9:45 AM - 10:00 AM
[SCG48-04] Environmental impact assessment for the development of seafloor massive sulfides
Keywords:seafloor massive sulfides, environmental impact assessment, environmental investigation, environmental protection measures, environmental impact forecasting
International interest in marine mineral resources is growing, and technical studies are underway for development. Japan’s projects for the development of marine mineral resources are being promoted based on "The Basic Plan on Ocean Policy" and "The Plan on Ocean Energy and Mineral Resources Development”. The Japan Organization for Metals and Energy Security (JOGMEC) has been promoting projects for seafloor massive sulfides, and during the five-year period from FY 2008 to FY 2022, the third phase of the development project was carried out in the areas of resource assessment, environmental impact assessment, mining and pumping technology, and ore dressing and refining technology. Our presentation will outline the results of environmental impact assessment in the third phase of the project.
In the field of environmental impact assessment, environmental investigations, development of environmental impact forecasting methods, and environmental protection measures were conducted to contribute for mining seafloor massive sulfides in the future.
For the environmental investigation, baseline surveys were conducted on the physical environment, chemical properties of seawater and sediments, and species and quantity of living organisms around seafloor massive sulfides in the Okinawa and Izu-Ogasawara waters, which have different topography and current conditions, using baseline survey methodology developed in the second phase (FY 2013 - FY 2017). In addition, environmental investigations were conducted to confirm the applicability of the developed methodology and to understand the environmental characteristics of each site.
In the environmental impact forecasting, the particle tracking model developed by the second phase of the project was updated to reflect the flow field created based on publicly available data and detailed topographic data. In addition, the extent of diffusion of turbidity due to seafloor disturbance caused by mining and other activities, and the thickness of redeposition were calculated and evaluated. We also confirmed the applicability of the particle tracking model to waaters where no observational data on flow conditions near the seafloor have been obtained.
In the study of environmental protection measures, we conducted genetic analysis of organisms collected around seafloor massive sulfides in the Okinawa and Izu-Ogasawara waters to understand the genetic diversity and connectivity among major organism species, in addition to the data collected up to the second phase.
In the field of environmental impact assessment, environmental investigations, development of environmental impact forecasting methods, and environmental protection measures were conducted to contribute for mining seafloor massive sulfides in the future.
For the environmental investigation, baseline surveys were conducted on the physical environment, chemical properties of seawater and sediments, and species and quantity of living organisms around seafloor massive sulfides in the Okinawa and Izu-Ogasawara waters, which have different topography and current conditions, using baseline survey methodology developed in the second phase (FY 2013 - FY 2017). In addition, environmental investigations were conducted to confirm the applicability of the developed methodology and to understand the environmental characteristics of each site.
In the environmental impact forecasting, the particle tracking model developed by the second phase of the project was updated to reflect the flow field created based on publicly available data and detailed topographic data. In addition, the extent of diffusion of turbidity due to seafloor disturbance caused by mining and other activities, and the thickness of redeposition were calculated and evaluated. We also confirmed the applicability of the particle tracking model to waaters where no observational data on flow conditions near the seafloor have been obtained.
In the study of environmental protection measures, we conducted genetic analysis of organisms collected around seafloor massive sulfides in the Okinawa and Izu-Ogasawara waters to understand the genetic diversity and connectivity among major organism species, in addition to the data collected up to the second phase.