Japan Recovers Deep-Sea Mud Containing Rare Earths Near Minamitori Island

Chikyu Deep-Sea Mining Mission Near Minamitori Island

Deep beneath the western Pacific, a government-backed marine vessel has pulled off what engineers and resource planners call a historic technical milestone. Operating at depths of roughly 5,600 meters (18,372 feet), the government-backed mining vessel Chikyu successfully completed a month-long mission near Minamitori Island, located about 1,900 kilometers (1,180 miles) southeast of Tokyo. The expedition achieved the world’s first successful continuous recovery of rare earth-bearing seabed mud from a depth of about 6 km. The expedition was part of a Cabinet Office project launched in fiscal 2018.

Laboratory Analysis of Rare Earth Elements

Medium and heavy rare earth elements accounted for about 54% of the rare earth content in deep-sea mud recovered off a remote Pacific island. Light rare earths, including neodymium, accounted for the remaining 46%, Kyodo News reported. The Japan Agency for Marine-Earth Science and Technology said rare earth elements extracted from seabed mud samples consisted of about 54% medium and heavy rare earths, including yttrium, gadolinium and dysprosium. Among the heavy elements identified were yttrium, gadolinium, and dysprosium. Yttrium serves critical roles in aerospace, energy, and semiconductor applications. Gadolinium is used in magnetic resonance imaging and other high-tech products. Dysprosium acts as an essential component in high-performance magnets for electric vehicles.

Project leader Shoichi Ishii of the Cabinet Office stated that it was extremely valuable for them to see yttrium especially, as its value had been soaring rapidly in the global market.

China Export Controls and Japanese Trade Policies

The urgency behind Japan’s offshore exploration ties directly to shifting geopolitical trade policies, bolstering its push to secure domestic supplies of critical minerals as China tightens export controls. Beijing imposed export controls on some heavy rare earths and related magnets in April 2025 before tightening restrictions on shipments to Japan in January and twice more the following month. Relations between the two countries deteriorated last year after Prime Minister Sanae Takaichi’s comments about how Japan might respond to a crisis involving Taiwan prompted Beijing to restrict exports of dual-use goods, including rare earths, Kyodo said.

University of Tokyo and Nippon Foundation Resource Estimates

By securing an independent supply of critical minerals used in defense equipment, electric vehicles, and advanced technologies, Tokyo aims to insulate its manufacturing base from foreign supply shocks. However, Japan’s government did not disclose the size of the rare earth deposit or the concentration of material in the recovered mud. Officials said the limited duration and geographic scope of the sampling program provided insufficient data for a broader resource estimate. The agency did not disclose the total amount of rare earth elements recovered from the samples. In 2024, researchers from the University of Tokyo and the Nippon Foundation had already identified over 200 million tonnes of manganese nodules rich in battery metals in the Pacific Ocean, highlighting vast resource potential at depths around 5,500 meters. A separate survey by the University of Tokyo and the Nippon Foundation estimated the seabed nodules contain approximately 610,000 tonnes of cobalt—enough for 75 years of Japan’s consumption—and 740,000 tonnes of nickel, covering 11 years of domestic demand.

Project Timeline and Commercial Trials Scheduled for 2027

JAMSTEC’s research vessel Chikyu collected about 50 metric tons of seabed mud from a depth of about 5,600 meters during January and February. The findings will pave the way for a full-scale mining test in the same area for about a month beginning in February. Beginning in February 2027, Japan plans a new month-long mining trial in the same waters targeting production of 350 tonnes of mud a day. The team plans to collect about 350 metric tons of mud a day for about a month beginning in February 2027. The material will be dewatered on Minamitori Island, about 1,900 km southeast of Tokyo, before being shipped to the mainland for separation, refining and smelting tests. The pilot program is designed to determine whether the offshore resource can support commercial rare earth production and reduce Japan’s dependence on imported supplies. Economic viability remains a major challenge because personnel and equipment must be transported to the remote island by air and other means. Kazushige Kikuchi, project manager at the Japan Agency for Marine-Earth Science and Technology, told Reuters that the trial was expected to verify the feasibility of domestic rare earth production. The government plans to evaluate the costs and feasibility of commercial production by March 2028. A comprehensive assessment of the project’s commercial potential is due by March 2028. The government will later assess the costs and benefits of industrialization by March 2028.