seabed mining

Seabed Mining

By: Staff Reporter
The limited opportunities to mine for minerals on land is making the world consider deep seabed mining as an alternative. But this can pose major destruction to marine biodiversity, given our limited knowledge of the effects of disturbing the high seas, especially in oxygen-minimum zones.
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In 2018, the first deep seabed mining will begin production in the territorial waters of Papua New Guinea. The project­­—Solwara I, is to be executed by Nautilus Minerals, which has been granted the lease to mine the deep sea for metals.

Nautilus holds approximately 450,000 sq km of exploration acreage in the western Pacific, covering Papua New Guinea, the Solomon Islands, Vanuatu, Fiji and Tonga, as well as international waters in the eastern Pacific (The Telegraph, 2014). Soil Machine Dynamics (SMD), which has been developing technologies for the subsea oil and gas sector since the 1980s, will be providing vehicles to be used for the mine.

The Solwara I is aimed at mining seafloor massive sulfides (SMS). Seabed SMS deposits contain high grade copper, gold, silver, zinc and other trace metals. The nodule mining machines—each of which weighs about 250 tonnes, will extract the ore through cutting, and then deliver it to a huge subsea pump that brings it to the surface. The operation of the machines is directed from a control centre on the vessel, where pilots and co-pilots monitor each vehicle using sonar and camera images (ibid).

Logic behind deep-seabed mining

Where mineral exploration on land has reached saturation point, and further mining can spell disaster for human communities, given its potential for destruction of sub-soil and agriculture, the open seas provide limitless opportunity for prospecting with the ultimate aim to mine. As nations like China and India industrialise, seabed mining can provide the much needed minerals to meet the increased demand from their industry.
Most significantly, the quality of copper and other metals is far superior to what can be obtained on land. While the current average copper grade on land is 0.62 per cent globally (and declining steadily), SMS deposits have copper grades of nearly 8 per cent. The gold is also a higher grade than most mines on land. Besides, the nodules have grades of more than one per cent nickel, 26 per cent manganese, and nearly 0.3 per cent cobalt. In fact, there is more copper on the sea floor than all the reserves on land.
Of course, the deep seas are not just the repository of SMS deposits. Industry and governments are interested in a lot more. Currently, there are three main types of deep seabed miningmineral deposits that are drawing attention and regulated by an international regime under the International Seabed Authority (ISA), a United Nations Organisation headquartered at Kingston, Jamaica.

Polymetallic or manganese nodules: These are potato-sized black nodules found on the abyssal plains at depths of 4000-6000 m. These are rich in manganese, nickel, cobalt, copper, lithium, molybdenum, iron and rare earth elements. The nodule deposits in the exclusive economic zone of the Cook islands in the South Pacific are drawing some serious attention, although 13 national consortia are also granted licenses for exploration the Clarion-Clipperton Fracture Zone (CCZ) between Baja and Hawaii in the Pacific. Nautilus jointly holds contracts with small Pacific islands like Nauru and Tonga for manganese nodule sites in CCZ.

Seafloor massive sulphide (SMS) deposits: These are found beneath deep sea hydrothermal vents along the 67,000 km volcanically active mid-ocean ridges and back arc basins between 1500-5000 m depth. These contain high-grade copper, gold, silver, zinc and other trace metals. Besides the SMS deposits in Papua New Guinea and adjoining areas within their EEZ that Nautilus Minerals holds lease to, there are other deposits in the Indian Ocean that China, India, Germany and Korea hold contracts for, while Russia and France hold leases for exploration on the Mid-Atlantic Ridge.

Cobalt-rich ferromanganese crusts: These are found on summits and flanks of seamounts at depths of 400-4000 m. Of the 10,000 seamounts rising at least 1000 m above the seabed, and another 90,000 smaller seamounts, many are in the EEZs of the central Pacific islands, and in the tropical Pacific. Cobalt crusts on seamounts are rich in cobalt, platinum, cerium, as also nickel, copper, iron, manganese, and several metals such as tungsten, bismuth and tellurium, besides rare earth elements. Currently, China, Japan and Russia are exploring international waters of the western tropical Pacific and have been contracted areas by ISA.

Besides these, marine phosphorites and methane hydrate resources like gas-hydrates are also found in shallower waters of 100-500 m depth. Marine phosphate mining is under consideration off Namibia, off Baja Mexico and New Zealand. Meanwhile, Japan has tested methane hydrate extraction from its offshore waters (Steiner, 2015).

