Numerical simulation of roof cavings in several Kuzbass mines using finite-difference continuum damage mechanics approach.

An essential stage of mine design is an estimation of the steps of the first and periodic roof caving in longwall mines. Generally, this is carried out using the field experience and can be much enhanced by numerical simulation. In this work, the finite-difference method was applied coupled with the continuum damage mechanics (CDM) approach to simulate the stress-strain evolution of the rock mass with the underground opening during coal extraction. The steps and stages of roof caving were estimated relying on the numerical simulation data, and they were compared with the field data from several operating mines in the south of the Kuznetsk Basin, Russia. The dependence of the first roof caving step in simulation linearly correlates with field data. The results correspond to the actual roofs of longwall panels of the flat-dipping coal seams and the average rate of face advancement is approximately 5 m/day.