Application of Pre-Tensioned Cable Bolting (Bulbed Type) at Adriyala Longwall Project

Abstract

High capacity longwall technology introduced at Adriyala longwall project with a rated capacity of 3.0Mt per annum. Huge machinery required to be installed in longwall face and gate roads. This machinery required wider gate roads of 5.2 to 5.5m widths. The immediate roof in gate roads is coal with thicknenss of 4.0mtr. Immediate roof consists of 2 clay bands of 0.3m and 0.7m thickness within the bolted and above the bolted horizon causing bed separation in the immediate roof, resulted in that, during development of gate roadways, 85% of roadways are good in condition, 15% of gate roads were observed with guttering, geological disturbances, water seepage, and in some areas horizontal stress effect is also noticed. While retreating of longwalls, major disturbances were observed in gallery ahead of the longwall face, and also in cut through galleries and adjacent gate roads subjected to abutment loading. To overcome the above issues, Pre-tensioned bulbed type cable bolting is introduced first time in India as secondary support in gate roads of longwall panel to ensure its stability over long period and also to eliminate standing support in gate roads ahead of the longwall face. In this paper, the installation and performance of bulbed type cable bolt is discussed in detail.