Three-dimensional (3D) Rockfall Assessment for Landbridge Reclamation

DOI

10.2991/978-94-6463-900-1_43How to use a DOI?

Keywords

Rock Fall; Barrier Assessment; 3D Modelling

Abstract

Reclamation of a large landbridge constructed from backfill material is required as part of the mine closure plan for an open pit mine in the Pilbara region of Western Australia. There is a risk that rock falls initiated during mining of the landbridge could affect an area located approximately 80-100 m from the landbridge slope toe. This paper presents a rock fall assessment that was undertaken to assess the rock fall hazard posed by mining of the landbridge.

The first stage of the assessment involved a series of rock fall field trials on a comparable slope to the landbridge. The aim of the trials was to collect an empirical dataset to support a calibration of rock fall modelling parameters. Rocks were dropped in the trials, of which the end points were surveyed and the distribution compared to existing rocks at the field trial slope toe. 2D and 3D back-analyses were undertaken using RocFall2 and RocFall3 from Rocscience. The model parameters were modified iteratively until the endpoint distribution achieved a good correlation with both the field trial and existing rocks. Benchmarking was also undertaken to compare to industry experience.

The second stage of the assessment comprised a series of predictive rock fall models aiming to quantify the potential for rock falls initiated from the landbridge ending in proximity of the exclusion zone. 3D analysis methods were considered more appropriate for the predictive modelling due to high variability in the site topography. The 3D analyses were undertaken utilising the field trial calibrated parameters to assess the risk of rock falls potentially affecting an area near the base of the landbridge. The initial modelling results were compared to the distribution of existing rocks on natural slope below the landbridge to further validate the parameter appropriateness and the predictive model results. Barrier analyses were undertaken to assess rock fall control options.

Copyright

© 2025 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.

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TY  - CONF
AU  - Michael Farmer
AU  - James Watton
AU  - Jan Janse Van Rensburg
AU  - Kim Le Roux
PY  - 2025
DA  - 2025/12/07
TI  - Three-dimensional (3D) Rockfall Assessment for Landbridge Reclamation
BT  - Proceedings of the Rocscience International Conference 2025 (RIC 2025)
PB  - Atlantis Press
SP  - 436
EP  - 445
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6463-900-1_43
DO  - 10.2991/978-94-6463-900-1_43
ID  - Farmer2025
ER  -