As international trade tensions rise and nations across the globe scramble for critical mineral resources to protect national security and ensure a steady supply of strategic materials, miners are getting ready to venture into an uncharted territory.
World oceans hold enormous amounts of untapped mineral wealth featuring an abundance of ferromanganese nodules, base- and precious metal-rich sulphide deposits, cobalt-rich crusts and many others. Despite the major technological advancements and successful early attempts at deep-sea mining in the 1970s-1980s, the potential of this extraction method has mostly remained unrealised due to adequate supply from surface mines and higher costs associated with this type of resource exploitation.
However, the situation has changed significantly over the past 50 years. Ore grades are declining, bridging the cost gap between conventional mining and deep-water projects. The policy across the globe is shifting towards carbon neutrality which requires large investments in green energy technologies, and in turn creates a significant demand for battery metals. At the same time, countries and blocs around the world are increasingly concerned about their mineral sovereignty amid geopolitical tensions.
Thus, the ocean floor is now seen as another frontier to potentially secure critical mineral supplies. Such firms as The Metals Company, Impossible Metals and others are working tirelessly to claim the lucrative deep-ocean exploration and mining permits and gain a headstart in a critical metals race. But there is quite a hurdling to be done before the deep-sea mining is given a greenlight.
An ocean of resources
There are three major types of deep-sea resources. Polymetallic manganese nodules are found on a seabed at a depth of 4 - 6 km in concentrations of 11 - 15 kg per square meter, and they typically contain high grades of manganese, nickel, copper and cobalt. Seafloor massive sulphides are found at hydrothermal vents along mid-ocean ridges at depths of 1.5 - 3 km, and they are rich in valuable metals like copper, zinc, silver, and gold. In contrast, cobalt and manganese-rich crusts are found in shallower waters at depths of 0.8 - 2.4 km, and they also contain copper, nickel and trace amounts of battery and rare-earth metals.
Deep-sea mining diagram. Source: https://www.grida.no/resources/8156
Mining of these deposits may be achieved through different means and technologies. In the case of polymetallic nodules - which are currently the primary focus for deep-sea mining - mining vehicles would collect mineral deposits from the surface of the seabed, not unlike a tractor plowing a field, along with the top layers of sediment. The materials collected would then be piped up to a surface vessel for processing, and any waste, such as sediments and other organic materials, would be pumped back into the water.
Deep-sea polymetallic nodules in the Clarion–Clipperton Zone, Pacific Ocean
The Japan Oil, Gas and Metals National Corporation (JOGMEC) has been working toward developing seafloor polymetallic sulfide deposits. In 2017, it successfully tested continuous lifting of ore from the seabed in exclusive economic zone of Japan near Okinawa.
It is still unclear how the crusts can be mined at all in large volumes in the future. So far, only conceptual plans have been presented and laboratory experiments carried out. The concepts being worked on by engineers include caterpillar-like vehicles that peel the crusts away from the stone with a kind of chisel, and pump them to the ship at the surface through special hoses.
Even though deep-sea mining requires unconventional approaches, known seabed reserves may hold more valuable minerals than global land reserves. Some estimates suggest the global subsea metal tonnage to be around 250 trillion dry tons, which is almost 20 times more than 13 trillion tons found at land-based deposits. This is in part due to the vast expanse of the oceans which cover 70% of the planet's surface, and in part that terrestrial reserves have been significantly exploited and depleted.
Land and deep-sea resource comparison. Source: https://deepseamining.ac/opportunity_size
Cobalt-rich crusts dominate the subsea tonnage, and make up around 80% of the estimated total. Polymetallic nodules are only around 20% of the subsea total, but are still approximately 3.6 times the total terrestrial resources.
Deeper into the subject
Even though manganese nodules on the seabed were first discovered in the 1870s, the commercial interest in deep-sea resources only became apparent in 1960s. Amid this growing interest the UN General Assembly held discussions between 1973 and 1982 to study the issue, which eventually resulted in establishing the United Nations Convention on the Law of the Sea, often called "a constitution for the oceans." In addition to establishing a regulatory framework for marine cooperation, it established the International Seabed Authority (ISA) in 1994 to oversee the seabed mining in areas of the ocean beyond the limits of national jurisdiction. The new body was also tasked with issuing contracts for exploration and exploitation, as well as distributing some of the mining royalties.
