Japan’s deep-sea drilling ship Chikyū sneaked out of Shimizu Port in Shizuoka prefecture on a gloomy January morning and headed southeast toward a tiny, sparsely populated island that most Japanese couldn’t find on a map. After arriving at Minami-Torishima five days later and traveling about 1,900 kilometers, it continued, in a sense, all the way to the ocean floor, which is almost six kilometers below the surface. What emerged was a dense, clay-like mud that contained rare earth elements that are essential to the global clean energy, electronics, and defense sectors.
During a mission that ended in early February 2026, the Chikyū collected 350 metric tonnes of this sediment rich in rare earth elements. Days before a widely anticipated general election, on February 2, the results were confirmed by Japan’s Cabinet Office and JAMSTEC. To be honest, the timing seemed intentional. Sanae Takaichi, the prime minister, ran in part on a platform of mineral security, criticizing Japan’s risky reliance on Chinese supply chains. In response to Takaichi’s comments regarding Taiwan and collective self-defense, China, for its part, tightened exports of vital minerals and dual-use goods to Japan beginning in late 2025 and continuing into January 2026. Like a political poster, the deep-sea announcement landed. Her coalition won a supermajority on February 8th, regardless of whether it was planned that way or just politically exploited.
Regardless of the politics surrounding it, the seabed discovery itself is real. According to preliminary estimates, the Minami-Torishima deposit, which was first discovered by JAMSTEC in 2013, may contain up to 16 million tonnes of rare earth oxides, making it one of the world’s three largest deposits of that kind. Using only the top ten meters of sediment, the most promising 102-square-kilometer section could produce 1.2 million tonnes of REE oxide on its own. If further investigation confirms that amount, it would be sufficient to meet the world’s needs for terbium, dysprosium, yttrium, and europium for many years. Centuries, perhaps. REE grades of up to 0.5 percent have been found in core samples, which is comparable to terrestrial mining operations that have been profitable for many years.
The formation process of this mud is what makes it geologically fascinating. This sediment accumulated slowly, almost patiently, in contrast to hydrothermal sulfide deposits or manganese nodules. Over long periods of time, fish-bone debris composed of biogenic calcium phosphate settled to the ocean floor, absorbing rare earth elements from the surrounding seawater. These elements were concentrated into thick, enriched layers by the region’s high biological activity and low sedimentation rates. REE-rich muds are now categorized by scientists as a fourth unique type of deep-sea mineral resource, which is a subtle but important recognition that humanity has discovered something it didn’t fully comprehend before.
It’s another matter entirely to get the mud to the surface. It is not easily scraped or dredged and has the consistency of soft clay. Japanese engineers have been developing what they refer to as a “subsea factory”—equipment on the seafloor that agitates the sediment, blends it with seawater, grinds it into fine particles, and then pumps the resulting slurry up through reinforced riser pipes. It is truly difficult to build pipes that can withstand constant abrasion, mechanical stress, and nearly six kilometers of ocean pressure. Additionally, preliminary research has shown that the deeper sediment layers are softer than anticipated, which significantly complicates the engineering. At the commercial level, none of this has been resolved.
Experts in deep-sea mining, some of whom were interviewed by researchers in Japan prior to this report, believe that the government’s enthusiasm slightly exceeds the technical reality. Extraction would need to increase from 350 tonnes per day to at least 3,500 tonnes per day in order for this operation to be profitable. That is a tenfold increase, and there is currently no infrastructure in place to support it. It took the Chikyū five days to travel from a major port to Minami-Torishima due to its extreme remoteness. There are still unanswered logistical issues with moving thousands of tons of mud back to the mainland and refining it once it gets there. At the moment, Japan’s refining infrastructure isn’t designed to handle this amount or type of material.
There are also gaps in the legal system. In order to give the government more authority over seabed resources within the EEZ, Japan amended its Mining Act in 2022 to include rare earth minerals. However, the Act does not protect the environment; rather, it deals with mining rights. Seabed extraction is just not covered by Japan’s Environmental Impact Assessment Act, which has been in effect since 1997. We still don’t really know what happens to the surrounding marine ecosystem when thousands of tonnes of sediment are disturbed every day.
It’s difficult to ignore how much depends on what is currently only a proof-of-concept. The January 2026 mission proved that it is physically possible to reach and recover rare-earth-rich mud from extremely deep depths. That’s not nothing; rather, it’s a major technological achievement that puts Japan ahead of all other nations in the development of this kind of deep-sea extraction capability. A complete commercial feasibility report is anticipated by March 2028, and trial operations at 350 tonnes per day are scheduled for January 2027 if the lab analysis of the recovered samples produces positive results.
It remains genuinely unclear whether the numbers ultimately work and whether that timeline holds. It is evident that Japan has determined that this is the direction it must take. Tokyo seems unwilling to wait for a more agreeable resolution after witnessing China weaponize mineral exports twice in fifteen years, once in 2010 over the Senkaku dispute and again in late 2025. Japan is speculating that it has discovered one in a deposit of old fish bones and slowly accumulated ocean chemistry six thousand meters below the Pacific.
