Development of a remote control rock bolting system for narrow seam hard rock mines

Abstract

An estimated 90 percent of South Africa’s gold-bearing reefs are less than 1 m thick Joughin (1976). A large mineral resource therefore lies in seams that are becoming increasingly uneconomic to extract because of the grade dilution caused by raising the mining height to suit currently available mechanized mining equipment Harper (2008). A similar situation applies to platinum resources. Historically in SA, mining of these narrow seams has been carried out by labour intensive methods, with little equipment beyond hand-operated rock drills. However, the arduous and hazardous work environment is becoming increasingly unattractive to both the workforce and mine operators. Globally, major mining companies are striving to increase safety by removing workers from the immediate vicinity of the operations and increasing productivity by better integration of the phases of the regular mining cycle to reduce cycle times Lynch and White (2013). Attaining both objectives requires going beyond mechanization to high degrees of automation and/or remote control of equipment. These factors present a challenge to South African mine operators and their equipment suppliers as mechanization of the narrow seam, hard rock mining environment has proven difficult with scant success Pickering and Ebner (2006), and Harper (2008). This paper describes the development of a semi-automated, remote controlled rock bolting system for hard rock mines with a mining height of between 0.9 m and 1.2 m (ULP Project). The rock bolting system required development of fully mechanized, remote controlled rock bolting rig, novel rock bolts and a pumpable, fast-acting resin grout to secure the bolts. The introduction of systematic rock bolting has resulted in a decrease in rock-related accidents, but the many manual operations required in drill-steel and bolt handling in confined spaces and close proximity to high-powered equipment, has led to increased injuries (particularly hand injuries) to the rock bolting operators Makusha (2015). Remote-control equipment has the potential to mitigate such injuries. The rock bolter is one component of an equipment suite enabling full mechanization of rock breaking by blasting, clearing broken rock and rock support. Development started in 2012 and the bolting rig has been operating on a platinum mine since 2017. Deployment of further equipment suites is planned for 2019.