So far, the ISA has issued a handful of exploitation contracts for the deep seabed, most in the Pacific Ocean, though no significant mining has yet taken place. But this may change in the foreseeable future - both from within and without.
On the one hand, ISA is on a tight schedule. A 1982 UN treaty requires establishing regulations to allow deep-sea mining, which ISA is tasked with, however, the deadline for the final decision has been postponed numerous times. As of today, the deadline is set to July this year. Meanwhile, some 2,000 points in the current draft regulations remain in dispute, and ISA will likely set a new deadline, possibly triggering legal challenges from mining companies, Bloomberg said in a report.
The recent change in ISA leadership and the new US administration can both influence the decision-making process in deep-sea mining regulations. A new secretary-general of the UN-affiliated organization calls for “transparent, inclusive and science-based governance,” while US President Donald Trump administration’s focus on securing critical minerals may spur a prompter action. The US hasn’t ratified the Law of the Sea treaty and isn’t a member of the ISA, but it participates in the organization’s meetings as an observer.
For now, ISA continues to deliberate over regulations amid global calls for a moratorium on deep sea mining. Scientists and environmentalists warn that industrial mining activities could wreak havoc on the ocean, a crucial carbon sink and home to rare and diverse species.
Abyssal terror
Just recently, a Canadian deep-sea mining firm The Metals Company focused on polymetallic nodule extraction in the Pacific has announced plans to apply for permits under existing U.S. mining code for deep-sea minerals, circumventing ISA’s authority and triggering a backlash from the UN-backed organization, environmentalist groups and diplomats alike.
ISA’s new secretary general Leticia Carvalho has expressed “deep concern” over the announcement, adding that “any unilateral action would constitute a violation of international law and directly undermine the fundamental principles of multilateralism.” Diplomats from more than 30 nations such as China, Russia, India, the United Kingdom, New Zealand, Indonesia, France, Argentina, Uganda and others have criticized a proposal that would defy the UN law on international waters.
Environmentalists followed suit, calling for an international moratorium on deep-sea mining after a move which was described as “a slap in the face to international cooperation.” Nature-protection groups are concerned about the consequences of mining activities in the ocean that are not well understood.
Admittedly, a recent study paints a bleak picture: the effects of a deep-sea mining test conducted in 1979 are still apparent today. Researchers have revisited a test site and found that the tracks of the 100-tonne machine that was sent down to the seabed are still visible, and that the impact of mining on some of the wildlife is ongoing.
“Forty-four years later, the mining tracks themselves look very similar to when they were first made, with an 8-metre-wide strip of seabed cleared of nodules and two large furrows in the seafloor where the machine passed,” a member of the expedition said.
The fact is that mineral-rich nodules laying on the bottom of the ocean have been part of the ecosystem for millennia, and the disturbance caused by industrial mining may destroy a delicate balance in the deep sea which to this day remains a sparsely studied region of our planet. In addition to the loss of biodiversity, industrial mining at sea may lead to such negative economic consequences as undermining fishing industry and jeopardizing food security.
The exploitation of seabed mineral resources is seen as a potential solution to the shortage of critical minerals necessary for the green energy transition. Counterintuitively, it may have an opposite effect on climate change, as microscopic organisms in seabed sediments play a significant role in sequestering carbon. Disturbing a sediment layer with robotic miners would re-suspend large portions of this carbon in the ocean which would, in turn, release it back into the atmosphere.
Back to the surface
Deep-ocean mineral deposits could make a significant contribution to future raw material supply as global metal demand grows, geopolitical challenges persist and land deposits deplete further.
The deep seafloor covers about 60% of the Earth's surface and after decades of ocean exploration, and as of 2009, only about 10% of it has been surveyed by ship-based sonar systems. At the same time, the European Commission estimates that as much as 10% of the world’s minerals could be mined at the ocean floor by 2030.
However, this natural environment is still all but inaccessible for humans, and we can only rely on technological advancements such as robotics and unmanned drones to explore the depths of the ocean to understand it and exploit their resources without causing irreversible damage to us who inhabit the planet’s surface.
The development of deep-ocean mining will be influenced by a number of factors - from technological to political and societal. Our lack of understanding the consequences of these activities and the environmental impacts they may entail would need to be addressed before such projects gain a "social licence" to operate.
Theodor Lisovoy, Managing Editor, Rough&Polished
Produced and published as part of the project "Best practices have a voice"
