Development of a Strategy Around the Placement and Design of Temporary Bridges Spanning Mining Scars on an Opencast Strip Mine in South Africa Using Sound Rock/Soil Mechanics Practices
- DOI
- 10.2991/978-94-6463-258-3_46How to use a DOI?
- Keywords
- Mining; Opencast; Limit Equilibrium; Finite Element; Trigger action response plan
- Abstract
The pursuit of operational targets such as tonnage and grade can often outpace the rehabilitation rate. This tends to leave large areas of mined-out strips (also known as scars) that must be traversed to ensure the hauling distance is shortened. Therefore, the resource must be efficiently extracted without disregarding sound safety principles. A geotechnical strategy was developed and implemented to mitigate this risk at an opencast strip mine in South Africa. The protocol involved a visual observation checklist, safe declaration and inspection during operations, numerical modelling in the forms of limit equilibrium, finite element, settlement analysis and an inspection sheet for the rock engineering report for the construction of a temporary bridge.
The bridge constructed in the mentioned case study will need to support surface infrastructure such as temporary powerlines and will serve as a dual carriageway for haul trucks and a walkway for the dragline. Geotechnical challenges that had to be overcome included underground workings, spontaneous combustion, tension cracks along the high wall and pore water pressures at the base. The ramp parameters (dimensions) were established by mine planning, with various slope angles, safety berm distances, and water pressures simulated using limit equilibrium modelling (L.E.M), finite element modelling (F.E.M) and Settle3 programs. The finalized design was determined by looking at the factor of safety, probability of failure, the position of the safety berm, the amount of soft and hard waste material available and the establishment time. The proposed design was accepted at a 37° slope angle with safety berms placed 18 m from the crests of the bridge, and this would require a minimum of ~531 000 m3 of material.
The bridge was monitored throughout the construction process by regular inspections and using a monitoring and surveying radar. In conclusion, the temporary bridge enabled the mine to continue fast and safe production. The models were successfully used to construct a bridge that was used for medium-term transportation in an opencast mine.
- Copyright
- © 2023 The Author(s)
- Open Access
- Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.
Cite this article
TY - CONF AU - Yogendran Arunachellan PY - 2023 DA - 2023/11/08 TI - Development of a Strategy Around the Placement and Design of Temporary Bridges Spanning Mining Scars on an Opencast Strip Mine in South Africa Using Sound Rock/Soil Mechanics Practices BT - Proceedings of the Rocscience International Conference (RIC 2023) PB - Atlantis Press SP - 467 EP - 477 SN - 2589-4943 UR - https://doi.org/10.2991/978-94-6463-258-3_46 DO - 10.2991/978-94-6463-258-3_46 ID - Arunachellan2023 ER -