Determination of Most Suitable Working Height of Powered Roof Support Considering Roof Stresses

Аннотация

In order to meet the increasing demand for coal, longwalls having large working heights up to 7.3 m are being operated worlwide. As the working heights increase, the load-bearing capacities of powered roof supports used at such longwalls are to be raised too. From a powered roof support it is expected that it safely bears the roof loads and transmits them to the footwall at different working heights. This article presents the results of numerical analyses on roof stresses at different longwall working heights. In order to determine the most suitable longwall working height, average stress distributions that occur on roof and gob zones are calculated for different longwall working heights. For this purpose, numerical models are built up and the procedure is applied to a real-life underground coal mine. Six distinct longwalls are modeled considering rock mass properties and working heights. In conclusion, the most suitable longwall working height for the mine under study is determined considering stresses occurring on roof strata and the gob zone.