Ocean minerals: polymetallic nodules, the Deep Ocean Mission and offshore blocks

Detail

Why the ocean floor matters for minerals

• The ocean floor has its own relief: continental shelf, continental slope, abyssal plains, mid-ocean ridges and seamounts. Different minerals form in different parts of this relief.
• Abyssal plain: the flat, deep floor of the open ocean, about 4,000–6,000 m deep.
• Mid-ocean ridge: an underwater mountain chain where two plates move apart and new crust forms.

• Seamount: an underwater volcanic mountain that does not reach the sea surface.

• Ocean minerals are a growing source of critical minerals (minerals a country needs for clean energy, electronics and defence, but whose supply is at risk). Examples are cobalt, nickel and copper.

• India has 7,517 km of coastline, nine coastal states and 1,382 islands. This gives it a large sea area to explore (PIB, 2025) [2].
• India's Vision of New India by 2030 lists the Blue Economy among ten core growth dimensions. Blue Economy means all economic activity based on the sea, such as fishing, shipping, seabed minerals, marine biotechnology and tourism [2].
• The UN has named 2021–2030 the "Decade of Ocean Science for Sustainable Development" [2].

Three types of deep-sea mineral deposits

Deposit	Where it forms (relief)	How it forms	Main metals	India's interest
Polymetallic (manganese) nodules	Abyssal plains	Metals in seawater and sediment slowly settle in layers around a small core (a shark tooth or a rock bit)	Manganese, nickel, copper, cobalt, iron	ISA contract, Central Indian Ocean Basin (2002)
Polymetallic sulphides	Mid-ocean ridges, near hydrothermal vents	Seawater seeps into hot crust → picks up metals → hot fluid rises out of a vent → it meets cold water and the metals settle as sulphides	Copper, zinc, lead, gold, silver	ISA contract, Central and South-West Indian Ridges (2016)
Cobalt-rich ferromanganese crusts	Slopes and tops of seamounts	Metals from seawater build up as a hard coating on bare rock	Cobalt, manganese, nickel, rare metals	2024 application, Afanasy-Nikitin seamount

• A hydrothermal vent is an opening on the seabed that releases very hot, mineral-rich water.

Polymetallic nodules

• Polymetallic nodules are potato-sized lumps lying on the deep ocean floor. They are rich in manganese, nickel, copper and cobalt. "Polymetallic" means "containing many metals". NCERT Class 10 calls them manganese nodules on ocean beds.
• How they form:
• Dissolved metals in seawater and in the mud on the seabed settle around a tiny core.
• They build up in thin layers, one around another, like the layers of an onion.

• They grow only a few millimetres in a million years, so nodule fields are very old and cannot be replaced.

• Where they are found:

• In the world: the abyssal plains of the Pacific, Indian and Atlantic Oceans.

• For India: the Central Indian Ocean Basin (CIOB), a deep basin in the Indian Ocean far south of the Indian peninsula.

• In December 2022, India's autonomous underwater vehicle Ocean Mineral Explorer (OMe 6000) surveyed India's CIOB nodule site at a depth of 5,271 m. It worked from the research vessel Sagar Nidhi, surveyed 14 sq km and mapped a 1 km × 0.5 km patch in detail. The aim was to study how the nodules are spread out and what life lives there [2].

• Nodules are not found only in very deep water. Over 100 kg of cobalt-rich polymetallic nodules were collected from 1,173 m depth in the Andaman Sea [2].

India's seabed rights under the Law of the Sea

• UNCLOS (United Nations Convention on the Law of the Sea, 1982) is the global treaty that sets the rules for using the seas. It calls the seabed beyond national limits the "Area" and treats its minerals as the common heritage of mankind, which means no single country owns them.
• The International Seabed Authority (ISA) is the UN body set up under UNCLOS. It controls mineral exploration and mining in the Area, and its headquarters is in Kingston, Jamaica.
• Pioneer investor status (1987): India was the first country to get this status. A pioneer investor is a country that spent money on seabed exploration early, so it was given a reserved area before the full ISA system began.
• India's ISA contracts and applications:

Year	Resource	Location	Status
2002	Polymetallic nodules	75,000 sq km in the Central Indian Ocean Basin	Exploration contract
2016	Polymetallic sulphides	Central Indian Ridge and South-West Indian Ridge	Exploration contract
2024	Cobalt-rich ferromanganese crusts	Afanasy-Nikitin seamount, Central Indian Ocean	Application filed (verify current)

• Exploration vs exploitation:
• An exploration contract allows only survey, sampling and testing.

