Designing for success: applying ecological criteria to restoration at BHP Beenup, Australia

Authors: Meney, K; Pantelic, L Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_rep/1915_16_Meney

Cite As:
Meney, K & Pantelic, L 2019, 'Designing for success: applying ecological criteria to restoration at BHP Beenup, Australia', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 185-198, https://doi.org/10.36487/ACG_rep/1915_16_Meney



Abstract:
The former BHP Beenup titanium minerals operation is in the biodiverse Scott River region in southwest Western Australia and was closed prematurely in 1999 after only two years of operation. Significant modifications to the landscape (including deep dredging to 55 m, lime sand blending with the natural soils to mitigate acid generation) combined with limited previous knowledge of the recruitment biology of many of the plant species, created significant uncertainty as to the feasibility of restoring the site to near-natural communities. This paper covers two aspects of the closure process: (1) a novel planning approach undertaken for setting the end use and target ecosystems using a designed based philosophy informed by risk assessment, and (2) the assessment of restoration success using ecological completion criteria. In terms of planning and design, the geomorphic and biodiversity features of the regional landform types (dunes, plains, sumplands, damplands etc.) formed the basis of design of closure sites. These regional ecosystems were surveyed in detail to characterise the soils, hydrology and vegetation of each major feature, with these ecological relationships then used to develop rehabilitation design criteria. Artificial landforms (deep pools created by dredging) were modified into lakes via void infilling and the creation of extensive shallow shorelines to generate a more naturalistic final shape. The focus on ecosystem design enabled revegetation to be tailored to the specific vegetation communities that best matched the reconstructed landforms; this significantly reduced seed wastage and increased the probability of success. As far as we are aware, it is the first project of this scale in Australia that has successfully created a functional range of wetland types similar to the surrounding natural wetlands. In terms of performance assessment, a detailed and prescriptive set of restoration and completion criteria were developed to enable a greater certainty of outcomes and enabled quantitative measurements of restoration success. The incorporation of sustainability and resilience, which are global indices of success used in ecological restoration projects outside of mining, were applied here to guide both the approach to restoration (so as to enable the site to adapt to changing climates and unpredictable events) and to the measurement of success (completion criteria). This was one of the first instances globally to embed these ecological concepts as key success categories for rehabilitation. Fifteen years after restoration, 15 ecological communities and more than 251 plant species have been successfully restored, including many conservation-listed species. The project achieved regulatory sign off against rehabilitation completion criteria in 2018 and is one of the few ‘ecologically designed’ post-mining landscapes globally.

Keywords: completion criteria, ecological restoration, end use planning, post-mined restored landscapes, wetland restoration, habitat creation, mine rehabilitation

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