken soft low-permeability outburst coal seam and the high-efficiency underground gas drainage.

Influence of deep magma-induced thermal effects on the regional gas outburst risk of coal seams

The thermal effect caused by deep magma intrusion can not only accelerate the metamorphism of coal body, but also bring additional thermal field that changes the mechanical environment of coal seams, thereby affecting the permeability of coal seams. Different from shallow coal resources, deep coal resources are in a mechanical environment characterized by limited stress and strain. Thus, the thermal effect has a more significant influence on the distribution and permeability characteristics of deep coal seams. In this study, the evolution history of highly metamorphic coal seams in Yangquan mining area was analyzed, and the main effect of magmatic activity on coal seams was obtained. Based on the determined vitrinite reflectance data of typical mines in Yangquan mining area, the maximum paleotemperature was calculated by adopting the Barker’s method. Furthermore, the paleotemperature distribution in Yangquan mining area was summarized, and its relationship with the metamorphic degree was acquired. Then, a new permeability model considering the thermal strain was proposed to analyze the permeability evolution in deep coal seams at different ground temperatures. Finally, through a combination of the results of gas pressure and outburst number in Sijiazhuang Mine, Yangquan No. 5 Mine and Xinjing Mine, the influence of ground temperature on the gas outburst risk in Yangquan mining area was explored. The following conclusions were drawn: The maximum paleotemperature in Yangquan area can be 303 °C. In addition, the paleotemperature in the south is higher than that in the north of Yangquan mining area. The various temperatures at different depths bring about different degrees of thermal stress to different coal seams, leading to different strains. Under the fixed displacement boundary conditions in the deep, the coal seam folds and bends to varying degrees. Moreover, the difference in the ground temperature raises the a value of coal seams and lowers the permeability, which promotes the formation of gas-rich zones and increases the risk of coal seam outburst. The research results can help mines to make proper gas disaster prevention plan for different zones.

Research on safe and efficient drilling technology of soft outburst coal seam

In soft coal bedding drilling hard into the problem of hole, based on the drilling of coal in the process of motion, from two aspects to improve the traditional drilling technology, selection of high power, large torque drill and selecting reasonable parameters of drilling tools and better way of powder, formed a “high power drill, shallow blade spiral drill pipe, wind pressure in the wind” of the construction process. The field application test was carried out in Xinxin Coal Mine of Yunnan Province, and the test results show that the average monthly footage of drilling rig is 8000 m/rig•month. The average depth is 137m, the primary pore formation rate reaches 90%. Compared with the original drilling technology, the new technology increases the average hole depth by 12%∼70%, the drilling efficiency by 30%∼46%, the extraction concentration by more than one time, and the single hole extraction amount by 33.6%. The drilling technology of soft outburst coal seam has improved the drilling efficiency and realized the full coverage of gas drainage in working face, which is worthy of reference and reference in soft coal seam mine.

Substantiation of outburst danger automated monitoring on amplitude frequency characteristic median of the operating equipment noise and methane concentration in the mine working medium

Basic requirements to the methods of current outburst danger prediction are formulated. The methods must be applied in the process of mining not interfering with the works and taking into account basic factors that cause the outbursts and they should have scientifically grounded methodology for fast definition of outburst danger criteria under certain mining, geological and engineering conditions. It is shown that geophysical prediction methods can meet the first requirement. Rock pressure, in-situ gas pressure and coal strength are taken as basic factors of outburst danger. Some well-known geophysical method such as a method of acoustic emission, a spectral-acoustic method, a gas analytical method and a temperature method taken separately do not satisfy the second and the third requirements. That is why it is suggested controlling rock pressure by spectral-acoustic method, gas pressure by means of gas analyser on methane concentration at the face of the working while mining coal and coal strength should be measured by a strength measuring device. To improve the accuracy of the prediction a version of spectral-acoustic method based on dependency of amplitude-frequency characteristic median of mining operating equipment noise on average stresses at the section between the source of the noise and geophone. The criterion of outburst danger is substantiated and the algorithm for arranging automated monitoring of coal seam outburst danger is offered.

