Evolution of the Fractured Zone Above a Coal Face with a Large Mining Height: A Case Study of the Dahuangshan Coalmine, China

The characteristic of the distribution and evolution of the fractured zone has important guiding significance for gas drainage design. In this paper, the 2ZW11 face of the Dahuangshan coal mine was chosen as an engineering example, and the evolution of the fractured zone was analysed using physical and numerical simulations. The results showed that in the vertical direction, the heights of the fractured zone and the caved zone tended to be stable after the face advanced to 200 m. The heights of the two zones drawn from the physical and numerical simulations were supported by the field test. The traditional empirical formula may not be appropriate for predicting the heights of the two zones of working faces with large mining heights. In the horizontal direction, the bed-separated ratio of the overburden strata above the face position was slightly higher than that of the overburden strata above the open-off cut position. Finally, a high-level drainage was designed and undertaken in the 2ZW11 face.