Numerical Modelling Approach For Assessment Of Factor Of Safety Of Ribs In Continuous Miner Depillaring Panels – A Case Study Of Churcha Mine

Continuous miner (CM) technology is being adopted as a successful mass production technology for working coal seams by underground (UG) method in India. This technology is getting established as an ideal option to meet the objectives of the high output, productivity, and safety with a moderate level of investment. In UG coal mines, the success of the bord and pillar method of working largely depends on the depillaring operations, as the maximum coal recovery is achieved during these operations. CM panels in India, especially during depillaring operations, experience in numerous problems like premature collapses, overhanging roof, partial extraction in a panel, etc., as some of the significant parameters influencing the stability of UG structures are still not standardised. As such, there is an urgent need to have a better understanding of the behaviour of UG structures, overlying roof and sidewalls for efficient and effective designing of the depillaring operations with particular reference to geo-mining conditions. This paper deals with a brief review of the strata control problems faced in CM workings and study of stress distribution for assessing the optimum factor of safety (FOS) of the ribs in CM depillaring panels by using numerical modelling as a tool. This model can be applied for assessing the pattern in variation of FOS of the ribs in CM depillaring panels for safe extraction of coal or, alternatively, for designing the ribs in such panels by fixing the threshold limit of the FOS of ribs for a particular geo-mining condition.