An experimental study on coal damage caused by two-phase displacement of CO2- alkaline solution

Two-phase displacement of CO2- alkaline solution technology was proposed to address the obvious problems existing in the current coal mine gas control technologies, such as the gas enrichment and outburst risk caused by tradition CO2 injection technology, and the poor effect of conventional coal seam water injection technology. In order to investigate the damage characteristics of coal pore structure and permeability caused by two-phase displacement of CO2- alkaline solution, the composition and microstructure of coal after two-phase displacement of CO2- alkaline solution were tested experimentally, and the permeability experiment of two-phase displacement of CO2- alkaline solution was carried out. The results show that the reaction degree and dissolution of CO2-containing coal with alkaline solution are stronger than those with distilled water. The reaming effect of alkaline solution on CO2-containing coal is stronger than that of distilled water, and the two-phase displacement of CO2- alkaline solution has the greatest influence on mesopore and macropore; After two-phase displacement of CO2- alkaline solution, the permeability of coal sample increased by 47.6%–108.6%, and the water content of coal sample increased by 109%. The two-phase displacement of CO2- alkaline solution leads to the secondary development of coal pores, which significantly changes the coal pore structure, increases the permeability and water content of coal body, and thus obviously increases the gas extraction effect to reduce coal seam outburst risk and ensure coal mine safety production.

Stability Assessment of Deep Three-Soft Outburst Coal Seam Roof Based on Fuzzy Analytic Hierarchy Process

The stability of deep “three-soft” coal seam roof has always been a key issue in coal mining. There are a lot of factors affecting the stability of deep three-soft coal seam outburst roof. However, there is currently no definite method able to draw an accurate assessment conclusion on roof stability. In order to accurately determine the main influencing factors of the stability of deep three-soft coal seam outburst roof and reduce the loss of coal production, this paper performed three-soft coal seam risk identification on Lugou Mine based on the introduction of the fuzzy analytic hierarchy process theory. 23 main risk factors were identified. Then, it established a hierarchical structure model of coal seam roof stability in accordance with experts’ opinions. The analytic hierarchy process was used to calculate the weights of indicators at all levels. Next, the paper used the fuzzy comprehensive evaluation method and expert scoring to evaluate various risk factors in the indicator system, as well as the overall safety level. The results showed that the deep three-soft coal seam stability of Lugou Mine ranks the third hazard level. The main risk and harmful factors include safety awareness, safety monitoring system, roof weakness, ventilation system, fire-fighting system, and rock bolt quality. In response to the evaluation results, this paper formulated corresponding control measure in terms of ventilation risk, safety monitoring risks, construction personnel risks, and fire protection risk to reduce losses in the mining process, providing a new evaluation method for the stability assessment of deep outburst coal seam roof.

Gas Expansion Energy Model and Numerical Simulation of Outburst Coal Seam under Multifield Coupling

Due to the insufficient understanding of the outburst mechanism, the coal and gas outburst disasters in China are more serious. Gas expansion energy is the main source of energy that causes outburst. In order to explore the distribution law of gas expansion energy in outburst coal seams, a gas-solid coupling equation of outburst coal seams was established. The distribution law of coal stress field, deformation field, gas flow field, and gas expansion energy were simulated and analyzed by using COMSOL Multiphysics. The results showed that from the excavation face to the deep part of coal seam, the stress presented unloading zone, stress concentration zone, and original stress zone. The volumetric strain and permeability reached the minimum, while the gas pressure reached the maximum at the peak value of vertical stress. As time goes on, the gas pressure in the fracture near the working face gradually decreased and was less than the pressure in coal matrix. The total gas expansion energy consists of free gas and desorption gas expansion energy. Affected by the excavation, free gas expansion energy maintained a constant value in the original coal seam and gradually decreased in the area close to the working face. The expansion energy provided by desorption gas was zero in the original coal seam. And it first increased and then decreased rapidly near the working face. Compared with stress and coal seam thickness, gas pressure and initial diffusion coefficient had significant influence on gas expansion energy of coal seam. When the diffusion coefficient was greater than 1e-9 m2/s, the gas expansion energy of the coal seam near the working face was significantly higher than that of the original coal seam, which had the risk of inducing outburst.

