Separation Characteristics And Mechanisms Of Laminated Composite Roof Strata Of Longwall Roadway Based On Geomechanical Characterization And Interpretation, With Special Reference To Daliu Colliery

Roadways play an important role in mine safety in production, it is an importantguarantee for the smooth conduct of the mining activity. Based on a separation datasetcollected from a comprehensive underground monitoring in a coal mine in Daliu,and numerical simulation using UDCE, this paper presents a theoretical and analyticalwork on the roof separation characteristics, propagation and mechanisms, associatedwith different mining activities, including stages of heading development,time-dependent, and longwall extraction. It is found that roof separation andpropagation are strongly related to different stages of mining activities, and each stageinvolves different separation characteristics and mechanisms.The monitoring data alsosuggested that the major separation initialed non-uniformly with the formation ofopening from the roof surface up to6m, mainly concentrated in the range ofthe roof surface up to3m, and then, with the expansion of the separation, there haveformed two larger range of separation area. Two separation zones were formed in bothlower roof strata in coal and upper roof strata in mudstone respectively. Furthermore,two separation zones emerged gradually with time elapsed, and the separation zonecovered from roof surface up to6m, which is two times of the heading height. Theresults indicate that the mechanical characteristics of individual roof layers, such asweak claystone layers, water effect; such as mudstone layers and the interfacebetween the layers, as well as the levels of vertical and horizontal stress before andafter each stage of mining activities are important factors involved in roof separationmechanisms and controls roof separation propagation process.