Marten, R & Bagnall, C 2019, 'Engineering a path to relinquishment: an Australian case study in ecological conservation', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1477-1490, https://doi.org/10.36487/ACG_rep/1915_115_Marten
(https://papers.acg.uwa.edu.au/p/1915_115_Marten/)
Abstract: Achieving relinquishment of residual environmental and other liabilities post-closure poses a key challenge for mining and heavy industry alike. Since closure of the Newcastle Steelworks (Steelworks) in 1999, BHP has implemented a range of projects to remedy a legacy from 85 years of steelmaking. Of these projects, the five-year Hunter River Remediation Project (HRRP)—completed in 2012—has been the most substantial undertaking and represents the largest clean-up project of its kind completed in Australia. At its conclusion, and for the quality of its work, the HRRP was recipient of national environmental and engineering excellence awards.
In delivering the HRRP, BHP made a firm commitment to restoring areas impacted by the Steelworks whilst preventing as far as practical any new impacts arising from remediation works.
As part of the HRRP, the construction of a purpose-built, lined emplacement facility on former Steelworks land was required to dispose of over 800,000 m3 of cement-stabilised river sediment. Whilst on disturbed industrial land, the construction footprint of this facility extended over habitat of the endangered green and golden bell frog (Litoria aurea). This species had colonised ponded areas within the industrial site, perhaps after the cessation of Steelworks activities.
BHP’s response was to go back to ‘first principles’ to minimise its potential to cause impacts to this species. With no other feasible locations to receive this volume of treated sediment, BHP implemented a comprehensive process to re-assess its original emplacement facility design. This work ultimately conserved 90% of the local breeding habitat and, additionally, new habitat was created in nearby areas. BHP has recorded successive breeding events in the new habitat, contributing to a significant increase in the species’ local population. In addition to the ecological benefits, the facility redesign materially reduced the complexity and associated time frame and costs of the regulatory approvals needed to commence the major remediation works.
This paper will discuss the key aspects of BHP’s design and execution approach to minimise its ecological footprint whilst engineering a feasible path to the relinquishment of related liabilities.

Keywords: Newcastle Steelworks, Hunter River remediation project, green and golden bell frog, Litoria aurea, compensatory habitat program