Plumbing Seafloor Wealth

For the past decade, the mining industry has argued that the ocean floor is an essential frontier for precious metals needed in the batteries used in cell phones and laptops. As companies eye the best patches of ocean to search for the precious sulfides and nodules, widely dubbed “truffles of the ocean,” the waters near the Saya de Malha Bank—a submerged plateau the size of Switzerland in the Indian Ocean between Mauritius and Seychelles—have emerged as an attractive target. 

^{Text: Ian Urbina, Maya Martin, Joe Galvin, Susan Ryan, and Austin Brush – Editors at The Outlaw Ocean Project.}

Most of the Bank is too shallow to be a likely candidate for such mining. But some of the waters surrounding the Bank, in particular those outside the seagrass area on the broader Mascarene Plateau, reach depths over 9,000 feet and are well suited for mining. This is part of why several companies have already signed long-term exploration contracts to mine the area for precious metals, among them titanium, nickel, and cobalt.

Bulldozers on the seabed

To vacuum up the treasured nodules requires industrial extraction by massive excavators. Typically 30 times the weight of regular bulldozers, these machines are lifted by cranes over the sides of ships, then lowered miles underwater, where they drive along the sea floor, suctioning up the rocks, crushing them and sending a slurry of pulverized nodules and seabed sediments  through a series of pipes to the vessel above. After separating out the minerals, the mining  ships then pipe back overboard the processed waters, sediment, and mining “fines,” which are the small particles of the ground up nodule ore.

In 1987, studies in the Mascarene Basin, an area of the Indian Ocean that includes the Saya de Mahla Bank, found deposits possibly containing cobalt over an area of about 4,500 square miles. South Korea holds a contract from the International Seabed Authority, the international agency that regulates seabed mining, to explore hydrothermal vents on the Central Indian Ridge, about 250 miles east of Saya de Malha. This contract began in 2014 and will expire in 2029, and explorations in the area are already underway. India and Germany also hold exploration contracts for an area about 800 miles southeast of the Saya de Mahla Bank. 

Catastrophic consequences

All of this activity could be disastrous for the Bank’s ecosystem, according to ocean researchers. Mining and exploration activity will raise sediments from the ocean floor, reducing the seagrass’s access to the sunlight it depends on. Sediment clouds from mining can travel hundreds or even thousands of miles, potentially disrupting the entire mid-water food web and affecting important species such as tuna. 

The ocean floor itself is also slow to recover from mining activity. In 2022, scientists dispatched an underwater drone off the coast of Charleston, South Carolina, and found that tracks were still visible from a deep-seabed mining test that had been completed there half a century ago, according to a report by the Post and Courier, a daily newspaper. The areas between the tracks were devoid of fish, sponges, or nodules. Research published in 2023 found that a year after test seabed mining disturbed the ocean floor in Japanese waters, the density of fish, crustaceans, and jellyfish in nearby areas was cut in half.

‘Race between countries’

Proponents of deep-seabed mining stress a growing need for these resources. In 2020, the World Bank estimated that the global production of minerals like cobalt and lithium would have to be increased by over 450 percent by 2050 to meet the growing demand for clean energy technology. “It’s a race between countries to overtake one another in emerging and prime technologies,” says Arvin Boolell, Mauritius’ former foreign minister, adding that with such resources being used up on land, “the seabed is seen as the next frontier.” 

However, skeptics of the industry contend that battery technology is changing so quickly that the batteries used in the near future will be different from those that are used now. They also say that companies can rely on recovering and recycling used batteries. Other critics see the mining as a ponzi scheme of sorts that is meant to draw venture capital investment, but in fact has little real chance to make money in the long term. These skeptics say that due to the long transport distances and corrosive and unpredictable conditions at sea, the cost of mining nodules offshore will far outstrip the price of doing so on land. Furthermore, many of the largest car and tech companies have publicly stated that they are not interested in minerals from the deep sea. Better product design, recycling and reuse of metals already in circulation, urban mining, and other ‘circular’ economy initiatives can vastly reduce the need for new sources of metals, said Matthew Gianni, co-founder of the Deep Sea Conservation Coalition.

In July 2024, a group of ocean researchers filed a complaint with the US Securities and Exchange Commission alleging that The Metals Company, the biggest seabed mining stakeholder, had misled investors and regulators. More recently, The Metals Company, has begun pivoting away from a focus on batteries, and instead claims the metals are needed for missiles and military purposes. 

Some politicians in Mauritius are eager to take advantage of the financial opportunity that seabed mining appears to represent. In 2021, Mauritius hosted a workshop with the African Union and Norad, the Norwegian Agency for Developmental Cooperation, to explore seabed mining prospects. Government officials in Mauritius and Seychelles have said they’re taking a “precautionary” approach to deep-seabed mining, but are still moving forward with pursuing resources in their waters despite the warnings of ecological catastrophe. In September 2024, the two countries agreed to a deal to initiate oil exploration in and around the Saya de Malha Bank, a region they jointly manage.

Scepticism is growing

Around the world, skepticism about this type of mining has increased. Over 30 countries called for a moratorium or a precautionary pause on deep-seabed mining, according to the Deep Sea Conservation Coalition, a collective of non-governmental organizations and policy institutes that works to counter threats to the deep sea. 

In 2021, Greenpeace, a member of the conservation coalition, chose the Saya de Malha Bank as the location for the first ever underwater protest of deep-seabed mining. As part of that protest, Shaama Sandooyea, a 24-year-old marine biologist from Mauritius, dove into the Bank’s shallow waters with a sign reading “Youth Strike for Climate.” She had a simple point to make: that the pursuit of minerals from the seafloor, without understanding the consequences, was not the route to a green transition. She said: “Seagrasses have been underestimated for a long time now.” 

Cover photo: Nodules on seafloor. Black, potato-sized polymetallic nodules scattered on the seafloor in 2019 drew prospectors for their cobalt, nickel, copper, and manganese. Credit: Southeastern U.S. Deep-sea Exploration/Office of Ocean Exploration and Research/NOAA