Microseismic monitoring and hydro-mechanical-damage simulation of vertical-well hydraulic fracturing in extra-thick hard roof strata

• A novel integration of vertical-well hydraulic fracturing, microseismic monitoring, and hydro-mechanical-damage simulation was established for ultra-thick hard roof strata. • Field experiments demonstrated fracture propagation up to 300 m in length and 360 m in depth, consistent with in-situ stress conditions. • Microseismic monitoring confirmed effective suppression of high-energy seismic events during subsequent mining operations. • Hydro-mechanical-damage simulations quantitatively characterized energy dissipation and validated the effectiveness of seismic risk mitigation. • This study presents a scalable engineering strategy enabling safe and efficient coal production under complex geological conditions. This study focuses on the 63 up 06 fully mechanized longwall face in the No.6 mining area of Dongtan Coal Mine. To address seismic hazards induced by extra-thick hard roof strata during extraction, an integrated methodology combining ground vertical well hydraulic fracturing, microseismic monitoring, and numerical simulation was implemented. Microseismic monitoring revealed that the dominant fracture generated during fracturing propagated parallel to the maximum horizontal principal stress direction, extending approximately 270-300 m in length and penetrating to depths of 330-360 m, thereby achieving effective fragmentation of the target thick-hard stratum. During subsequent stress-relief mining operations, both the frequency of microseismic events and the occurrence of high-energy seismic events were significantly suppressed. Numerical simulations employing a hydro-mechanical-damage (HMD) coupling model quantitatively validated the energy dissipation effect of hydraulic fracturing on accumulated strain energy in the roof strata. Results demonstrate that ground vertical well hydraulic fracturing effectively mitigates mining-induced seismic risks, providing a technical reference for safe and efficient coal production under analogous geological conditions.