Evaluation of Results Relevant to Environmental Considerations of Polymetallic Nodule Mining Based on the German ATESEPP Project

Abstract

Abstract Realizing a need for increased general knowledge of the deep sea for environmental impact assessments related to the permanent storage of waste products and mining of metal resources, the German Bundesministerium für Bildung und Forschung has funded targeted research in the deep sea for more than ten years. The research was conducted in an area of the southeast Pacific Ocean close to and within a German mining claim, in order to accomodate the interests of German deep-sea polymetallic nodule mining enterprises and the developing mining code of the Preparatory Commission for the International Seabed Authority and the International Tribunal for the Law of the Sea. The "TUSCH (abbreviation for 'Tiefsee-Umweltschutz' = deep-sea environmental protection) Research Association" which includes members from various university and governmental institutions was involved in the ATESEPP (Effects of Technical Interventions into the Ecosystem of the Deep Sea in the Southeast Pacific Ocean) Project between 1996 and 1998. Geotechnical, sedimentological, geochemical, hydrographic, numerical modelling and ecological studies relevant to environmental impact assessment studies of polymetallic nodule mining were undertaken. Since general oceanographic knowledge of the deep sea is rather limited, these various projects also increased our general understanding of this region of the world ocean. This paper describes the potential impacts of mining processes on the seafloor and the near-bottom water layer as well as on bathyal and abyssal pelagic zones which will receive processing water, sediment and abraded nodule fines (tailings) discharged after nodule transport to the mining vessel at the ocean surface. The TUSCH Research Association defined various recommendations to keep the unavoidable impacts to a minimum. Introduction The ATESEPP (Effects of Technical Interventions into the Ecosystem of the Deep Sea in the Southeast Pacific Ocean) research project was aimed at providing a contribution to environmental impact assessments on the consequences of deep sea exploitation. Industrial interests have been increasingly directed towards this remotest of spaces on Earth during the last five decades and at least two uses the ocean depths are still being actively discussed, namely:permanent deposition of waste materials in the deep sea, (including the discharge of oil and gas drilling muds), andmining of metalliferous resources from the deep seabed. Both of these types of anthropogenic activity involve large-scale material transport, and the associated environmental impacts are unpredictable and not well assessed for all potential uses of the deep sea. The more severe disturbances of the marine environment are to be expected in conjunction with commercial mining which has also experienced greater engineering interest and is technically more advanced than deposition of waste material. Consequently, the TUSCH Research Association decided to investigate and characterize the effects of large-scale deep-sea activities by studying the impacts of polymetallic nodule mining, although commercial exploitation may not start for another two to three decades. Between 1985 and 1993, German companies and research institutions funded by the Ministry for Research and Technology were occupied with the development of mining techniques, and a mining test (prepilot mining test, PPMT) was planned for the early 90s.