Integrated design criteria for evaluation of support performance and estimation of support capacity requirement for longwall workings

Abstract

This paper discusses an integrated design criteria for estimation of optimal support capacity requirement for longwall working in a given geo-mining conditions. The selection criteria have been obtained by analysing the numerical modelling results of roof caving and support performance during progressive mining in different longwall workings operated in various coalfields of India and integrating them with their field experiences. The results of extensive parametric studies has also been utilised to bridge the gap of understanding and to enable reliable decision making even in the complex conditions. A quantifiable objective function of support has been defined in terms of the maximum permissible face convergence gradient for effective roof control during progressive face advance. For a practically viable solution of the problem in case of en masse caving strata conditions, optimum capacity support fitted with rapid yield valve of suitable rating is advised considering the worst instance of dynamic loading during the progressive face advance. The design criteria can be used for reliable planning to enable safer and smooth working of longwall faces in static as well as dynamic loading conditions.