Developing ecological completion criteria to measure the success of forest and woodland establishment on rehabilitated mines in Australia

Over the last 20 years, mining companies throughout Australia have increasingly adopted an objective of establishing sustainable native ecosystems following mining. A significant area of risk associated with mine closure is the question of completion criteria for native ecosystem rehabilitation - what standards will regulators and the community accept as part of an overall mine closure plan, which if met, will result in lease relinquishment? Two examples from mines located in forest and woodland habitat in different parts of Australia illustrate how companies have adopted an innovative approach to the development of ecological completion criteria. Alcoa World Alumina Australia mines bauxite in the jarrah forest of south-western Australia. Shallow mining (~4 m) occurs in isolated pods averaging 10 ha in size. The overall objective of rehabilitation is 'to restore a self-sustaining jarrah forest ecosystem, planned to enhance or maintain water, timber, recreation and conservation values'. Completion criteria were developed after extensive liaison with stakeholders. The criteria are assessed at five different stages, ranging from planning (prior to mining) to late (10-15 years). More than 25 years of research data enabled Alcoa to set criteria that include a range of biodiversity and ecosystem function measures. Wesfarmers Curragh Mine in central Queensland is located in a woodland environment. The open-cut coal mine produces large spoil areas that are reshaped and planted to an open woodland/grassland community. A recent study recommended completion criteria which state (in part) that 'The objective of rehabilitation following mining at Curragh is to establish a stable, self-sustaining native ecosystem that fulfils designated land uses including protection of water resources and nature conservation, and which.is similar in composition and function to that occurring in representative unmined reference sites'. Compared to those of Alcoa, the Curragh criteria reflect differences in the pre-mining environment, climate, and the mining operation. This paper describes the similar approach used to develop completion criteria at the two mines, and illustrates how the issue is being addressed in Australia