ID: 1823
Presenting Author: Chisato Murakami
Session: 537 - Mining Across Land, Sea, and Space: Understanding and Communicating Social Impacts
Status: pending
DORD examined the environmental impacts of turbid flow generated by the movement of collector vehicles in preparation for future test mining in exploration Contract Areas.
Deep Ocean Resources Development Co., Ltd. (DORD) has signed an exploration contract with the International Seabed Authority in the CCZ and carried out an environment impact assessment in preparation for future test mining activities. The assessment covers the full scope of operations including support vessel movements into the test mining area, collection tests and the deployment and retrieval of the collector vehicle. This study focuses specifically on the sediment plume generated by the collector vehicle, identified as the greatest impact. A simulation was conducted to model plume diffusion and near-field turbidity flow as the vehicle travelled across a 100 m x 900 m area. Among the causes of plume generation during nodule collection, the vehicle’s track was predicted to disturb more sediment than the jet-induced entrainment. It was also found that volume of plume generated is strongly influenced by the travelling speed and sediment settling behavior. It was estimated that most of the near-field suspended sediment is redeposited within approximately 1 km of the operating area, indicating a relatively localized impact. The results of this study will be incorporated into a comprehensive impact assessment that also considers other factors such as the hydrodynamic diffusion of small particles that do not fully settle, discharge plumes from lifted water, underwater noise, and the influence of the mining support vessel.
Chisato Murakami is a marine biologist specializing in invertebrate taxonomy. She earned her Ph D. at Kyoto University in 2003 and has been in charge of environmental surveys at DORD since 2018.
Coauthor 1: Keisuke Nishi