In 2008, Xstrata Zinc launched a project to investigate the best ways to cover waste rock facilities at Black Star Open Cut mine. We have committed $1 million to the project over five years.

The first phase of the project will determine how much water enters waste rock facilities, using mathematical models and experiments on waste rock test plots. We constructed plots with cover of  varying thickness and compaction, and measured the moisture levels within the plots using a series of sensors.

The second phase will assess how well different types and densities of vegetation will grow on waste rock cover systems, and the extent to which vegetation cover takes up water falling onto the cover. This phase will be conducted as part of a PhD study being coordinated by the University of Queensland’s Centre for Mined Land Rehabilitation.

Together, the two parts of the project will provide accurate data about the amount of water that enters and passes through waste rock, so we can model the longterm effectiveness of different cover systems. The results of the study will reduce the risk of acid rock drainage at Black Star Open Cut mine and our other sites, and may save us money if it is found that cover thickness can be reduced.