India too, has staked its claim to mine the Indian Ocean for nodules and SMS (Sharma, 2015). It is among the 26 countries, others being China, Korea, Russia, Germany and France, that have claimed areas for exploration for hydrothermal sulphides and polymetallic nodules in the Indian and Atlantic oceans.

Deep seabed mining is justified on the ground that it would bring prosperity to small island states in the Pacific, which are too remote to have a tourism industry, and only survive on fishing. Besides, according to Nautilus Minerals, the carbon footprint of deep seabed mining is smaller than that on land. However, this is fiercely contested by activists and researchers who advise restraint.

Legal protection for marine biodiversity

A regulated authority for deep seabed mining has been years in the making. In a radical departure from the tradition of open access and freedom of the high seas, the 1982 United Nations Convention on the Law of the Sea (UNCLOS) declared the seabed area beyond national jurisdictions and its mineral resources as the ‘common heritage of mankind’, to be administered for the benefit of mankind as a whole. All mineral exploration and exploitation activities had to be sponsored by a state party to UNCLOS and approved by the ISA. In its 20 years of existence, ISA has adopted regulations and guidance for exploration activities for all the three mineral resources so far known on deep seabed mining. In 2013, it commenced the development of regulations to govern the future exploitation of seabed minerals, starting with polymetallic nodules.

UN Convention on the Law of the Sea

UNCLOS in Part XI, together with its 1994 Implementation Agreement relating to Part XI, sets forth the international legal framework for activities related to deep seabed mining and marine scientific research.

The guiding principle of the common heritage of mankind is manifested in many ways:

  • all rights in the resources of the area are vested in mankind as a whole;
  • no state or natural or juridical persons can claim, acquire or exercise rights in connection to resources in the area except in accordance with Part XI;
  • all mining and any minerals recovered may only be alienated in accordance with UNCLOS and the rules adopted by the Authority;
  • states are required to ensure that they exercise ‘effective control’ over any activities by their state enterprises and other natural or juridical persons they sponsor;
  • activities in the area, including marine scientific research, are to be carried out for the benefit of mankind as a whole; and
  • financial and other economic benefits from seabed mining are subject to equitable sharing under rules to be developed by the Authority (UNCLOS Articles 133-143).

UNCLOS requires that necessary measures be taken to ensure effective protection for the marine environment from harmful effects which may arise from mining-related activities. UNCLOS (in Part XII) requires national rules for pollution from seabed mining activities in the area as well as within national jurisdiction to be no less effective than international rules, standards and recommended practices and procedures (UNCLOS articles 208-209). Additionally, all states share a common obligation to protect and preserve the marine environment, including rare or fragile ecosystems as well as the habitat of depleted, threatened or endangered species and other forms of marine life (UNCLOS Articles 192 & 194.5).

Dangers of seabed mining

However, notwithstanding all the provisions made under UNCLOS to protect the marine environment, deep seabed mining encompasses dangers and problems that are unforeseen as yet.
For an average 10,000 metric tonnes of nodules mined per day, about 40,000 metric tonnes of sediment would get disturbed. Every year, 300-600 sq km will be disturbed for mining 1.5-3 million metric tonnes of nodules per year. Besides, for every metric tonne of manganese nodules mined, 2.5-5 tonnes of sediment will get resuspended. Adjacent areas will have higher sedimentation rates, and suspended loads will travel over long periods laterally in the water, causing clogging of filter feeding apparatus of benthic organisms. Sudden increase in suspended loads will increase turbidity in waters and affect pelagic organisms. Moreover, debris and sediment lifted and transported with the minerals will get discharged at the surface and create turbidity. This will decrease available sunlight for photosynthesis, causing long term effects on biological productivity of the marine ecosystem. Bottom water with high nutrient values brought up due to mining can also cause artificial upwelling (Sharma, 2015).
Since heavy nodule collecting machines will be deployed for mining, sediment and associated fauna will be crushed all along the track of the nodule collector. This will also see smothering and entombment of benthic fauna, and increase the mortality of many plankton and nekton species in the oxygen-minimum zone.
Additionally, pollution may also occur at shallow depths through surface spills or leakage from the riser or discharge pipes (Accountability Zero, 2015). This is particularly pertinent for marine biodiversity since no comprehensive studies have yet been conducted on the toxicity of heavy metals to marine organisms.
Studies done so far on the effects of disturbance and recovery post-disturbance in marine waters, such as DISCOL (Germany) have shown that although benthic organisms displayed a quantitative recovery post-disturbance, the faunal composition was not the same as before. A similar study conducted by India through the National Institute of Oceanography (NIO)-INDEX, Goa, has also shown that the lateral mixing of sediment in marine waters resulted in a change in physic-chemical conditions, and reduced biomass around the disturbed area (ibid).
There are other problems too. Activists have been pointing out that the light and sound effects caused due to mining can have a deleterious effect on marine fauna and sea-birds. The hydrothermal vents especially are a phenomenon that are hardly understood. Mining could have hitherto unknown effects on these vent systems and cause irreparable destruction.

