| Written by Mark Buzinkay
Table of contents:
- What resources are we talking about in deep-sea mining?
- How does ore get collected from the sea-bed?
- What infrastructure is needed for deep-sea mining?
- The future of deep-sea mining
- FAQ
- Takeaway
- Glossary
What resources are we talking about in deep-sea mining?
The emerging field of deep-sea mining promises access to enormous and previously untapped mineral resources lying on and beneath the ocean floor, underpinning a new frontier in global resource extraction. Geologists and oceanographers now identify three primary mineral deposit types of commercial interest: polymetallic nodules scattered across abyssal plains, polymetallic sulphides concentrated around hydrothermal vents, and cobalt-rich ferromanganese crusts coating seamounts and ridges. In the vast Clarion‑Clipperton Zone (CCZ) of the Pacific Ocean alone, one estimate places up to 30 billion metric tons of nodules, with a notional value approaching US$18.4 trillion, according to a free-market consulting firm. (1) As the United States Geological Survey notes, the global tonnage of nodules and crusts may be on the order of hundreds of billions of tons of material, with contained metal concentrations that rival or exceed many land-based reserves. (2)
Polymetallic nodules sitting at depths of 4,000-6,000 metres typically contain manganese, nickel, copper, cobalt and rare earth elements. For example, in the CCZ, the nodules are estimated to hold as much as 0.27 billion metric tons of nickel, 0.23 billion metric tons of copper and 0.05 billion metric tons of cobalt, among other metals. Polymetallic sulphides, occurring around hydrothermal vent fields at depths of 1,400-3,700 metres, are rich in copper, lead, zinc and sometimes gold and silver, and are found along mid-ocean ridges and back-arc basins. (3) The cobalt-rich crusts, while more thinly distributed, present attractive concentrations of cobalt and other critical metals on submerged seamounts at shallower depths (often under 2,400 metres) and have drawn special interest given battery-metal demand.
Geographically, the nodules of the CCZ stretch across some 4.5 million km² between Hawaii and Mexico, and similar deposits occur in the Indian Ocean and parts of the Atlantic. The ferromanganese crusts are found in the Western Pacific, the Indian and Atlantic Oceans, coating undersea rises around Indonesia, Papua New Guinea, Japan, and seamounts in the mid-Atlantic. While commercial exploitation remains nascent, industry analysts describe deep-sea mining as potentially “a $20 trillion opportunity” thanks to the scale of material and the rising demand for electric-vehicle battery metals, turbine components and other critical minerals.
Yet the value figures come with caveats. The cost of extraction, the unknown technical challenges at extreme depths, environmental risk, and regulatory uncertainty all temper the promise. Moreover, some critics point out that the economic benefits to host states may be minimal compared to the scale of ecological risk. (4) Nonetheless, for an industry still at the cusp of first commercial deployment, the sheer magnitude of the resource base positions deep-sea mining as potentially transformative for global mineral supply and the green transition.
How does ore get collected from the sea-bed?
Here’s a draft for the second section of your article on the deep‑sea mining industry — explaining how the process works, the phases of a deep-sea mine, and how ore is extracted.
The process of deep-sea mining begins with a sequence of phases that mirror terrestrial mining—prospecting, exploration, and then production—but all under extreme pressure, remote conditions and with novel engineering challenges. The first phase is prospecting, during which companies leverage ships, towed sensors, autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) to map the sea-bed in the targeted zone. Geological, geophysical and geochemical surveys identify potential deposits of polymetallic nodules, sulphides or cobalt-rich crusts. The second phase is exploration, where the resource body is characterised in detail: its size, grade, morphology, depth, overburden and the environmental baseline is assessed. Sampling of the ore body, sediment thickness and surrounding ecosystem is undertaken, often requiring repeated submersible interventions and large volumes of data. In this phase, companies may test prototype mining machines and validate vertical lift systems. Only once exploration makes the case for economic viability does the project move into the third phase: exploitation or production. This is where actual extraction of minerals from the sea-bed occurs, with equipment launched from specially equipped production support vessels.
