Simulation of the deformation of a stope support design

Abstract

Supported stope mining is one of the most common types of mining in the modern day gold mining industry. The excavated regions, where ore is extracted, are supported with a combination of roof-bolting, timber packs, backfill, timber props and mechanical prop technologies. In order to install a support system that will be able to absorb the energy released by the elastic movement of the surrounding rock mass and support the unstable hanging wall, it is necessary for the rock engineer to know how the individual types of support will react to different load conditions in order to design a safe support system. Current support systems are developed using knowledge from past experience and trial and error processes. These are expensive and time consuming methods that can possibly be improved and made more cost effective by using modern design techniques. A study was conducted to determine the feasibility of the application of Finite Element Modelling (FEM) to the deformation of a modern support unit under specified quasi-static and dynamic stope load conditions with the view to assist in the prediction of the operational performance of support units that cannot be experimentally tested due to a lack of test equipment, capabilities and facilities. The study was extended by investigating the theoretical possibility of buckling due to an impact load on the prop and the performance of the prop. To achieve this, a simulation was carried out using ANSYS™ transient structural software to determine whether it is possible to simulate the performance curve of a prop. Computerised methods were used to determine the possibility of failure due to buckling and the implications of buckling, if it occurs, on the performance of a specific support prop design. In summary this study proved that it is possible to simulate the performance curve of a friction prop design in order to compare the result obtained with the required performance, provided that the correct friction coefficients between prop mating surfaces are known. It also presents a methodology to investigate the theoretical effect of high velocity impact load on the buckling potential of a friction prop design and slender columns in general, which is highly applicable to these types of support. The methodologies used in this study can be applied to different designs of friction props, and possibly reduce the development costs and implementation time of these types of support units.