U.S. and Japan Plan to Develop World's Deepest Seabed Rare Earth Mine to Challenge China's Supply Chain
Nashnova编辑部
The U.S. and Japan are working to develop a rare-earth deposit roughly 6 km beneath the ocean surface near Minamitorishima — the deepest seabed mine ever attempted. This means → both nations are trying to break China's decades-long monopoly on heavy rare earths at the source, but technical viability won't be clear until after 2028.
What is actually down there — and why does it matter?
Test samples released by Japan's Cabinet Office show the deposit holds large quantities of yttrium, gadolinium, and dysprosium — heavy rare earths that China dominates globally.
This means → these are not ordinary rare earths. They are the specific elements needed for permanent-magnet motors, military radar, and precision guidance — exactly the categories most exposed to China's export controls.
A joint U.S.-Japan statement calls the reserves sufficient for "hundreds of years" of industrial demand — a big number, but reserves ≠ recoverable output, and the gap at this depth could be enormous.
Six kilometers down — how hard is this technically?
The deposit sits roughly 6 km below the surface. The deepest offshore oil-and-gas drilling today reaches only about half that depth.
In plain terms = humanity's existing deep-sea engineering has never operated at this level. The entire technical frontier needs to be pushed roughly twice as far.
Water pressure at the site is about 600 times sea-level atmospheric pressure. Private-sector estimates put extraction costs at roughly 3× China's onshore mining costs, requiring over a decade and billions of dollars in investment.
Who is doing the work — and how far along is it?
All current work is led by Japan, which has mature deep-sea exploration capabilities.
On the U.S. side, several North American firms — including Houston-based Deep Reach Technology — have expressed interest, but talks remain at a very early stage.
This reflects a practical reality: Japan has the survey expertise, the U.S. has oil-and-gas drilling experience, and the project needs both — yet the partnership framework is far from formed.
What is China doing?
Bloomberg's analysis of commercial ship-tracking data shows a Chinese ocean survey vessel has conducted seabed mapping near Minamitorishima multiple times in recent years, operating right up to the boundary of Japan's exclusive economic zone.
This means → China is not just controlling rare-earth mining and processing on land; it is actively scouting its competitors' potential alternative sources.
Put simply = even if the U.S. and Japan begin extraction, China's geological intelligence on this deposit may be nearly as good as Japan's own.
Why is Japan pushing so hard?
Prime Minister Sanae Takaichi has positioned Minamitorishima as Japan's core strategy to break dependence on Chinese rare earths.
The immediate trigger: late last year, China restricted rare-earth exports to Japan, citing Takaichi's earlier remarks on Taiwan — sharply raising the project's political priority.
Her long-term growth strategy envisions mobilizing roughly $57 billion in public and private capital for deep-sea resource development by 2040, with Minamitorishima as the flagship.
Can this actually change the rare-earth map?
Hudson Institute senior fellow William Chou argues the project could help the U.S. and Japan build a complete "mine-to-magnet" rare-earth supply chain, weakening China's leverage.
But a commercialization roadmap won't take shape until 2028 at the earliest, and actual output is more than a decade beyond that.
In plain terms = China's control over heavy rare-earth supply faces no near-term disruption. Minamitorishima is a ten-year-plus play — whether it pays off depends on parallel breakthroughs in deep-sea technology and geopolitical alignment.
Content is for reference only, not financial advice.