Abstract

Multiple LHD systems controlled by a single operator have been demonstrated to be technically feasible by using a telecommand system to load and dump vehicles and an automatic guidance system to control travel between drawpoint and dump locations in separate production drifts. Prototype systems have been developed by several major mining companies. In this study, a discrete event model was constructed using the simulation language SLAM-II to analyse the queuing time losses inherent in both two and three vehicle systems. Queuing losses are shown to depend on both tramming distance and average travel speed (which takes into consideration haul route geometry). The study provides data to illustrate that, when evaluating the feasibility of implementing single operator -multiple vehicle underground haulage systems, labour cost savings must be carefully balanced against capital costs and revenue losses resulting from queuing. This is of particular relevance to mines in which single operator-multiple vehicle systems are being contemplated for relatively short haulage distances.