Design and Performance of Protective Water Barrier Pillars for Underground Coal Mines in India—A Review

Abstract

A reliable design of protective water barrier pillars is critically essential for safe operation in underground mine workings. Different approaches are applied for the design of such barrier pillars, but none of them have ever evolved as a standard. This paper presents the outcome of a literature review covering various aspects of protective water barrier pillar design, including its hydro-mechanical modeling. Width/height (w/h) ratio, cover depth, water head, permeability, and discontinuities have been identified as the critical parameters influencing the performance of such protective pillars. For a given water head and the depth of cover, a lower w/h ratio of the pillar can result in an increased seepage from the pillars and inundation hazard in the worst condition. The review shows that in-depth research is required for an improved understanding of the mechanism of water flow and the failure of such pillars. This will not only help in assessing the adequacy of existing pillars but also in forming guidelines for the design of new protective pillars based on an updated knowledge base and improved understanding of the subject. © 2021, The Institution of Engineers (India).