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The instability control of deep mining roadway is currently dominated by ejection and grouting, as well as floor support, which contradicts the economic and excavation efficiency of production. Taking the failure site of Xin'an Coal Mine in China as an example, this paper systematically analyzes the failure characteristics of supporting components, crack propagation, and surrounding rock deformation in situ, and the impact of failure on the rights and interests of staff, enterprise benefits, and low-carbon environmental protection. Then, a three-way continuous anchorage theory and the derived control technology are proposed based on the exploration of the instability mechanism. Besides, the UDEC Trigon model is adopted to reproduce the instability process and demonstrate the effect of the proposed control technology. According to the subsequent industrial test, the plastic deformation developing from shallow to deep parts leads to the bending, subsiding, swelling, and deformation of rock mass within 5.5 m of the roof, and the surrounding rock failure mainly features the shear failure in the middle of the tail of the supporting components and anchorage relaxation. Meanwhile, it wrecks huge havoc on the rights and interests of staff, enterprise benefits, and CO 2 emission. Following the smooth application of the new technology to roadway excavation, the roof subsidence and two side displacements are reduced by 91.18% and 58.5%, respectively, compared with the original scheme, the rock mass fractures within 1.71 ~ 3.92 m of the roof is effectively sealed, the evolution depth of bed separation is down by 78.6%, and the excavation efficiency rises by 50% while ensuring the supporting cost. In addition, the defects of the new technology in engineering application are also discussed. Accordingly, the R&D and application of this new technology provide a positive reference for the efficiency control of deep mining roadway. Highlights: A three-way continuous anchorage theory and relevant technique are proposed. Multiscale original position analyses are conducted on the failure features of deep coal roadway. The impact of surrounding rock instability on sustainability was considered for the first time. The new scheme reduces roof subsidence by 91.2% and sides' displacement by 58.5%. [ABSTRACT FROM AUTHOR]

Aiming at the problem of mining coal resources under the Yuxing Mine Ecological Park in Inner Mongolia, China, we adopted a continuous mining and continuous backfilling (CMCB) cemented-fill mining method; based on the systematic description of the mining and backfilling craft of the CMCB mining process, comprehensive use of theoretical analysis, numerical simulation, and similar simulation test methods to analyze the control mechanism of overlying strata. By establishing the mechanical model of roof movement for the CMCB mining, the roof deflection curve equation is deduced, and the roof instability criterion is put forward based on the maximum tensile stress criterion. Numerical simulation showed that the stress curve at the shallow part of the roof fluctuates up and down in a "w" shape, the stress curve of the upper surrounding rock sinks slowly, and the coal pillars and filling bodies are alternately loaded during the staged mining process to jointly limit the movement of the overlying strata. The similar simulation test results showed that the roof has no structural damage, the roof cracks are not obvious, and the overlying strata control effect is good. On site tests showed that the CMCB mining method can effectively limit the movement of the overlying rock in the stope, control the surface subsidence of the ecological park, and increase the recovery rate of coal resources. It can provide a reference for the development of coal resources and ecological protection in a fragile environment. [ABSTRACT FROM AUTHOR]

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