Theoretical Study and Numerical Simulation Research on the Effect of Coal-Rock Interface on Multistaged Fracturing in the Roof of Outburst Coal Seam

Multistaged fracturing in the roof of outburst coal seam is an efficient and creative technology for coalbed methane (CBM) drainage, which can effectively improve the permeability of coal seam. To reveal its mechanism of permeability enhancement, the effect of coal-rock interface on multistaged fracturing in the roof of outburst coal seam was simulated and discussed in this paper. Firstly, the lithological difference between outburst coal seam and roof was compared, and the concept and significance of multistaged fracturing in the roof of outburst coal seam were explained. Then, the mechanical conditions of multiple fractures in the roof traversing coal-rock interface were analyzed. The effects of mechanical parameters on multiple fractures were numerically simulated. The results indicated that fracturing borehole in adjacent rocks of outburst coal seam is much easier to drill and maintain gas drainage. Considering gas drainage efficiency and avoiding being blocked by coal fines, multistaged fracturing borehole is generally drilled in the stable rock stratum of roof. Whether the multiple fractures in the roof can traverse coal-rock interface is related to mechanical parameters of coal and rock, friction factor of coal-rock interface, angle between horizontal profile and coal-rock interface, cementing strength of coal-rock interface, minimum horizontal stress, and other factors. Higher fracturing fluid pressure contributes to propagating from the reservoir with low elastic modulus to the one with high elastic modulus for hydraulic fracture. Hydraulic fracture is more likely to propagate in the rock stratum with high brittleness index. The research results can improve multistaged fracturing theory and provide technological support for field test.

Coupling Technology of Deep-Hole Presplitting Blasting and Hydraulic Fracturing Enhance Permeability Technology in Low-Permeability and Gas Outburst Coal Seam: A Case Study in the No. 8 Mine of Pingdingshan, China

The current study aims to analyze the principles of integrated technology of explosion to tackle the problems of coal seam high gas content and pressure, developed faults, complex structure, low coal seam permeability, and high outburst risk. Based on this, we found through numerical simulation that as the inclination of the coal seam increases, the risk of coal and gas outburst increases during the tunneling process. Therefore, it is necessary to take measures to reduce the risk of coal and gas outburst. We conducted field engineering experiments. Our results show that the synergistic antireflection technology of hydraulic fracturing and deep-hole presplitting blasting has a significant antireflection effect in low-permeability coal seams. After implementing this technology, the distribution of coal moisture content was relatively uniform and improved the influence range of direction and tendency. Following 52 days of extraction, the average extraction concentration was 2.9 times that of the coal seam gas extraction concentration under the original technology. The average scalar volume of single hole gas extraction was increased by 7.7 times. Through field tests, the purpose of pressure relief and permeability enhancement in low-permeability coal seams was achieved. Moreover, the effect of gas drainage and treatment in low-permeability coal seams was improved, and the applicability, effectiveness, and safety of underground hydraulic fracturing and antireflection technology in low-permeability coal seams were verified. The new technique is promising for preventing and controlling gas hazards in the future.

Study on Outburst Risk Prediction Sensitivity Indexes and Its Critical Value of the Stress-dominated Outburst Coal Seam

According to that outburst in the mining area is the dominant stress type and they occur near the geological structure, taking Sangshuping NO.2 coal mine as the research background, the drilling cuttings weight S, gas desorption index of drilling cuttings Δh2&K1 in the investigated area were statistically analysed by combining laboratory analysis with field investigation. The study determines that the sensitive indexes of outburst risk prediction in NO.3 coal seam working face are the drilling cuttings weight S and gas desorption index of drilling cuttings Δh2; the critical values of normal and abnormal geological conditions are determined, which provides basis for prediction of No.3 coal seam working face in test area.

Research and Application of Hydraulic Punching Pressure Relief Antireflection Mechanism in Deep “Three‐Soft” Outburst Coal Seam

