Design of an Optimum Longwall Face for Improved Ground Control: a Review

Abstract

This paper presents a critical review of the various approaches for the selection of the optimum length of longwall face considering ground control and cost parameters. Various factors affecting the efficacy of roof control and their impact on the productivity of a mechanized longwall face have been identified. The outcome of the study has been used to assess the knowledge gap in existing know-how and exploring the possibility of developing a hybrid methodology for the design of techno-economical optimum length of face combining the experiences of ground control and production economics of such operations. The critical ground control parameters identified for the purpose include massiveness of the strata formation and abutment loading that creates severe roof convergence and cavity formation in the face area apart from uncontrolled goaf settlement. Such roof control difficulties not only lead to frequent production delays and stoppages of the face but also contribute to the increased cost of production and reduced face productivity. Establishing a field representative relationship between the face length and severity of roof weighting and its integration with the existing cost economics is proposed for the optimum selection of face length to ensure smoother face operation with consistent face productivity. © 2020, The Institution of Engineers (India).