The role of erosion models to benchmark stable post-mining landform designs

Authors: Nicolson, L; Hancock, G; Loch, R; Purtill, J Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_52

Cite As:
Nicolson, L, Hancock, G, Loch, R & Purtill, J 2026, 'The role of erosion models to benchmark stable post-mining landform designs', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-9, https://doi.org/10.36487/ACG_repo/2615_52



Abstract:
Robust landform design increases the likelihood of establishing a stable landform. Final landform design requires clear, well-defined objectives aimed at ensuring erosional stability, particularly by reducing rill formation and eliminating gully erosion. Erosion modelling provides a powerful way to test and compare landform design options. This requires a competent understanding of the underlying hydrological and sediment transport processes used by the specific model. This knowledge must then be combined with an understanding of soil physical functions and erosional processes along with site-specific information regarding material properties, climate setting, the receiving environment and post-mining land use. Model selection is a critical element, and the required complexity and accuracy of the modelling study are related to site risks. The model must be suited to the task required of it and supported by laboratory and field data. Site-specific parameters should be developed and are preferred over generic parameters. The model selected must have been tested and validated in a relevant context. In developing leading practice advice on erosion modelling, we identified that appropriate target erosion rates are crucial for modelling purposes. Gully erosion is a critical failure point for landform stability; exposure of underlying contaminants is not acceptable, and rills are the precursor to gullies. These principles inform the target rate for the modelling study. Target erosion rates are useful for modelling purposes, but any erosion rate is unacceptable if it leads to exposure of hostile materials and impacts to receiving environments in the final landscape. Designing a landform to avoid rill development will establish the benchmark for a stable landform. Provided the landform is constructed as per the design and achieves other interrelated objectives such as necessary rates of vegetation establishment, armouring of the surface and/or appropriate water management strategies, there will be greater confidence that design objectives can be achieved and sustained post rehabilitation.

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