According to the Japan Agency for Marine-Earth Science and Technology, the discovery site is the deep sea floor from the eastern part to the southern part of the exclusive economic zone around Minamitorishima, with a depth of 5,500 to 5,800 meters.The estimated distribution area is about 4 square kilometers, which is almost half of the area of ​​Hokkaido.

　The manganese nodules on Minamitorishima are rich in not only manganese but also rare metals such as cobalt, nickel, copper and molybdenum, and base metals, and their distribution area overlaps with rare earth mud where rare earths (rare earths) in seawater are concentrated.Manganese nodules are thought to be spherical because seawater and seafloor components gather and move by being shaken by ocean currents.

　The research team conducted a sound wave survey of the seafloor in the waters around Minamitorishima and measured the reflected waves to identify the location where manganese nodules are likely to exist. In April 2016, a manned submersible research vehicle was put into the sea area to confirm the density of manganese nodules and to collect about 4 rocks.

　Since the water depth is too deep, an efficient method of raising it has not yet been established, but it is the first time that a large-scale manganese nodule has been found in Japan's exclusive economic zone, and future development is expected.

　Since the cobalt-rich crust of sedimentary rocks rich in rare metals and rare earths is distributed around the manganese nodules, the research team will analyze the composition of the manganese nodules and clarify their relevance.