Abstract：Based on a separation dataset collected from a comprehensive underground monitoring in a coal mine in Australia，this paper presents the theoretical and analytical work on the roof separation characteristics，propagation and mechanisms of laminated weak strata of longwall roadway associated with different mining activities including stages of heading development，time-dependent，and longwall extraction. Analytical result indicates that roof separation and propagation are strongly related to different stages of mining activities，such as stress concentration and re-distribution in the stages of development and extraction and roof rock degradation and soften in the stage of time-dependent, and each stage involves different separation characteristics and mechanisms. The monitoring data also suggested that the major separation originated almost uniformly with the formation of opening from the roof surface up to 6 m upwards，and then two separation zones were formed in both lower roof strata in coal and upper roof strata in mudstone respectively. The two separation zones subsequently emerged gradually，and the merged separation zone covered from roof surface up to 6 m which is two times of the heading height. The results indicate that the mechanical characteristics of individual roof layers such as weak claystone layers，water effect on mudstone layers and the interface between the layers，as well as the levels of vertical and horizontal stress in pre- and post- stages of mining activities are important factors involved in roof separation mechanisms and control roof separation and propagation process.
