Seabed watchdog accuses deep-sea miner of ignoring risk procedures after spill in Pacific

Article by Kerry Hebden

TMC the metals company Inc.
The Allseas-designed pilot nodule collector vehicle on NORI's surface production vessel, Hidden Gem. The vehicle was recently used by NORI during deep-sea nodule collection trials

NAURA OCEAN RESOURCES (NORI), the company which sparked debate into deep sea mining in 2021, has been investigated by the International Seabed Authority (ISA) after causing a slurry spill in the Pacific last year. According to ISA, the incident, which was reported as “not causing serious harm to the marine environment” was a result of the company failing to follow its own risk management rules, and having project crew that were not prepared or trained to manage the risk. 

NORI, a subsidiary of Canadian company The Metals Company, formerly DeepGreen Metals, is also sponsored by the government of the Republic of Nauru, a tiny island country in Micronesia, northeast of Australia. 

NORI already holds a 15-year contract for exploration for polymetallic nodules in the eastern Clarion Clipperton Zone (CCZ), a 4.5m km2 abyssal plain stretching between Hawaii and Mexico known for ocean floor potato-sized rocks containing cobalt, nickel, manganese, and copper. 

The firm became the centre of attention in 2021 when it notified ISA, a UN-mandated body set up to govern seabed activities, that it planned to commence deep-sea mining within two years – an option available to all member states of the authority. 

As part of its planned mining activities, NORI carried out a test of its polymetallic nodule collector system components in its contract area between 10 September and 15 November 2022. In the inspection report produced following the test, ISA noted that around 3,200 t of nodules were collected with an average size of approximately 3 cm across.  

The nodule collector vehicle resembles a large metallic vacuum cleaner, albeit somewhat more complicated-looking, which trundles across the ocean floor on tank-like tracks and hoovers up nodules. NORI said that over 90% of the entrained sediment is expected to be separated from the nodules inside the collector and discharged behind it, with most sediment settling back on the seafloor within a few hundred metres. The collected nodules are then transported up a 4.3 km-long riser system to a surface vessel where they are stored and dried out. 

On 12 October 2022, however, during an eight-hour test window to increase production, NORI estimates that between 48–72 m3 of seawater with a sediment concentration of approximately 5 kg per 100 l went overboard. This was caused by a surge in the volume of water flow which exceeded the buffer capacity of the cyclone separator at the top of the airlift riser.  

NORI said it observed the discharge visually at the time of the event and noted that the surface water’s appearance returned to normal conditions after 60 minutes, but it did not take photos of the water “plume” dispersing in real time. It verbally reported the incident to the Compliance Assurance and Regulatory Management Unit (CARMU) on 28 October 2022, and submitted a written report 16 days later. 

The report by ISA also states that based on the initial information provided by NORI, a preliminary assessment by the Office of Environmental Monitoring and Mineral Resources (OEMMR) indicated that as the overflow was dominated by bottom seawater and minor sediment material, it did not pose a risk of harm to the marine environment – a conclusion that was shared by NORI. 

ISA attributed the cause of the overflow to decision-making, incident management, and execution “not rooted in a robust risk-based assessment”. It also said contractor personnel on board the vessel “did not fully apply internally established risk management tools and procedures during the event”.  


Apart from the late reporting of the overflow, the report says the investigation did not identify any non-compliances, and it concluded by making recommendations including conducting an engineering review of the airlift system, its technical operation and supervision, to identify areas for improvement. 
Duncan Currie, a lawyer at the non-profit Deep Sea Conservation Coalition, told the Financial Times that ISA’s judgment of the event was not harsh enough. “If [ISA] does not consider a spill such as this to be a problem, this raises real concerns about their ability to regulate a full-blow mining operation,” he said. 

ISA responded by saying its staff were bound by UN policies and rules, and upheld the “highest standards of efficiency, competence and integrity”, the FT said. 

To mine, or not to mine

The question of whether to mine the deep sea has been raging for years. Some researchers and environmental groups warn that the removal of metal-laden nodules would have long-lasting, detrimental effects for deep-sea fauna and the species that rely on them – thousands more of which have just been discovered. In a bid to halt further progress in the industry, in 2021, 778 marine science and policy experts from over 44 countries signed a petition calling for a moratorium on deep-sea mining “until sufficient and robust scientific information has been obtained”. 

Conversely, countries including China and Japan, and firms including The Metal Company, argue that deep-sea mining is crucial for powering the green transition from fossil fuels, and is a less environmentally and socially damaging alternative to mining on land. 

NORI’s issue of intent to mine the CCZ has reignited the debate again, as the process triggered the so-called “two-year rule”, a mechanism intended to push ISA into finalising rules, regulations and procedures governing the industry no later than 24 months after NORI’s application. 

ISA regulates deep-sea mining in this region because the CCZ is outside national jurisdiction. 

Currently, contracts for mining exploration in the CCZ have been granted to 16 deep-sea mining contractors, over areas covering approximately 1m km2. So far though, no exploitation contracts have been issued, as there are no set regulations in place. 

Some progress has been made on ISA’s draft regulations, but legal experts say a “completed” version is a long way off yet, and a recent international meeting to negotiate deep-sea mining rules has ended with no agreed consensus on the matter. 

Instead, delegates settled on an 11th-hour agreement to hold formal discussions next year on the future of deep-sea mining and the protection of the marine environment. 

Article by Kerry Hebden

Staff reporter, The Chemical Engineer

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