Analysis of Vietnam coal mining pressure under competent strata using field measurement

Tóm tắt

This paper presents an analysis of Vietnam coal mining pressure under competent roof strata. Using classical ground pressure theories, the pressure law around longwall mining from setup entry to first strata caving and cyclic strata caving is strongly confirmed to follow pressure arch, voussoir beam and cantilever beam theories, respectively. Through analysis of shield pressure and shield convergence from a typical longwall mining under competent strata in Vietnam, the study clearly demonstrates the pressure law caused by progressive mining. The pressure change is proved to have a close relationship with roof strata movement and classical pressure theories. The pressure magnitude increases significantly and decreases rapidly when competent roof strata rupture. The difference in pressure and piston displacement between front leg and rear leg is an indicator for the stability of coal face and roof. The shield behaviours at T-junction are found to be less severe than those at the mid-panel width. The study proposes solutions to improving shield capability by increasing maximum support force and using multi-level face guard. The results from this study assist mining engineers in Vietnam in better understanding ground pressure on coal face and properly designing face support. The sustainable mining under unfavourable conditions can be better achieved for the national coal industry