Thomas, R, Bagnall, L & Fayyaz, A 2025, 'BHP Olympic Dam tailings storage facilities closure trials: a comprehensive approach 
to cover system field trial design and construction', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-14, https://doi.org/10.36487/ACG_repo/2515_71
(https://papers.acg.uwa.edu.au/p/2515_71_Thomas/)
Abstract: The Olympic Dam (OD) mine, located in the hot desert region of South Australia, Australia, is a copper-uranium-gold-silver mine in operation since 1988. Waste (tailings) from processing activities is stored across six onsite tailings storage facilities (TSFs), of which TSF 1-3 is inactive and require studies to inform final closure design. To achieve OD mine closure objectives, TSF 1-3 is to be closed with a cover system that minimises long-term maintenance and monitoring and ensures all risks are mitigated in the long term (10,000 years). Closure of the TSFs is contingent on meeting BHP and regulatory requirements by building the closure knowledge base through field trials and testing to adequately inform the final landform. This paper is the case study of the OD mine TSF 1-3 closure trials.
Through a series of extensive technical studies, social engagements and field investigations, cover system field trials have been designed and developed to inform final closure design and construction. This collaboration of subject matter experts, engineering service providers, stakeholders and regulators over 18 months has resulted in a robust suite of field trials that includes:
The primary and satellite trials are constructed on the TSF tailings surface with locally sourced construction material. Industry standard monitoring instrumentation is installed and integrated with existing infrastructure to measure and record field parameters. Close collaboration between all stakeholders and contractors, including the Responsible Tailings Facilities Engineer and Tailings Engineer of Record, ensures risks have been identified and mitigation measures put in place prior to and during construction. Outcomes from field trials will be used to increase certainty in the design and construction of the optimised final closure landform and inform the closure plan. 

Keywords: TSF closure, closure knowledge base, closure field trials, case studies, lessons learned