For the past decade, the mining industry has argued that the ocean floor is an essential frontier for rare-earth 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 have emerged as an attractive target.
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. Consequently, several companies have already signed long-term exploration contracts to mine for precious metals including titanium, nickel, and cobalt in these waters.
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 seafloor, suctioning up the rocks, crushing them and sending a slurry of pulverized nodules and seabed sediments from between two-and-a-half and four miles undersea 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” (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 Malha 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 Malha Bank.
This industry activity on the seafloor will 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 is 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.
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,” Arvin Boolell, Mauritius’ former foreign minister, said, 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 now are not going to look like those used in the near future. 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. “There is massive investment now being put into developing batteries that don’t use these metals at all.” 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 an argument about batteries and instead claimed the metals are needed for missiles and military purposes.
Still, the poorer countries nearest to the Saya de Malha Bank continue to weigh their options. In 2021, Mauritius hosted a workshop with the African Union and Norad, the Norwegian agency for developmental cooperation, to look into seabed mining prospects. Government officials in Mauritius and Seychelles have said they’re taking a “precautionary” approach to deep sea mining, but are still moving forward with pursuing resources in their waters despite the warnings of ecological catastrophe. And in September 2024, the countries agreed to a deal to initiate oil exploration in and around the Saya de Malha Bank, a region they jointly manage.
Elsewhere, skepticism about this type of mining has increased. Over thirty countries called for a moratorium or a precautionary pause on deep seabed mining, according to the Deep Sea Conservation Coalition, a collective of NGOs 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.
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.”