FLSmidth Roymec has supplied several long, curved, overland conveyors. The Zibulo Overland Conveyor is the longest single flight overland conveyor on the African continent. It is one of the longest single flight overland conveyors in the world. It features 3 horizontal curves and several convex and concave vertical curves. The high vertical lift (176m) of CV001 combined with the very long length of 15.9km for CV004 necessitated comprehensive static and dynamic analysis of the entire system.

Static analysis produces steady state running belt tension and power consumption for all material loading conditions and also accounts for temperature influences. Dynamic analysis determines belt tensions and power demand during the non-stationary cycles of operating the conveyor such as starting and stopping. This is required to simulate all motor and brake (or capstan) control functions and integrates their independent control methods with the elastic response of the system. The main objective being to develop control strategies and dynamic tuning methods to limit shockwave forces and belt line displacement to acceptable levels using drive inertia tuning and other methods.

Dynamic analyses utilise a two dimensional wave theory to study time dependant transmission of large local force and displacement disturbances along the belt. The belt is mathematically modelled as a series of elastic springs and masses that deform along the belt’s axis. Rheological laws determine the joints between the springs. Damaging shock waves and large local belt displacement can be resolved, which cannot be determined through static body analysis.

The Zibulo belt conveyors have been analysed for a variety of probable load cases and ambient conditions. FLSmidth Roymec thus had to consider a variety of friction conditions and seasonal temperature variations to ensure an energy-efficient and cost-effective design.