• Commercial mining needs the ISA mining code (the rules for mining, royalties and environmental protection). This code is still not settled.

• Under the Deep Ocean Mission, India's own nodule-mining plans are meant to support commercial work "once global rules are set by the International Seabed Authority" [2].

• The moratorium debate: many countries want a moratorium (a temporary stop) or a "precautionary pause" on deep-sea mining. Their reasons:
• Mining machines scrape the seabed and destroy habitats that took millions of years to form.
• Sediment plumes (clouds of stirred-up mud) spread over large areas and smother life.
• Deep-sea species grow slowly, and many are still unknown to science.

Deep Ocean Mission (DOM)

• What it is: a Ministry of Earth Sciences (MoES) mission to develop technology to explore the deep ocean and use its living and non-living resources in a sustainable way.
• The Union Cabinet approved it in June 2021. MoES formally launched it on 7 September 2021 [2].

• Cost: ₹4,077 crore over five years, carried out in phases [2].

• Six components (2021):

#	Component	What it does
1	Deep-sea mining technology and crewed submersible	Builds a submersible for 3 people to reach 6,000 m, plus an Integrated Mining System to lift nodules from the Central Indian Ocean [2]
2	Ocean climate change advisory services	Observations and models to forecast climate variables over seasons to decades [2]
3	Deep-sea biodiversity	Bio-prospecting (searching for useful plants, animals and microbes) and their sustainable use [2]
4	Deep ocean survey and exploration	Finds multi-metal hydrothermal sulphide sites on Indian Ocean mid-ocean ridges [2]
5	Energy and freshwater from the ocean	Design of an offshore OTEC-powered desalination plant [2]
6	Advanced Marine Station for Ocean Biology	Builds skills in ocean biology and engineering and turns research into products [2]

• OTEC (Ocean Thermal Energy Conversion) makes power from the temperature difference between warm surface water and cold deep water. Desalination removes salt from seawater to make fresh water.

Samudrayaan and Matsya-6000

• Samudrayaan is India's first crewed deep-ocean project under the DOM. Its vehicle is Matsya-6000.
• Matsya-6000 is a Human Occupied Vehicle (HOV), a submersible that carries people inside it.
• It is self-propelled and built to carry 3 people to 6,000 m [2].
• It is built to work for 12 hours at a time and can keep the crew alive for up to 96 hours in an emergency [2].

• It has a high-density Li-Po battery, an underwater acoustic telephone, a drop-weight emergency escape system and bio-vests that track crew health [2].

• Who builds it: NIOT (National Institute of Ocean Technology, Chennai, under MoES) together with VSSC, ISRO [2].

• Its titanium crew sphere is joined using Electron Beam Welding, a process developed by ISRO's Liquid Propulsion Systems Centre (LPSC) after 700 trials [2].

• Trials so far:

• Dry tests across a 500 m operating range [2].
• Wet trials, with and without crew, at L&T Shipyard, Kattupalli Port, Chennai in January–February 2025 [2].

• 5–6 August 2025: NIOT aquanauts Raju Ramesh and Cdr. Jatinder Pal Singh (Retd) dived to 5,000 m in the Atlantic Ocean on the French submersible Nautile, with IFREMER (French marine research institute). It was India's first dive to this depth [2].

• Planned timeline (as of August 2025): a shallow-water demonstration up to 500 m by early 2026, deep-water tests by mid-2027, and science missions with Matsya-6000 in 2027–28 [2] (verify current).

• With a 6,000 m reach, Matsya-6000 can visit most of the depths where nodules, sulphides and crusts lie.

Offshore mineral blocks auction

• Legal base: the Offshore Areas Mineral (Development and Regulation) Act, 2002, as amended in 2023, made auction the only way to give out mineral rights in India's offshore areas.
• It covers India's territorial waters, continental shelf and EEZ.

• It is separate from the MMDR Act, 1957, which governs minerals on land.

