How deep-sea mining can help to address the minerals crunch

Experts are exploring the possibility of mining seabeds despite environmental concerns in a push to meet rising demand for essential minerals amid green energy transition

A subsea mining machine being built for Nautilus Minerals in England. Deep-sea mining is increasingly emerging as a viable option to meet demand for rare earth metals required to meet net-zero goals. Show more

Running from Hawaii to Baja California, five kilometres beneath the Pacific Ocean, lies one of the richest mineral treasures on the planet. An area larger than India, it is pitch black and temperatures dip below 4°C and 500 atmospheres of pressure. But the Clarion-Clipperton Zone, or the CCZ, is also home to thousands of species of coral, starfish, anemones and others unknown to science – making the decision on whether to mine the deep sea a challenging one amid the green energy revolution.

The supply of raw materials essential for the energy transition is increasingly critical. To operate, the likes of wind turbines, solar panels, electric vehicle motors, hydrogen electrolysers, batteries and electrification need copper, lithium, rare earth elements, precious metals and others. Consumption by clean energy systems by 2040 will grow by six to 21 times for cobalt, six to 19 times for nickel, and three to eight times for manganese, according to the International Energy Agency.

Obtaining these has become a tricky topic. Some, particularly copper, are already required in large quantities and concerns have arisen that supply could fail to keep up later this decade as the world’s leading mines are exhausted and lack of investment takes its toll.

Other minerals have been little-used historically. Cobalt is mostly produced as a by-product of copper and nickel mining, making it hard to increase production independently. Output of some metals is concentrated in China, Russia and the US, countries that might use control of resources for strategic ends.

By contrast, two thirds of the global cobalt supply comes from the Democratic Republic of Congo, which is associated with poor labour conditions, corruption and political instability. As prices for these metals rise, governments demand higher taxes, as in Chile, the world’s leading copper miner.

Mining on land creates environmental problems: disturbance to communities; damage to ecosystems from land use, tailings heaps and contaminated water run-off; acid rain from sulphur in the minerals; and high greenhouse gas emissions from supplying power to the mines and ore smelters.

Combine these problems and it is not surprising that attention has returned to mining the deep sea. The CCZ alone is estimated to contain more cobalt, manganese and nickel than all known terrestrial deposits. These oceanic minerals are not owned by any state but licences to explore them are administered by the International Seabed Authority, or ISA, an agency of the UN.

The ocean floor contains three main types of mineral deposits: the polymetallic nodules scattered across the floor of areas such as the CCZ; metallic crusts on underwater mountains that contain manganese, cobalt and platinum among others; and sulphides accumulated at “black smokers”, or vents of superheated volcanic waters where zinc, copper, silver and gold can be found.

So far, these resources are not being mined but a number of ambitious companies have the funding and technology to try. Tractors and suction devices could hoover up the sediment and bring it to a ship that would separate the ore and dump the rest back into mid-level waters.

In May, a trial of a robotic harvester in the CCZ by a subsidiary of Belgium’s Deme group successfully collected nodules. The ISA has awarded the company an exploration area twice the size of Belgium. The next trial comes in 2024, with hopes for commercial production by 2028.

But should we exploit this pristine area? Along with the Antarctic, it is virtually the last untouched environment on Earth.

Sediments accumulate in the deep waters at a rate as slow as a millimetre a millennium. Thirty years after a simple test of disturbing the seabed off Peru in 1989, there has been no recovery. Meanwhile, creatures such as the ghost octopus, which was discovered only in 2016 off Hawaii, attaches themselves to a hard ocean-bottom object for several years to hatch their eggs – a hard object that could be a metal nodule.

Many more such undiscovered creatures and unknown ecosystems, no doubt, lie hidden below the ocean in the CCZ area. Seabed mining could destroy these habitats before we even understand them.

So, what are the alternatives? Greenpeace advocates recycling and the “circular economy”, with the aspiration of zero waste. Batteries and their metals can be recycled and a major effort is justified to design green energy systems better to allow their re-use.

But even a circle needs a starting point. The renewable and electric economy needs to be built and the first generation of equipment come to obsolescence before substantial recycling can begin.

Alternative materials can be used. Lower-cobalt batteries have already become more popular, although they require more manganese. Electric car maker Tesla is now touting lithium-iron-phosphate batteries as the likely option for two thirds of its needs, made from cheaper and more readily available ingredients.

Copper can be replaced to an extent with aluminium or plastics, although plastics come from fossil fuels. These substitutes are often heavier, less energy-efficient and not always suited for the most demanding applications in renewable energy and electric vehicles.

Given a deadline of only 29 years to many countries’ net-zero carbon goals, and with the crunch in copper, in particular, expected by mid-decade, there is limited time for lengthy research. Despite real concerns, the deep-sea mining industry is emerging with far more environmental care and awareness than its onshore cousin, or the early days of the petroleum business. It is the only extractive business governed by an international system.

It may turn out that deep-sea mining is not profitable, that the environmental effects are unacceptable or that mineral needs may be better met through onshore mining, recycling and alternatives. However, the need for a rapid green energy revolution to slow climate change means tough choices.

If carefully studied, tightly regulated and watched by independent observers, the industry of ocean floor minerals can stake a claim.

Robin Mills is chief executive of Qamar Energy and author of The Myth of the Oil Crisis