A Novel Method for Predicting Movement and Damage of Overburden Caused by Shallow Coal Mining

Most prediction methods used to calculate mining-induced subsidence do not involve the formation of overburden, and therefore cannot explain the mechanism of fundamental rock strata movement. Due to the differences of the overburden's formation in different mining areas, to develop a feasible method for determining the movement of overburden is significant. This paper presents an original method for determining the movement of overburden, which is based on the key stratum theory and Mohr-Coulomb failure criteria. The mining-induced movement of overburden is described by two major theoretical models: the Analogous Funnel Model (AFM) and the Analogous Hyperbola Model (AHM). The theoretical predictions of movement boundary of overburden and surface subsidence are given in each model. The Distinct Element Method was used to assess the performance of the theoretical models using a case study of the Antaibao coal mine in Western China. The theoretical and numerical subsidence of the primary key stratum was validated by field measurements, most of which are in good agreement. The theoretical predictions of surface subsidence and the movement boundary of the overburden also match well with the numerical results during supercritical mining. The primary key stratum damages the least in the overlying strata in the Analogous Hyperbola Model.