• Sea zones (UNCLOS):

Zone	Extent from the coast (baseline)	India's rights
Territorial waters	Up to 12 nautical miles	Full sovereignty, like land
Continental shelf	Seabed of the natural underwater extension of the land, at least 200 nautical miles	Rights over seabed minerals
EEZ (Exclusive Economic Zone)	Up to 200 nautical miles	Sole rights to fish, minerals and energy
The Area (beyond national limits)	Beyond the continental shelf	Common heritage; ISA controls it

• Resource-classification link (NCERT Class 10):
• Minerals inside the EEZ are national resources.
• Minerals beyond 200 nautical miles are international resources, managed by international bodies such as the ISA. No country can use them without international approval.

• India's CIOB nodules are in the Area, so India needs an ISA contract. The Andaman blocks are inside India's own zone, so India can auction them.

• First tranche, November 2024: 13 blocks (tender notice by the Ministry of Mines, 28 November 2024):

Mineral	Location	Use
Construction sand	Off Kerala (Kollam), Arabian Sea	Building and infrastructure
Lime mud	Off Gujarat, Arabian Sea	Cement and lime
Polymetallic nodules and crusts	Off the Andaman and Nicobar Islands, Andaman Sea	Cobalt, nickel, manganese and other critical metals

• Opposition in Kerala: fishers' groups in Kerala protested against the sand-mining blocks off Kollam (verify current). Their concerns:
• The Kollam sea area is a rich fishing ground, and seabed dredging harms the places where fish breed and feed.
• Turbid water and noise drive fish away, which cuts fishers' catch and income.
• Removing sand may increase coastal erosion.

Conservation angle

• Seabed minerals are non-renewable and form extremely slowly. Like land minerals, they must be used with planning, recycling and care for the environment.
• India's approach combines exploration (ISA contracts), technology (DOM, Samudrayaan) and regulated auctions (2023 amendment). The international mining code and local livelihood concerns are still unresolved.

Prelims Hooks

• India was the first country to get pioneer investor status (1987) for seabed nodules under the UNCLOS regime.
• India's ISA nodule contract (2002) covers 75,000 sq km in the Central Indian Ocean Basin, not in the Pacific's Clarion-Clipperton Zone.
• Match the deposit to its setting: nodules → abyssal plains; sulphides → mid-ocean ridges (Central and South-West Indian Ridges, 2016); cobalt crusts → seamounts (Afanasy-Nikitin, 2024 application).
• Deep Ocean Mission: MoES, approved June 2021, ₹4,077 crore over 5 years [2].
• Matsya-6000: 3 crew, 6,000 m, built by NIOT with VSSC-ISRO, under Samudrayaan [2].
• August 2025: Indian aquanauts reached 5,000 m in the Atlantic aboard the French submersible Nautile (IFREMER) [2].
• OMe 6000 surveyed the CIOB nodule site at 5,271 m in December 2022 [2].
• First offshore tranche (November 2024, 13 blocks): sand → Kollam (Kerala); lime mud → Gujarat; nodules and crusts → Andaman and Nicobar.
• Trap: offshore minerals are auctioned under the Offshore Areas Mineral (Development and Regulation) Act, 2002 (amended 2023), not under the MMDR Act, 1957.
• Trap: the ISA grants exploration contracts only in the "Area" beyond national limits. It does not license blocks inside India's EEZ.

Mains Points

• Why India is going into the deep sea (GS-III): India depends on imports for cobalt, nickel and copper, which it needs for batteries and the energy transition. CIOB nodules, ridge sulphides and seamount crusts are a long-term domestic and strategic source. The DOM (₹4,077 crore) and Matsya-6000 build the technology needed to use them [2].
• Environmental and livelihood costs: seabed mining destroys slow-forming habitats, creates sediment plumes and threatens unknown species. Near the coast, as at Kollam, dredging threatens fishing grounds and fishers' incomes, and may add to coastal erosion. Answers should call for baseline environmental studies, environmental impact assessment and consultation with fishers before mining.
• Governance gap: the ISA mining code is still unsettled and many countries want a moratorium. India's own commercial mining in the Area must wait for global rules. Inside the EEZ, the 2023 amendment allows auctions but needs strong environmental safeguards.
• Resource-planning link: the national vs international resource split (EEZ vs the Area) explains why India uses auctions at home and ISA contracts abroad. Both are part of sustainable resource planning and the conservation of non-renewable minerals.