The untapped potential of deep-sea mining

While Australia is a major supplier of land-based battery metals, attention is turning to the deep sea, where untapped deposits of copper, nickel, cobalt, manganese, and rare earth elements lie on the ocean floor.

Is underwater mining the answer to meeting ballooning demand forecasts? As the world races towards net-zero emissions, the demand for critical minerals such as nickel, cobalt, graphite, and lithium increased by between eight and 30 per cent in 2023.

There are two primary sources of deep-sea minerals: seafloor massive sulfides (SMS) and polymetallic nodules.

SMS deposits form around hydrothermal vents, creating metal-rich chimneys that eventually collapse and solidify into mounds containing copper, zinc, silver, and gold.

While active SMS vents cannot be mined due to their marine ecosystems, extinct SMS structures could become future mine sites.

Polymetallic nodules, meanwhile, form over millions of years as metals in seawater precipitate onto biological particles like fish bones.

These nodules contain manganese, iron, cobalt, nickel, and rare earth elements, making them an attractive resource for electric vehicle batteries and renewable energy technologies.

While the Federal Government hasn’t taken a formal stance on deep-sea mining, with the NSW Government the only state to take a position on the matter by banning offshore mining in March last year, interest is growing with companies like DeepGreen Metals having explored Australia’s offshore resource potential.

DeepGreen estimates areas of the Pacific in which the company holds contracts may contain enough metal to power 280 million electric vehicles, approximately equal to the entire fleet of vehicles on U​S​​ roads today.

Internationally, companies like Moana Minerals (a subsidiary of Ocean Minerals) in the Cook Islands have received licences to explore for polymetallic nodules.

Moana Minerals chief executive officer Hans Smit described the company’s approach as a vacuum-based system that lifts nodules to the surface while minimising environmental impact.

“We create a suction force by using water injected into the into the nozzle which causes a vacuum and then we use that vacuum to lift the nodules off the seafloor as a slurry,” he said.

Deep-sea mining has yet to gain significant momentum, but if the pressure to meet mineral demand intensifies in the years to come, governments may prioritise the novel approach and a new industry could be born.