To solve the problems of gas predrainage in deep seams with “three softs” and low‐air permeability, hydraulic punching pressure relief antireflection technology is proposed on the basis of the research background of gas predrainage technology in Lugou Mine to alleviate technical problems, such as low gas drainage efficiency, in this mine. Through the analysis of the mechanism of hydraulic punching and coal breaking, combined with FLAC3D software, a hydraulic punching pressure relief antireflection model is established. Then, the fracture radii of coal rock are simulated and calculated. The results show that, under hydraulic punching with a water pressure of 10 MPa and coal outputs of 3 m3, 6 m3, 9 m3, and 12 m3, the fracture radii of coal and rock are 3.4 m, 4.8 m, 5.5 m, and 5.9 m, respectively. Using the software to fit the relationship between coal output V and hydraulic punching fracture radius R under the same water pressure, R = 2.32479 V0.3839 is obtained. The field test is carried out in the bottom drainage roadway of 32141 in Lugou Mine. The application effect is as follows: the gas concentration of hydraulic punching with a coal output of 3 m3 is twice that of ordinary drilling, and the coal output of hydraulic punching with a coal output of 6 m3 is four times that of ordinary drilling. The extraction concentration is four times that of ordinary drilling, and the extraction concentration of hydraulic punching with a coal output of 9 m3 is 6.4 times that of ordinary drilling. Combining the results of the numerical simulation and taking into account the actual construction situation on site, the coal output of water jetting from the borehole is 9 m3, and the fracture radius is 5.5 m. This outcome means that the effective half radius is 5.5 m, and the borehole spacing is 7.7 m. These values are the construction parameters for large‐scale applications. This proposal provides effective technology and equipment for gas drainage in the deep three‐soft coal seam. Consequently, it has promotion and reference significance for gas drainage in coal seam of the same geological type.

Numerical Simulation and Theoretical Study of the Effect of Fracturing Strata on Multi-Stage Fracturing in the Roof of an Outburst Coal Seam

ABSTRACT Multi-stage fracturing is one of the key techniques that use boreholes instead of tunnels and can effectively transform a coalbed methane (CBM) reservoir and increase its permeability. However, due to the lack of systematic and in-depth research on the use of multi-stage fracturing for gas drainage, the development of multi-stage fracturing is slow, and there are many problems, which to some extent restrict the application of multi-stage fracturing in low permeable outburst coal seams. In this study, the No. 21 coal seam in the Zhongmacun Coal Mine was taken as the research object, and the lithologies of the roof and floor of the No. 21 coal seam and the in-situ stress were tested. Then, three types of fracturing strata were numerically simulated to study the effect of fracturing strata on the fracture initiation, propagation and morphological characteristics induced by multi-stage fracturing in the roof of an outburst coal seam. The influence of the brittleness index of fractured strata on the formation of a fracture network was analyzed theoretically. The results indicate that the sequence in decreasing order of the fracturing range and failure mode is the medium sandstone model, the sandy mudstone model, and the mudstone model. It is useful to form a fracture network when the fractured strata in the roof of the outburst coal seam is a medium sandstone or siltstone. By comparing the brittleness index of the roof and floor lithologies of the No.21 coal seam in the Zhongmacun Coal Mine, the proper strata for the multi-stage fracturing in the roof of the outburst coal seam was selected. The results of this study provide a theoretical basis and data support for selecting proper strata for multi-stage fracturing in the roof of an outburst coal seam.

Analysis of pressure relief and outburst prevention effect and mining depth effect of floor roadway in single serious outburst coal seam

In order to solve the serious problem of single serious outburst coal seam gas disaster, based on the gas geological conditions of Jiangxi Fengcheng Qujiang company, theoretical analysis, numerical simulation, field test and other comprehensive research methods were used to analyze the partition fracture law of roadway surrounding rock under different mining depth conditions. The results show that: under the conditions of high ground stress, high temperature and other environmental conditions, the radius of pressure relief loose circle of surrounding rock of roadway is significantly increased, and it is significantly larger than that of shallow part. In the deep area of - 800m elevation, the distance between floor roadway and coal seam is optimized to be 12 ~ 15m. The field test results show that the original permeability coefficient of overlying coal seam of floor roadway increases by 55.74 times, and the pressure relief effect is good.

A Multiscale Structural Analysis of Soft and Hard Coal Deposits in Deep High‐Gas Coal Seams

