Behaviour of Rope Guided Conveyances
Abstract
Most of the rock hoisting shafts developed recently in Australia have used rope guides rather than fixed steel guides. Rope guides offer advantages such as lower capital cost , lower maintenance costs and reduced construction times. However, the design of such systems is commonly based on what are appropriately described as 'industry rules of thumb'. The rules prescribe the static clearances required around he conveyances, tensioning applied to guide ropes and the minimum factor of safety for the guide ropes. However, they do not support the designer with a fundamental appreciation of the factors affecting the performance of rope guided systems.
Factors that affect conveyance lateral motion such as ventilation airflow, shaft depth, number, size and layout of guided ropes, conveyance velocity, payload etc. are not adequately addressed in the rules. Hence a new design methodology that accounts for these factors and leads to consistent designs with predictable performance is required.
This paper describes the results of field performance tests and a simulation model that considers the fundamental physics of the rope guided system. The model considers loading due to coriolis effect, aerodynamic effects and hoist rope torque. It permits the influence of all critical design parameters - guide rope size, tensioning layout etc. to be evaluated. The field measurements of clearance were undertaken on a newly commissioned rope guided shaft. Clearances were measured using a scanning laser and low cost inertial sensors.
Further rope guided skip field performance tests and comparisons with simulation results are advocated. The simulation and field test work are seen as essential steps in the effort to develop a technically sound approach to predicting the behaviour of rope guided systems.