Accelerated corrosion investigations on mechanical hybrid rockbolt steel

The recent introduction in underground mines of mechanical hybrid rockbolts has been driven by efforts to eliminate the use of resin in heavily fractured ground. Mechanical hybrid rockbolts consist of a steel tendon mechanically anchored within a friction unit. Installation of mechanical hybrid rockbolts is percussion-driven by the rock drill and the mechanical anchor is subsequently activated using rotation. The bolt configuration and installation process overcome issues associated with hole closures and the use of resin. Recent work has focused on understanding the behaviour of the rockbolts under quasi-static and dynamic conditions but there is scant information on the anticipated performance in corrosive underground environments. This paper reports the results of a comprehensive accelerated corrosion investigation of the principal components of mechanical hybrid rockbolt, which can aid in establishing the long-term suitability of mechanical hybrid rockbolt in corrosive environments.