In recent years, with the increases in coal mining depths, the risk of coal seam outburst occurrences has increased. Therefore, it is of major significance to study the multiscale structures of soft and hard coal deposits in order to prevent and control the coal and gas outbursts. In this research investigation, soft and hard coal multiscale structures were comprehensively examined using various laboratory methods. The results revealed the following: (1) From a macrostructural aspect, the physical and mechanical properties of the soft coal were weaker than those of the hard coal. It was found that the majority of the examined specimens were characterized by scaly structures without blocks larger than 50 mm. The hard coal was observed to be mainly massive with only a small part being clastic. Therefore, the structural characteristics were considered to be stable. (2) From a microstructural perspective, the surfaces of the soft coal specimens were observed to be rough. The pores were found to be more developed, with the edge of pores being mainly hackly. At the same time, fractures were also relatively developed, showing good connectivity. (3) From a micropore structural perspective, it was found that the BET‐specific surface areas and BJH‐specific surface areas of the soft coal specimens were higher than those of the hard coal specimens, which indicated that the gas adsorption and diffusion migration abilities of the soft coal were greater than those of the hard coal. (4) It was suggested from the study results that the ventilation and gas extraction processes should be strengthened in the mining activities of coal seams with high, soft stratification content. At the same time, the methods used for water injection modification should be enhanced in order to improve the mechanical stability of soft coal. Consequently, the instantaneous released gases will be decelerated, and the occurrences of coal and gas outburst events in mine working faces can be prevented.

Experimental Study Via Dynamic Prediction Model on High Pressure Hydraulic Slotting and High Efficiency Gas Drainage Technology under Complex Geological Conditions

In view of the difficult problem of dynamic disaster prevention and control in deep high gas, high stress and low permeability coal seam, the change law of drilling stress after seam cutting through drilling and bedding drilling is revealed by using numerical simulation method. The high-pressure hydraulic slotting method is used in Xinji Mining Area to carry out pressure relief and permeability increase test on coal seams. The test results are as follows: the slotting radius reaches 2.5m, and the net amount of gas extraction is 4.5 times higher than that of ordinary drilling holes, so as to realize efficient gas extraction in coal seams and reduce the risk of coal seam outburst. The technology of high-pressure hydraulic slotting, pressure relief and permeability enhancement can be used as a supplementary means for the prevention and control of coal seam dynamic disasters in deep mines.

A Novel Apparatus for Dynamic-Static Coupling Tests on Gas-Adsorbed Coal

Abstract Laboratory testing is an efficient way to study the deformation and failure mechanisms of outburst coal. However, existing devices can only perform static loading tests on gas-adsorbed coal, which is not necessarily the stress condition encountered in coal seam outburst. Additionally, the traditional testing methods used by existing devices are not conducive to acquiring the dynamic performance of gas-adsorbed coal. In this study, a novel apparatus was developed to visualize gas-solid coupling. The apparatus can perform combined loading corresponding to a “static stress + impact disturbance” and a “static stress + gas pressure relief disturbance” on gas-adsorbed coal. The complex dynamic characteristics of the gas-adsorbed coal are comprehensively monitored by high-speed photography and a self-developed circumferential displacement test device. The effectiveness and reliability of the novel apparatus were confirmed by carrying out mechanical tests on gas-adsorbed coal subjected to a pressure relief disturbance and an impact disturbance. The test results showed that a dynamic disturbance can cause a sudden drop in the bearing capacity, a sudden increase in the volumetric strain, and rapid crack propagation in gas-adsorbed coal. The disturbance can even induce coal burst failure, which is very similar to the outburst phenomenon. The developed scientific apparatus can be used to study the deformation and failure mechanisms of gas-adsorbed coal under combined dynamic and static loading.

Addressing the gas emission problem of the world’s largest coal producer and consumer: Lessons from the Sihe Coalfield, China

Exploitation of deep-lying coal resources, an inevitable result of the conflict between the depletion of shallow coal resources and the enormous demand for energy, is subject to safety accidents caused by increased risks of coal and gas outbursts. Factors such as low gas extraction efficiency resulted from poor air permeability of coal seams, failure of extracting methane in coal mine and low utilization rate of the methane extracted from coal mine not only cause serious greenhouse effect, but also waste a lot of energy and fuel. Recent innovations have seen that the new elements of three zone linkage based on the joint mining of coal and gas is used to ensure the safety of workers and achieve the maximum energy comprehensive utilization. Sihe coalfield represents a particularly challenging mining environment for applying this practice. Due to the high risk of coal seam outburst, mining disturbance will not only cause coal and gas outburst and cause casualties, gas emissions will also cause serious greenhouse effect and energy waste. Sihe coalfield has formed a green coal mining mode of low-carbon and environmental protection, which provides attractive experience and lessons for the application of other coal mines at home and abroad. This approach achieves multiple benefits: large-scale extraction and utilization of CBM resources, safe and efficient production of coal areas, and reduction in greenhouse methane emissions. The successful application of this method to Sihe coalfield provides a new way of gas management for other coal mines with similar geological conditions. In view of the extreme nature of Sihe minefield, it will be easier to implement in other coal mines.

