Significant wear in orepasses particularly in the brow and chute areas is proportional to the tonnage throughput with increased wear associated with running orepasses empty. During planned shutdowns it may be necessary to isolate maintenance crews from objects falling from orepasses. In the last 15 years grout orepass plugs that can later be easily removed have been poured above chute maintenance areas. These provide protection from high energy impact and isolating workers from the hazard. Construction and removal methods will be briefly explained. Since it is not feasible to investigate the problem of orepass plug impact response using full-scale experimental studies, this paper presents a combined three-stage approach that includes: 1. High-precision impact testing of reduced-scale models of orepass plugs. 2. High-fidelity physics-based numerical model calibration using experimental data. 3. Full-scale modelling of mine orepass plugs using calibrated material models. To calibrate numerical models, three 1 m diameter steel pipes filled with Tekseal high yield foaming grout were tested with falfing steel projectiles of different shape using the High-Capacity Impact Testing Facility at the University of Wollongong. Impact tests provided data on the depth of penetration and size of the ci6ters formed by the projectiles. Numerical models were calibrated by optimiSing the material parameters and modelling techniques to match with the experimental results. . Full-scale numerical models of orepass plugs were de veloped for typical orepass dimensions and subjected to impact events by falling rock projectiles. The proposed approach has allowed investigating energy absorbing characteristics of orepass plugs to further predict and increase understanding of their capacity to withstand high-speed impacts by large fa lling projectiles. This research will enable better understanding of orepass plug performance during high energy events and provide f urther engineering definition to mitigate risk to orepass maintenance personnel.
Available at: http://works.bepress.com/aremennikov/89/