Japan's exclusive economic zone sports polymetallic nodules, which would support domestic battery mineral requirements for decades.

While the worldwide debate for and against harvesting critical minerals from international waters rages on, Japanese researchers have discovered their own massive mineral resource in the Pacific and are free to do as they please with it.

"Polymetallic nodules" (also known as manganese nodules) are essentially concentric layers of iron and manganese, additionally formed with various amounts of nickel, copper and cobalt around a small core of ocean detritus. The combination is tailor-made for battery chemistry needs.

The nodules are formed by the slow accretion of minerals from seawater. Polymetallic nodules occur with the greatest abundance on vast, undisturbed seafloors and are estimated to have an incredibly slow growth rate of less than four millimeters per million years.

Deposits of the battery metals nodules have been identified in the north-central Pacific Ocean, the Peruvian basin in the southeast Pacific, and the Indian Ocean – the most promising being between the Hawaii Islands and Central America in the equatorial Pacific Ocean.

Japanese nodule discovery

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Japanese researchers have discovered polymetallic nodules rich in battery metals off Japan's easternmost island.

Japanese researchers at the University of Tokyo and the Nippon Foundation now say they have discovered their own swathe of sea bottom rich with these lumpy concentrations in waters off Japan's easternmost island in the Pacific Ocean.

The research team surveyed more than 100 locations from April through June at an abyssal depth of 5,500 meters in Japan's exclusive economic zone off Minamitorishima Island, discovering an area with an estimated 230 million tons of manganese nodules covering the seabed.

Analysis of the nodules showed that in addition to manganese, they are mainly composed of iron, cobalt and nickel, with the amount of cobalt alone estimated at about 610,000 tons, equivalent to 75 years of Japan's annual consumption, and nickel at some 740,000 tons, worth about 11 years.

The university and foundation announced further plans to launch a large-scale test project to harvest the nodules as early as next year, followed by a joint venture in 2026 with multiple Japanese companies for processing.

Though many countries are deep into explorations of a similar nature, and the regulations and science of eco-friendly deep-sea extraction are still under development, this will be the first time that such a large-scale project will be launched in Japan.

Kato Yasuhiro, University of Tokyo professor and the director of Chiba Institute of Technology's Ocean Resources Research Center for Next Generation, said, "The most important thing is to make sure we do not burden the ocean environment, while presenting data that will be convincing."