Post-mining ecosystem reconstruction.

ABSTRACT

The global decade of restoration brings into sharp focus the need to rehabilitate lands damaged by mining, to provide safe, stable, and productive landscapes. For the majority of mines, the required final land use is some form of natural, semi-natural or managed ecosystem, such as agriculture, aquaculture or forestry. Mining activities lead to new highly altered landscapes that require rehabilitation. These comprise various on-land stores of waste material and mined land itself. The repair of damaged ecosystems is described by many terms including restoration, rehabilitation, revegetation, ecological restoration, and reclamation. These terms overlap in meaning, have regional biases, and all fall short of what is really required ecosystem reconstruction. This requires a highly multidisciplinary approach drawing on many disciplines including geotechnical engineering, social science, soil science, law, hydrology, botany, geology, pollination biology, financial planning, alongside ecology. Ideally, mine rehabilitation should be progressive, start early in the life of the mine, and employ a strict regime of characterising and tracking waste materials for use in creating safe and stable post-mining landscapes. These actions will limit risks and optimise outcomes, especially when waste materials contain toxic metals or have high levels of acidity, alkalinity or salinity. Some mine sites are appropriate for the restoration of native ecosystems and biodiversity that existed pre-mining, but many, including landscape features created from waste materials, are not. Criteria for successful land rehabilitation are complex, multivariate, and highly contingent on the agreed final land use. Future advances in mine rehabilitation include the use of geomorphic landscape design and emerging thinking on cradle-to-cradle mining. This primer will discuss the complex factors that need to be considered in ecosystem reconstruction after mining and outlines approaches for optimising land rehabilitation outcomes.