Estimating the environmental impact of deep-sea mining

Details

Supervisors

Hanert, Emmanuel ; Deleersnijder, Eric

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en mathématiques appliquées, à finalité spécialisée

Abstract

Deep-sea mining is currently a hot topic of debate as terrestrial mineral reserves are getting depleted and mineral demand keeps rising. Deep-sea mineral reserves exceed terrestrial reserves by millions of tons. Crucial minerals required for sustainable energy such as batteries and solar panels start to become sparse on land. However, deep-sea mining operations do not come without risks and might significantly impact abyssal ecosystems. In this study, we investigate the environmental impact of deep-sea mining activities. We are particularly interested in the extraction of polymetallic nodules in the Clarion Clipperton Zone. We evaluate how the sediment plumes generated by the collector vehicle might impact the local environment. We first develop and validate a 3D version of the multi-scale ocean model SLIM focused on the deep ocean circulation. We then couple this model with a Lagrangian sediment transport model to simulate the sediment plumes dispersal and settling. That allows us to estimate the extent of deposited sediment plumes for stationary and mobile sources, for different sediment release heights and for two types of sediments (sand and silt). Our results suggest that the area indirectly impacted by deep-sea mining activities, i.e. through the deposition of sediment plumes, is about 5 to 10 times larger than the area directly impacted by the passage of the harvesting vehicle. We hope that the conclusions of this study can help both private companies involved in deep-sea mining activities and international authorities who will have to manage these activities to make informed decisions to minimize the environmental impact while helping society to curb climate change.