Reasonable Width of Narrow Coal Pillars Along Gob-side Driving Entries in Gas Outburst Coal Seams: Simulation and Experiment

In gob-side entry driving, the coal pillar width determines the stability of the surrounding rock and the pillar itself. Thus, to improve the stability of gas outburst coal seams, the reasonably narrow width of the coal pillars of the 40403 working face of the Shengyuan coal mine 4# was theoretically determined. Through two-dimensional simulations, the surrounding rock stability for a roadway with different coal pillar widths was evaluated. The mechanism of the surrounding rock displacement and stress distribution with the increase of the coal pillar width was also defined; for pillar widths of 2–4, 4–6, and 6–10 m, the vertical stress distribution was approximately triangular, trapezoidal, and parabolic, respectively. The coal pillar displacement was significantly greater on the goaf side than on to the roadway side. As the width of the coal pillar was incremented, its displacement on the goaf side increased, while that on the roadway side remained relatively small. The combination of the simulation results with on-site measurements finally revealed that 5 m is a reasonably narrow coal pillar width. Then, the findings were successfully applied to the 40403 working face of the Shengyuan coal mine 4#, achieving good outburst prevention and cost reduction.

Effect of faults on the pore structure of coal and its resultant change on gas emission

Faults are one of the important factors influencing coal and gas outburst in outburst coal seams. In this paper, 3# and 8# coal seams in Xinjing Coal Mine were taken as the research objects in the hope of revealing the mechanism of how faults affect coal seam. The pore structure and its resultant change on gas emission of coal samples at different distances from the faults were studied by means of scanning electron microscope, nuclear magnetic resonance and adsorption/desorption experiments. The results show that the fault significantly influences the pore structure. The coal sample closer to the fault has a greater number of well-developed macropores and fractures as well as better connectivity between pores and fractures. Besides, compared with 8# coal seam, 3# coal seam which is more notably impacted by the fault possesses a more developed pore structure at the micron scale. As the distance from the fault increases, the gas adsorption volume declines while the desorption hysteresis coefficient grows on the whole. The coal sample closer to the fault adsorbs a larger volume of gas and meanwhile desorbs gas more easily, so it is more prone to coal and gas outburst. The initial velocity of gas emission falls gradually as the distance from the fault increases. The desorption hysteresis coefficient generally drops with the rise of the initial velocity of gas emission. Judged by the influence scope of the fault, 3# coal seam possesses a much higher outburst risk than 8# coal seam. The research results reveal the mechanism of how faults affect coal pore structure and gas sorption characteristics, which can provide a basis for the prevention and control of gas dynamic disasters in fault-containing coal seams.

A Method of Quick and Safe Coal Uncovering by Hydraulic Fracturing in a Multibranch Radial Hole with a Coalbed Methane Well

Coal and gas outburst accidents occur most frequently during coal uncovering operation, and uncovering-induced outburst accidents have caused great economic losses and casualties. In order to quickly and safely uncover the outburst coal seam at the air intake shaft in panel 2, Zhaozhuang Coal Mine has come up with the technology of multibranch radial borehole hydraulic fracturing (MRBHF) coal uncovering technology in the surface coalbed methane (CBM) well. By conducting fracturing of constructed radial boreholes in the CBM well, the technology increases fractures, enhancing coal permeability and raising gas drainage volume in the uncovering area. It brings the following three major benefits: (1) uncovering coal efficiently, rapidly, and safely; (2) greatly reducing engineering quantity, coal uncovering period, and construction cost, i.e., significantly improving the economic benefits; and (3) efficiently reusing the CBM well. Compared with conventional uncovering measures, the proposed technology shortens the uncovering period by 118 d, enhances the coal seam permeability by 3.55 times, raises the gas drainage rate by 22%, increases the gas drainage volume by 1.93 times, and reduces the engineering volume of drilling by 12,000 m. The safe, rapid, economical, and applicable technology provides scientific guidance and reference for domestic and foreign shaft coal uncovering engineering and possesses important economic and social values and application prospect for safe and efficient production of coal mines.