A group including the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) on Friday announced that the majority of rare earth elements retrieved from sediment collected from the seabed off Tokyo's Minami-Torishima Island were types that China dominates the production of.

On the day, the group announced the results of the analysis on the sediment, whose test excavation was conducted in February. According to the announcement, about 54% of the collected rare earth elements, by weight, are classified as heavy or medium, including yttrium, which is essential for producing high-tech products. Production of heavy and medium rare earth elements is concentrated in China.

The results are raising hopes for future domestic production of such rare earth elements and diversification of supply sources. Full-scale test excavations are set to begin in February of next year.

According to the announcement, yttrium, which is essential for semiconductor manufacturing, accounted for 29.9% of the collected rare earth elements.

Gadolinium, which is used in materials for controlling nuclear reactor operations, accounted for 4.9%, and dysprosium, which is used in electric vehicle motors, accounted for 4.6%.

Light rare earth elements, which are distributed relatively widely outside of China, accounted for about 46%, with neodymium -- known as a raw material for permanent magnets -- making up 18.4% of the total weight.

The group refrained from disclosing the concentration and total weight of rare earth elements contained in the sediment, saying it is insufficient to announce as data because the amount of sediment collected is limited.

The test excavation was conducted as part of a large-scale Cabinet Office research project called Cross-ministerial Strategic Innovation Promotion Program. It took place within Japan's exclusive economic zone off Minami-Torishima. JAMSTEC extended a pipe from its deep-sea drilling vessel Chikyu to retrieve about 50 metric tons of sediment from the seafloor at a depth of about 5,600 meters.

The group plans to retrieve about 350 metric tons of sediment per day during the full-scale test excavation scheduled for February 2027. They plan to compile a report by March 2028 after evaluating factors such as profitability.

The term rare earth elements refers to 17 metallic elements essential to cutting-edge industries, frequently called the "vitamins of industry." China accounts for about 70% of global mining output and about 90% of refining capacity, and Japan relies on China for 60% to 70% of its imports.

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This article is from The Yomiuri Shimbun. Neither Dow Jones Newswires, MarketWatch, Barron's nor The Wall Street Journal were involved in the creation of this content.

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July 24, 2026 04:51 ET (08:51 GMT)

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