# Study on Surface Damage Induced by High Heavy Layer Movement and Mining-Induced Earthquakes
## 5 Conclusions  
1. By applying the medium-thick layer theory to analyze the fracture movement of the heavy conglomerate layer overlying the 7202 working face, it was determined that the fracture movement of this heavy conglomerate layer is the driving force behind strong mining tremors. The analysis results align well with actual mining and detection data, confirming that the historically largest mining tremor event at the 7202 working face on 24 May 2022 was triggered by the initial fracture of the heavy conglomerate layer above the working face.
2. Numerical simulation studies reveal that during the surface damage induced by the movement of the heavy layer, the primary factor is the bending subsidence of the heavy layer itself, while the secondary factor is the heavy layer-type mining-induced earthquakes, which exacerbate surface damage by intensifying the movement of rock layer. As the heavy layer subsides, the rocks fracture and expand due to their bulking effect, increasing porosity. Mining-induced earthquakes compress these pores, enhancing the compactness of the broken rocks and increasing subsidence. After a mining-induced earthquake, the vertical displacement is most significant directly above the epicenter and decreases progressively toward the sides, indicating that the closer to the epicenter, the greater the impact.
3. Through field industrial trials, deep-hole roof pre-splitting blasting techniques was implemented at the 7202 working face of a mine in the Zaozhuang mining area, causing deformation and fracturing of the lower rock layer. Microseismic monitoring results show that after blasting, mining-induced earthquakes energy were mostly concentrated in the range of 10\({}^{1}\)-10\({}^{3}\) J, with no further occurrence of high-energy mining-induced earthquakes. The land subsidence rate slowed significantly, effectively reducing the frequency and intensity of heavy layer-type mining-induced earthquakes. This achieved the goal of mitigating surface damage induced by mining mining-induced earthquakes, providing strong support for the smooth progression of mining operations.
4. Beyond the specific conditions of the 7202 working face, the coupling mechanism of heavy layer fracturing and mining-induced earthquakes identified in this study may exhibit scale-dependent variations in other mining scenarios. For instance, in mineswith greater heavy layer thickness or deeper burial depths, the accumulated elastic energy during heavy layer fracturing could trigger higher-magnitude mining-induced earthquakes, potentially extending the surface damage range beyond the model-predicted values. Conversely, in shallow mining areas with thinner heavy layers, seismic energy may dissipate more rapidly, leading to reduced surface subsidence but increased risks of localized ground fissuring due to abrupt stress release.  
Conceptualization, [PERSON] and [PERSON]; methodology, Z.M.; software, [PERSON] and J.C.; validation, M.S., [PERSON] and C.J.; formal analysis, J.L.; investigation, J.J.; resources, Z.M.; data curation, J.C.; writing--original draft preparation, J.J.; writing--review and editing, Z.M.; visualization, Z.M.; supervision, Z.M.; project administration, Z.M.; funding acquisition, Z.M. All authors have read and agreed to the published version of the manuscript.  
The authors gratefully acknowledge financial support for this work provided by the National Natural Science Foundation of China (52274147, 52227901, 52474270). We also extend our thanks to the financial support for this work provided by the National Key R&D Program of China (2024 YFC3013802).  
Not applicable.  
The data used to support the findings of this study are available from the corresponding author upon request.  
The authors would like to thank the peer reviewers and editors for their valuable comments and suggestions, which have greatly improved this manuscript presentation.  
The authors declare no conflict of interest.