Assessment of support capacity requirement for longwall working under difficult caving strata conditions

Abstract

Reliable assessment of caving behavior of strata and support capacity requirement has been an issue of great demand for reducing the strata control risk while planning of longwall workings specially in difficult to cave strata conditions. This paper describes the findings of an integrated modeling approach for assessment of roof cavability and estimation of optimal support capacity for longwall workings in a given geo-mining condition. A numerical modeling approach is described for assessing the progressive caving behavior of strata and performance of a hydraulic powered roof support in a given geo-mining and strata condition. The modeling approach for support selection is suggested for regular as well as en masse caving conditions integrating the results of numerical modeling and field observation of 23 longwall panels worked in different coalfields of India. A mathematical approach is used to assess the effect of dynamic loading due to en masse caving and to estimate the design requirement of rapid yield valve. The modeling results of a case study of Churcha mine, a mining site well known for its difficult caving strata characteristics in Sonhat coalfield of India is also described. © ISRM International Symposium on Rock Mechanics, SINOROCK 2009.