India’s stand on seabed mining

India is one of four nations that has staked its claim for hydrothermal sulphides and is the only country attempting to mine for polymetallic nodules in the Indian Ocean. Dr Maruthadu Sudhakar, Director, Centre for Marine and Living Resources Ecology (CMLRE) and member, International Seabed Authority, who represents India on the international body dismissed the fear of turbidity in the waters and a lateral movement of bottom segment affecting fisheries catch and hence affecting the food security of coastal populations. The Indian contracted area is 2000 km from the southernmost tip of the Indian mainland. “It is south of the equator and far off from any inhabited landmass— hence there can be no danger of a fall in fish landing. Operations will be localised and will be on the high seas in the Indian Ocean which is a completely dynamic system with sea state above 5 on the Beaufort scale”, he added. “Besides, the technology India plans to use is extremely advanced. Unlike the Lockheed Martin, demonstration equipment used in the 70s where a rigid type system was used, India will have a flexible hose system wherein the mined manganese will travel in slurry form to the ship. Of course there is no denying the disturbance of the ocean bed but we are committed to maintain the sanctity of the ocean system for 400 km all around”, Sudhakar opined.
As regards, the decreasing sunlight for photosynthesis both Sudhakar and the senior scientist from National Institute for Ocean Technology (NIOT), Dr Ananda Ramadass Gidugu pointed out that “photosynthesis occurs only 100-150 m from the ocean surface and since, India plans to mine polymetallic manganese nodules at 4-5.5 km from the ocean surface, there is no question of biological productivity of the marine ecosystem getting affected in the intermediate and upper layers of waters where the biota occurrence and diversity is more pronounced”.

Latest international legal developments

In view of the challenges imposed, especially to marine diversity, as per a resolution passed on June 19, 2015, the UN General Assembly decided to develop an international legally binding instrument under the UNCLOS on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction. To that end, prior to holding an intergovernmental conference, a Preparatory Committee, open to all member-states of the United Nations, members of the specialised agencies and parties to the Convention, was to be set up to make substantive recommendations for a draft text of an international legally binding instrument under UNCLOS.
The Preparatory Committee started working and held two meetings in 2016, and will submit its report by 2017-end. Negotiations will be aimed at addressing topics identified in the package agreed in 2011, namely the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction, marine genetic resources, including questions on the sharing of benefits, measures such as area-based management tools, including marine protected areas, environmental impact assessments and capacity-building and the transfer of marine technology.
The negotiations intend to build on the general framework provided by UNCLOS and the general principles set out in the United Nations Fish Stocks Agreement (Art. 5) and the Convention on Biological Diversity (CBD), Nagoya Protocol and other international instruments as a guide.

Rationale for restraint

It is unclear what disturbing the ocean bed will hold for us in future. In fact, there is a lot more wisdom in keeping away from venturing into the unknown, and limiting our greed for nature’s resources. Although it is very clear that no government or private contractor can ever start exploitation of the ocean’s resources unless the international seabed authority grants it a mining code. When mining is done in territorial waters of a country, the law of that country will prevail. This is the case where Nautilus Minerals’ mining in the territorial water of Papua New Guinea is concerned. In such a case, one cannot be sure of what effect it can have on the marine fauna, the ecosystem or fisheries. As against industry and governments extending the argument of depletion of land-based mineral resources, activists advocate doing away with the ‘economy of waste’, and increased efficiency of metal use in the global economy (Steiner, 2015).


Governments and industry are all set to mine the seas for mineral resources, with the availability of metals and minerals on land peaking. However, deep seabed mining is uncharted territory, of which we have extremely limited knowledge. It can have huge ramifications for marine biodiversity, and badly affect food security for coastal populations in future.


The Telegraph. 2014. Deep Sea Mining is the future in Papua New Guinea.

R. Steiner. 2015. Deep Sea Mining a New Ocean Threat.

R. Sharma. 2015. Environmental Issues of Deep Sea Mining. Procedia Earth & Planetary Science 11 (2015) & Elsevier B.V. 2015

Nautilus Minerals. 2014.

Accountability Zero. 2015.

IUCN. 2016. Climate change dramatically disrupting nature from genes to ecosystems.

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