Rachel Standish

The development of acceptable and achievable completion criteria is a necessary part of mine closure planning and fundamental to the successful transition of mined land to a future use. Completion criteria have been defined in the mining context as agreed standards or levels of performance that indicate the success of rehabilitation and enable an operator to determine when its liability for an area will cease. Once achieved, they demonstrate to the mining company, regulators and other stakeholders that financial assurances and liabilities can be removed. Because of this important function it is imperative that completion criteria are effectively formulated to capture end-state goals, are accepted by all stakeholders and agreed by regulators and the proponent, are achievable, and can demonstrate this achievement through transparent and appropriate monitoring and documentation.

While considerable progress has been made in mine closure and rehabilitation planning in Western Australia, there remains a need to build capacity and understanding of how to best measure rehabilitation success and to set practical outcomes and measurable completion criteria, particularly with respect to environmental parameters. To address this gap, The Western Australian Biodiversity Science Institute (WABSI) has brought together leading experts, mining industry representatives and regulatory agencies to develop this report.

This report has two parts. The first part (Chapter 2) presents a new framework to help guide the decision-making process associated with completion criteria development. The second part (Chapters 3, 4 and 5) document current understanding and perspectives on completion criteria development. The framework is presented as a process consisting of six steps that enables the industry to demonstrate ability to support the agreed post-mining land use. Each step includes key considerations and guidance to inform the decision making and prioritisation process. The decision-making process should be captured when using the framework to develop site-specific criteria. Tools have been provided to support the recording and presentation of information to demonstrate the process used and application to a specific site. This common set of definitions, processes and methods will also help to reduce inconsistencies across regulators, mining companies and consultants.

The six steps are: 1. Selecting post-mining land uses; 2. Determining aspects and closure objectives; 3. Selecting references; 4. Selecting attributes and risk-based prioritisation; 5. Developing completion criteria; and 6. Monitoring. The remainder of the report (Chapters 3-5) supports the framework by documenting the current state of knowledge on completion criteria development in Western Australia. It provides the context and directions for users of this guide to consider, and learn from, when developing completion criteria and risk-based monitoring system development.