Prediction of caving behavior of strata and optimum rating of hydraulic powered support for longwall workings

A reliable prediction of the caving behavior of strata and support capacity requirement for longwall workings has always been a challenge for rock mechanics researchers and mine planning engineers. It is very important for successful planning and implementation of high capacity longwall projects to have proper selection of site and compatible roof supports, to ensure safe operation of longwall face especially in massive and difficult to cave strata conditions. This paper illustrates a numerical modeling based integrated approach for predicting the progressive caving behavior of strata and optimum capacity requirement of powered support for longwall working in a given geo-mining and strata condition. A set of design criteria for selection of optimal capacity support integrating the field experience and the numerical modeling results of longwall panels, operated in a widely varying strata conditions in different coalfields of India. Case studies of two typical longwall workings are presented to assess the caving behavior and support requirement for safe operation of longwall working under the site specific regular and en masse caving strata conditions.