No abstract

Environmental impact assessment (EIA) and mine closure planning became formally integrated in Western Australia in 2011 when amendments to the Mining Act 1978 resulted in the requirement of a mine closure plan (MCP) to be submitted by proponents along with their EIA documents. This procedural innovation aimed to force early consideration of mine closure in line with international best practice and raise the level of closure planning compliance. Internationally, it is generally held that early closure planning will reduce costs and improve closure outcomes thereby reducing financial, environmental and social liabilities. This paper presents the results of the first study to explore the integration of EIA and mine closure planning in Western Australia and consider the extent to which such integration facilitates effective MCPs at the project approval stage. The opinions of twelve experienced EIA and/or mine closure professionals, representing regulators and proponents alike, were obtained from semi-structured interviews. Thematic analysis used both top down and bottom up approaches to identify recurring themes and novel concepts. Overall both regulators and proponents were found to be strongly supportive of the integration of EIA and the potential of early planning to improve mine closure outcomes, particularly with regard to the identification and reduction of risk. However, opinions were divided about the influence of integration on the effectiveness of early MCP or if the current Western Australian 'Guidelines for Preparing Mine Closure Plans' are capable of delivering effective early MCP. The responses suggest that although the current regulatory framework exists to drive integration that could enable effective MCP at the project assessment and approval stage, the most important factor is the motivation of key facilitators to pursue good outcomes. Opportunities to enhance the current framework lie in increasing transparency, expanding aspects of the guidance and ensuring enforcement of the commitments made in mine closure plans.

Closure cost estimation tools such as the publicly available Standardized Reclamation Cost Estimator (SRCE) are widely used to determine closure cost estimates for a variety of purposes. The SRCE was developed to provide a robust, defensible calculator for mine closure financial assurance by the State of Nevada, USA, and has been used internationally for financial assurance (FA) cost estimates, life-of-mine (LOM) and provision for environmental rehabilitation (PER), and for internal closure cost estimates.Minimising the liability of closure costs is increasingly important for mine planners, as experience dealing with mature mine sites has led to a better understanding of the magnitude of actual closure costs, and as companies seek to reduce ongoing liabilities associated with unrehabilitated land. In this context, Gold Fields Ltd has been working with the added functionality of the revised SRCE (v2.0) in relation to its St Ives operations to repurpose the closure cost model to facilitate real-time planning and management of mine closure. Specifically, the flexibility of the SRCE has been used at St Ives to analyse closure options. This has provided the benefit of reducing long-term closure costs by adapting short-term mine plans to accommodate the extended view of the mine life.