Longwall face stability index (LFSI): A novel approach for estimation of chock-shield pressure and face convergence

摘要

Several longwall faces in India have collapsed due to adverse geological conditions and/or inadequate capacity of powered supports. Thus it is imperative to access the capacity of a powered support and its interaction at longwall laces ol' varying geomining conditions in advance with lots of confidence. To achieve this, an index has been developed to ascertain the from leg pressure (FLP) of chock shield support and roof-to-floor convergence (RFC) at longwall faces. The index called 'Longwall Face Stability Index' (USD has been developed using statistics and Finite Dement Modelling (FEM). The front leg pressure (FLP) and roof-to-floor convergence (RFC) predicted from the LFSI are validated with the Held monitored data from two longwall panels. In this study, an attempt is also made to incorporate various gcomining condiiions into the finite element models typical of longwall mining practice. The index has taken into account the wide variations of gcomining parameters like thickness, young's modulus and friction angle of main roof (small, large), coal type (soft, hard), powered support capacity, and depth ol coal seam. Thus. LFSI can be thought of as an index representing combined ellect of roof type, geomining conditions and powered support capacity.