Japan has identified a high concentration of valuable heavy rare earth elements in deep sea mud recovered from waters near the remote Pacific island of Minamitori, marking another step in its efforts to reduce dependence on Chinese critical mineral supplies.
The Japanese government said on Friday that analysis of rare earth rich mud collected earlier this year showed medium and heavy rare earth elements accounted for about 54% of the total rare earth content. However, officials did not disclose the overall size of the deposits, saying the limited scope and duration of sampling meant the available data was insufficient to estimate total reserves.
The samples were collected during a month long expedition in February by Japan’s scientific drilling vessel Chikyu near Minamitori Island, approximately 1,900 kilometres southeast of Tokyo. The mission marked the world’s first successful continuous recovery of rare earth bearing seabed mud from depths of around six kilometres beneath the ocean surface.
Strategic Push for Mineral Security
The project forms part of Japan’s broader strategy to strengthen supply chain security for critical minerals following tighter Chinese export restrictions on heavy rare earth elements and magnets, which are widely used in defence systems, electric vehicles, semiconductors and other advanced technologies.
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Researchers recovered approximately 50 metric tons of seabed mud during the expedition.
Analysis identified several strategically important rare earth elements, including yttrium, used in aerospace, semiconductor and energy technologies; gadolinium, widely used in medical imaging and other high technology applications; and dysprosium, a key component in high performance permanent magnets used in electric vehicle motors.
Commercial Mining Trial Planned
Japan plans to conduct a month long large scale mining trial in the same waters beginning in February 2027.
The trial aims to recover approximately 350 tons of seabed mud each day. The material will first be dewatered on Minamitori Island before being transported to mainland Japan for separation, refining and smelting tests.
The project will evaluate whether domestic deep sea rare earth production can become commercially viable. A comprehensive assessment of industrial scale production is expected by March 2028, according to Kazushige Kikuchi, project manager at the Japan Agency for Marine Earth Science and Technology, which operates the Chikyu research vessel.
China Remains Dominant Supplier
Japan’s exploration efforts come amid growing concern over China’s control of global rare earth supplies.
Beijing introduced export controls on several heavy rare earth elements and related magnets in April 2025 and later tightened restrictions on exports to Japan in January, followed by two additional rounds of measures the following month targeting major Japanese companies.
Rare earth elements are essential components in advanced manufacturing, including electric vehicles, renewable energy systems, military equipment, consumer electronics and semiconductor production.
Analysis
Japan’s latest findings highlight the growing strategic importance of securing independent supplies of critical minerals as geopolitical competition increasingly shapes global supply chains. Although the newly analysed deposits have yet to be proven commercially viable, the discovery strengthens Japan’s long term effort to reduce reliance on Chinese exports. If future mining trials demonstrate economic feasibility, deep sea resources could become an important pillar of Japan’s critical minerals strategy while encouraging other resource poor countries to accelerate investment in seabed mining technologies despite ongoing environmental concerns.
With information from Reuters.