Height of fractured zone inside overlying strata under high-intensity mining in China

The height of fractured zone (HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the high-intensity mining. The processes of overburden failure transfer (OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established. A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel (No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies’ result and empirical formulas’ result. The rationality and reliability of the theoretical method proposed is verified. Keywords: High-intensity mining, Overburden failure, Height of fractured zone, Overlying strata movement