Mine Closure and Ecosystem Development ⎯ Alcan Gove Bauxite Mine, Northern Territory, Australia

Abstract

Closure is a critical phase of a mining operation since this is when the environmental effects of mining and rehabilitation works will be most stringently judged. Since the time scales required for biological community development and soil formation are long in comparison to mining operation life cycles - and to human life spans - it is normally only possible to demonstrate the early trajectories of these processes. However, favourable and predictable closure outcomes can usually be achieved by making early decisions on postmining land use, ensuring close integration of mining with incremental rehabilitation works and adequate monitoring. This assumes that a successful system of rehabilitation is available for the materials and environments involved and takes no account of threats or stressors. This paper defines the stages of early post-rehabilitation ecosystem and soil development on highly weathered soil materials at the Alcan Gove Mine using information derived from studies of selected sites from a 26-year chronosequence of sites and local native forest sites. Specifically, we seek to determine the stage at which a high probability of successful ongoing development may be credibly assumed in the absence of further management inputs of energy and materials and in relationship to potential external threats.