Japan is embarking on an ambitious effort to retrieve rare earth elements from the ocean floor as it seeks to loosen China’s grip over the metals vital to missiles, radar systems and drones.
A Japanese state-backed expedition announced this month that it had successfully retrieved mud rich with rare earths from a remote Pacific seabed 6,000m deep — deeper than Mount Fuji is tall.
Japan in 2011 discovered resources near Minamitorishima, an atoll 1,900km south–east of Tokyo that is part of the country’s exclusive economic zone. But efforts to extract the elements have gained newfound urgency after China last month announced tighter curbs on exports to Japan, including rare earths.
Japan is the biggest consumer of rare earths after China. Beijing dominates the supply chain for the strategic minerals, controlling 60 per cent of mining and more than 90 per cent of refining and magnet manufacturing.
China’s trading partners, including the US and EU, have accused Beijing of weaponising that position in trade disputes, and have ramped up efforts to secure their own supplies.
Japan has in the past been forced to diversify its supplies. Facing an unofficial Chinese embargo on rare earths in 2010 following a territorial dispute, Tokyo began providing financing for Australia’s Lynas and building stockpiles.
Such economic security efforts are likely to accelerate under Japanese Prime Minister Sanae Takaichi, a national security hawk who has hailed the deep-sea extraction test as the “first step towards the industrialisation of domestically produced rare earths”.
Following her landslide election victory this month, Takaichi told local radio that she intends to ask the US to join the Minamitorishima project when she meets President Donald Trump in March. “We want the US to participate and speed things up,” she said.
The Trump administration has also proposed a co-operative trade zone for critical minerals with partners including Japan and the EU.
Japan’s latest spat with Beijing was triggered by Takaichi’s remarks last year about a potential military response to a hypothetical invasion of Taiwan. China responded by banning exports of dual-use items destined for Japan’s military, raising fears that rare earth supplies could be cut off again.
Global interest has surged in the potential of seabed mining to help countries secure critical minerals used in electric vehicle batteries as well as defence industries.
Some experts have questioned the costs of commercial deep-sea mining, however, while environmental activists have raised concerns about the impact on marine ecology.
Japanese government officials and academics say deep-sea locations could compete with land-based mining projects because of the high concentration of rare earths — especially heavy elements such as dysprosium, yttrium and terbium, where China’s dominance is stronger.
Ocean deposits also lack the radioactive material almost always found with volcanic land-based rare earths, which accumulate due to their similar chemical composition.
Thomas Kruemmer, author of the Rare Earth Observer, said that Minamitorishima was “seriously in play”, as few other locations could provide Japan with the range of rare earths that it needs as quickly.
“This is the resource of last resort,” he said. “They have to do something very swiftly with a short timeline. It’s no longer about price and cost. It’s about ‘do you have it or not?’”
Suppliers and traders estimate that Japan’s auto companies hold enough rare earths and associated products to see them to the end of the year, although some estimates are more pessimistic.
Any large-scale extraction at Minamitorishima is unlikely to come online quickly enough to avert a short-term supply crunch, however.
Shoichi Ishii, the cabinet office official who has led the Minamitorishima programme for seven years, said that a large-scale trial — excavating 350 tonnes of mud per day — would begin early next year. This would allow experts to assess the economics of lifting the mud, dewatering it on the island and hauling the mudcake back to mainland Japan for refining and separation.
“Minamitorishima rare earths is one option for future supply,” he said. “After March 2028, it could become one procurement source and contribute to the supply chain.”
Others have questioned the viability of extracting rare earths under huge pressure and from almost twice the depth of the deepest offshore oil project — as well as the ¥40bn ($255mn) already spent on exploration.
David Merriman, research director at specialist consultancy Project Blue, said that “the technical challenges and cost of this type of extraction are likely to outweigh any advantages from lower radioactivity or the heavy rare earth elements assemblage in the deposit”.
Even if deep-sea mining extraction is feasible, Japan would need to create a new process to separate and refine the raw minerals and strengthen manufacturing of rare earth magnets.
“It looks good as a diplomatic communication. The Japanese government tries to present Minamitorishima to the Chinese government as a big supply possibility,” said one industry executive involved in government plans.
“But in reality, it’s 6,000m deep and has a high exploration cost — it’s still more like an academic thing.”
