Publication Details

Drew, J. (2001). The application of coupled bolts in managing adverse horizontal stress conditions at Oaky Creek coal. 3rd International Underground Coal Conference (pp. 1-16).


Development drivage of Tailgate 21 commenced in May 2000. Difficult roof conditions associated with the splitting of the G ply coal away from the immediate seam into the roof were anticipated. 4.1m Coupled Bolts were considered to be a potentially cheaper and more effective reinforcement system than long tendon cables for these conditions. Coupled bolts have been used very effectively in similar conditions at Alliance Colliery. Coupled bolts were trialed for the first time at Oaky No. 1 between 18-19c/t TG21 where the interburden thickness between the roof and the G Ply seam split was between 1.4m and 4m. Indicators of slight horizontal stress (slight guttering) were observed in headings and cut throughs inbye of 10c/t. Horizontal stress conditions became significant inbye of 23c/t with buckling roof conditions occurring in cut throughs. Coupled bolts have been used in cut throughs to control roof deterioration. Significant instrumentation and analysis has been used to define deformation mechanisms and a number of different support systems have been trialed. This paper outlines the use of coupled bolts in TG21 at Oaky No.1.