## 5 Conclusions  
The study was conducted based on a reused roadway in a fully mechanized coalface with large mining height, which located in Sihe coal mine. The roadway deformation  
Figure 17: Roadway deformation curves before and after grouting. (**a**) Floor-to-roof convergency; (**b**) Two sides’ convergency; (**c**) Roof subsidence; (**d**) Floor heave.  
characteristics and forced mechanism were analyzed by field monitoring and numerical simulation, and then the reasonable grouting opportunities and technological parameters were correspondingly determined and validated by using self-developed inorganic double-fluid grouting material. The conclusions are summarized as follows:  
1. The roadway deformation was significantly affected by the lateral abutment pressure of the coalface during the first mining operation, which is characterized by lagging stable deformation and means a permanent deformation is achieved only after the coalface has advanced and passed a long distance. The deformation range during the first mining can be divided into initial deformation, violent deformation and plateaued deformation stages.
2. The roadway deformation is significantly affected by the leading abutment pressure of the coalface during the second mining operation, which is characterized by cease-lessly increasing deformation and means that the deformation becomes more and more severe with the advancing of the coalface. The deformation range during the second mining can be divided into initial deformation, slow deformation and violent deformation stages.
3. The grouting operation of the reused roadway ought to be conducted twice. The first grouting opportunity was suggested to be in the front part of the plateaued deformation stage during the first mining operation because the roadway damage had become stable basically at this stage. The second grouting opportunity was suggested in the slow deformation stage during the second mining operation because the gradually developed damage cracks provide the possibility for large-area grouting.
4. The grouting operation has greatly improved the broken surrounding rock of the reused roadway and reduced its deformation dramatically. However, the grouting is difficult to be conducted in several seriously damaged areas, in which the chemical materials could be used to form a surface-integrity layer that can seal the surface crack channels quickly. Some additional roadway repairs and reinforcements such as bolt or cable supports and so on are still be necessary for parts of severely damaged roads.  
L.Z.: Formal analysis, Methodology, Writing--original draft; Z.C.: Supervision, Writing--review & editing; R.P.: Supervision, Writing--review & editing; T.W.: Software; L.W.: Data curation; D.L.: Data curation. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP) (Grant No. 2019 QZKK0904), the National Natural Science Foundation of China (Grant No. 41972296) and the Fundamental Research Funds for the Central Universities (Grant No. 2022 YSMT05).  
The authors wish to gratefully acknowledge the mine management and co-workers in Sihe coal mine of Jincheng Coal mining group for their help during the field studies. Special thanks should be expressed to [PERSON] in Henan polytechnic university. The authors would like to thank the editors and the anonymous reviewers who presented critical and constructive comments for the improvement of this paper.  
The authors declare that they have no competing interest.