Lourel, I, Todd, DJ & Liu, AY 2022, 'A step-by-step guide for evaluating the preferred closure scenarios using a hybrid options assessment model', in AB Fourie, M Tibbett & G Boggs (eds), Mine Closure 2022: Proceedings of the 15th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 503-512, https://doi.org/10.36487/ACG_repo/2215_35
(https://papers.acg.uwa.edu.au/p/2215_35_Lourel/)
Abstract: The achievement of optimal closure outcomes hinges on a robust planning and execution process. Closure planning should be an integral part of an asset’s lifecycle, with a formal, detailed planning process being initiated towards the end of operational cessation. Useful guidelines, case studies, and project delivery models exist to assist the closure planning process. While these provide a structured framework for addressing key elements of closure, they do not transcribe all circumstances, complexities, and decisions faced by an asset owner and impacted parties.
The ability to optimise closure execution diminishes once the preferred closure scenario is committed to by the appropriate decision-makers, with a subsequent escalation of change implementation cost over time. From a myriad of interdependent and sometimes conflicting requirements, variables and uncertainties, an asset owner must find a way to achieve a balanced scorecard while meeting its obligations and stakeholder expectations. To this aim, this paper presents a potential process map for determining the preferred closure scenarios, including instructional steps, a hybrid options assessment model, and examples for each component.
Prior assumptions should be verified through data gathering to fill knowledge gaps, establish context and baseline knowledge, and define the relevant closure domains and work elements. With the necessary input of subject matter experts, technical practitioners and project stakeholders, a set of integrated trade-off studies can be carried out using multi-criteria analysis (MCA) to assess the merit and impact of key decisions under each closure scenario. Compatible options between trade-off studies can be linked up to form branches of a decision tree for each closure scenario, where preferences on possible decisions are revealed by the quantitative MCA scoring as well as qualitative ranking of the trade-off studies. Given the subjective nature of these assessments, different perspectives should be adequately considered/challenged, and the results tested through sensitivity analysis. The options selection process should be transparent, rigorous, defensible and well documented to form a robust basis for decisions that will have an enduring legacy.

Keywords: closure study methodology, closure scenarios, closure options, trade-off study, options assessment