Keneally, J 2023, 'What can we learn from the process safety journey to improve our understanding of the closure challenges and cost estimate?', in B Abbasi, J Parshley, A Fourie & M Tibbett (eds), Mine Closure 2023: Proceedings of the 16th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2315_087
(https://papers.acg.uwa.edu.au/p/2315_087_Keneally/)
Abstract: Mine closure projects by their nature are complex as they exist within a broad system that straddles the geophysical, ecological, climatological and societal. The closure cost estimate is derived from a set of assumptions and a knowledge base that evolve over time. Many creeping increases in cost can occur as a result well before execution. 
A risk assessment is often completed in early closure planning stages to inform the closure cost estimate. Intangibles or externalities, like reputation, can be recognised and evaluated in non-financial terms. Technical and delivery assumptions can also be measured this way, or through a financial lens. These are critical to inform the closure planning scope, but can remain disconnected from the closure cost estimate only to be factored in at a later time. 
The process safety journey has been well documented since the Flixborough incident in 1974. The tangible nature of catastrophic process safety events has helped build a sense of urgency to proving an operation is safe, rather than assuming it is safe. Various quantitative risk assessment tools and techniques are utilised in process safety that have the explicit aim of demonstrating to leaders that the operation is safe, all of the time.
The immediacy of the closure challenge is highly influenced by time. This paper explores tools that are transferrable and adaptable from the process safety and supporting industries to closure risks. A more quantitative approach to understanding the closure challenges and the closure cost estimate can help build a more balanced sense of urgency. With this, scarce resources can be allocated to deliver the right work at the right time.

Keywords: estimating closure costs, risk, financing, process safety