High-efficiency maintenance and control of the deep coal roadway surrounding rock stability is a reliable guarantee for sustainable development of a coal mine. However, it is difficult to control the stability of a roadway that locates near a roadway with large deformation. With return air roadway 21201 (RAR 21201) in Hulusu coal mine as the research background, in situ investigation, theoretical analysis, numerical simulation, and engineering practice were carried out to study pressure relief effect on the surrounding rock after the severe deformation of the roadway. Besides, the feasibility of excavating a new roadway near this damaged one by means of pressure relief effect is also discussed. Results showed that after the strong mining roadway suffered huge loose deformation, the space inside shrank so violently that surrounding rock released high stress to a large extent, which formed certain pressure relief effect on the rock. Through excavating a new roadway near this deformed one, the new roadway could obtain a relative low stress environment with the help of the pressure relief effect, which is beneficial for maintenance and control of itself. Equal row spacing double-bearing ring support technology is proposed and carried out. Engineering practice indicates that the new excavated roadway escaped from possible separation fracture in the roof anchoring range, and the surrounding rock deformation of the new roadway is well controlled, which verifies the pressure relief effect mentioned. This paper provides a reference for scientific mining under the condition of deep buried and high stress mining in western China.

For large underground coal mines producing 10 million tons a year, rapid excavation and stability of deep roadways are pivotal to ensure sustainable, safe, and efficient production. This paper provides a case study of Hulusu Coal Mine in Inner Mongolia, where roadway excavation speed was insufficient to meet production needs. Moreover, deformation in the roofs of the roadways was severe. To achieve rapid excavation and control the stability of deep roadways, a new support system was proposed and constructed in a roadway at a depth of 640 m. The system consisted of long flexible bolts pretensioned to high levels and spaced at large intervals. Roadway excavation and construction of a support system were conducted simultaneously. Field measurements indicated that the new support system effectively controlled deformation and fracture development during excavation and mining. Maximum displacements of the roof during excavation and mining were 10 and 30 mm, respectively. The axial load on bolts surged during excavation as a result of slight deformations caused by excavation operations. This active response of the bolts is beneficial to the prevention of roof deformation during excavation and mining. During mining, fissures propagated up to only a depth of 1.4 m into the surrounding rock mass. The new support system formed a thick reinforced anchorage zone, which greatly improved the bearing capacity of the roof. Compared with the previous support system, the new system allowed the maximum excavation speed (31.5 m/day) to increase by 85.3%. This successful case provides a practical reference for similar roadway projects.

The stability of a deep composite roof is a powerful guarantee for the safe and efficient production of a coal mine. The coal–rock combination, the single rock or coal bodies have different bearing capacity; thus, we can accurately obtain the deformation field evolution and failure mechanisms of the combination, which is useful in the deformation control of a composite roof. In this study, based on the digital speckle correlation method (DSCM), a uniaxial compression test was applied to coal–rock combinations with different height ratios. The results revealed that the compressive strength, elastic modulus, and secant modulus of the combination gradually decreased, while the decreasing amplitude weakened with the increase of coal height. Additionally, the strain field map of the combination had different characteristics in different stages. As the height of the coal body continuously increased, the gradient of the strain cloud and the area of local strain increase moved upwards. Moreover, the cracks caused by the failure of the coal body in the combination triggered the failure of the rock body. According to the test results, two principles are proposed for the deformation control of the composite roof, and are expected to be useful in applications for the similar geological conditions.

Goaf-side roadway driving could not only notably reduce the loss of coal resources and improve the coal recovery rates, but also greatly mitigate the imbalance between excavation speed and production needs, which are able to prolong the service life of the mine and are pivotal to sustainable and efficient development of underground coal mines. However, it is difficult to control the stability of the goaf-side roadway, especially under mining disturbance of another adjacent coal working face. In order to control the stability of the goaf-side roadway, Haulageway 1513 in the Xinyi Coal Mine of China, under mining disturbance, theoretical analysis, numerical simulation, and engineering practice were carried out to reveal the mechanism of overburden key strata fracture, stress distribution, and deformation characteristics of the surrounding rock of the goaf-side roadway due to mining disturbance. Results showed that some key strata above Goaf 1512 did not fracture due to the influence of the strata caving angles. However, these key strata would fracture and break into rock blocks when suffering from mining disturbance of the adjacent coal working face, which changed the stress distribution and increased the deformations of the surrounding rock of the goaf-side roadway. The combined techniques of pressure relief and bolt support were proposed and carried out to control the stability of the goaf-side roadway. Engineering practice indicated that the maximum deformations of the roof and sidewall-to-sidewall were 220 mm and 470 mm, respectively. The deformations of the goaf-side roadway under mining disturbance were efficiently controlled.