Report on the Managing Impacts of Deep-seA reSource exploitation (MIDAS) workshop on environmental management of deep-sea mining

Recent years have seen an upsurge in interest in mining in the world’s deep oceans, in areas beyond national jurisdiction. Such mining activity has the potential to cause environmental impacts over large areas. As contractors plan to move from exploration to exploitation activities it is important to develop guidance to ensure that these activities are managed in a way that is as environmentally sustainable as possible. This paper presents the outcomes of an international workshop on environmental management for deep-sea mining (DSM). The workshop presented protocols for environmental management, which were tested using a comprehensive polymetallic nodule mining scenario developed with industry input. The workshop started by presenting a framework for environmental management of deep-sea mining, which introduced the use of a conceptual model as a method of storing and updating environmental data and the synthesis of that data throughout the project. The second session focused on the incorporation of the precautionary approach and adaptive management into the framework. Two discussion sessions were held to discuss Environmental Impact Assessment (EIA) in the context of the scenario: the first considered scoping and screening EIAs, while the second reviewed the full EIA assessment. Subsequent discussion focussed on environmental management at the regional scale. This concentrated on the Regional Environmental Assessment (REA) - including its purpose, the scale and scope, and practicalities - and the assignment of protected areas as an approach for regional environmental management. Use of a scenario as a basis for the evaluation of protocols on the environmental management of DSM was novel amongst workshops, facilitating focussed discussion despite the high uncertainty surrounding DSM activities. The results of these discussions are summarised in the paper.