In the extraction phase, the mechanics differ depending on the deposit type. For polymetallic nodules — potato-sized concretions lying loose on the plains of the abyssal seafloor 4,000-6,000 m down — mining vehicles travel across the sea-bed sweeping up nodules with suction collectors or mechanical grab arms. These nodules are then pumped via a riser-lift system to the surface vessel, where the slurry of nodules and seawater is de-watered, stored and prepared for transport. (5) For polymetallic sulphide deposits, located near hydrothermal vents or mid-ocean ridges, extraction often relies on cutting or drilling into hard rock, then breaking the material mechanically or hydraulically and lifting it to the surface by pipe or in submersible vehicles. (6) For cobalt-rich crusts on seamount flanks, machine-mounted cutters or high-pressure water jets are used to remove crust layers, which are then pumped or hoisted to the ship. Once onboard the production support vessel, the ore is processed by separating water, reducing size, de-slurrying, and storing before dispatch to onshore processing plants.
Critical to this operation is the Riser and Lift System (RALS): a flexible or rigid pipe system that links the sea-bed mining vehicle with the surface ship. The vehicle collects the ore, feeds it into a pump, which sends the slurry upward through the riser under pressure. On deck, the slurry is de-watered, and mineral transport systems manage the solids. This vertical linkage is a key innovation in deep-sea mining. Supporting this are dynamic-positioning vessels stationed directly above the working area, launch/recovery systems for the crawler or collector vehicles, and umbilicals for power and communications to the sea-bed machines.
Each step of the process has to be measured against environmental and operational constraints. During extraction, huge volumes of sediment can be disturbed, creating plumes lateral or vertical in the water column, and the disturbance of the sea-bed may destroy or alter benthic habitats. (7) Because of this, one additional phase is often included in project design: closure and rehabilitation of the mining site. Though less defined for deep-sea mining than for terrestrial mining, it covers the shutdown of equipment, retrieval of the riser system, sediment remediation (if possible), monitoring and long-term ecosystem research.
To summarise: deep-sea mining follows prospecting → exploration → production → closure. Extraction technology varies by deposit type but typically uses a sea-bed mining machine (crawler, collector or cutter), a riser-lift system to transport ore to the surface, a production support vessel to handle processing and storage, and an umbilical network for monitoring and control. Given the novelty of the field and the extreme environment, deployment of these phases remains in experimental or pilot form in many cases, with commercial scale still ahead of us.
Illustration: Critical mineral resources in the deep sea (source: Miller et al 2018; Hein et al. 2013; image: World Resource Institute)
What infrastructure is needed for deep-sea mining?
Here is the third section for your article on the deep-sea mining industry, focusing on the infrastructure both below sea and above sea, and on the different types of vessels, their tasks and crews.
As the push for commercial-scale deep-sea mining accelerates, the infrastructure required spans from the ocean floor up to surface operations and shore-based support. Subsea equipment begins with mining vehicles travelling across the sea-bed or cutting into crusts, but just as critical is the infrastructure that links those machines to the surface vessel, and from there to onshore processing and logistics. On the sea-bed, major elements include the mining machine itself (crawler, collector or cutting tool), the riser and lift system (for nodules or slurries), power and communication umbilicals reaching down to the mining vehicle, and sensors for environmental monitoring. For example, the industry standard for polymetallic nodule recovery calls for a subsea collector machine operating at depths around 4,000 to 6,000 m, connected to a riser-lift system that sends the collected material up to the surface — the so-called Production Support Vessel. The subsea infrastructure must be engineered to withstand extreme pressures, function robustly for extended campaigns, and allow for real-time telemetry, control and monitoring of both resource extraction and environmental impact. Classification bodies such as the American Bureau of Shipping (ABS) have published guides specifically for mobile offshore mining units to ensure that subsea mining systems meet mechanical, structural and safety standards.
Above the sea surface, much of the heavy infrastructure resides on the ship or platform that serves as the command, processing and logistics hub. These Production Support Vessels (PSVs) or Mining Support Vessels (MSVs) are typically dynamically-positioned ships modified or converted from deep-water drillships. Their tasks include launching and recovering the sea-bed mining machines, assembling and deploying the riser and pump systems, handling the ore slurry delivered from the sea-bed, de-watering and storing the mineral product, and offloading to transport carriers. A case in point: a deep-sea mining PSV will carry a launch and recovery system (LARS) for the collector vehicle, a riser joint deck to build the riser-air-lift system (RALS), and onboard separation and storage facilities.
On the vessel side, the crew complements and their roles reflect the complexity of the operation. A typical crew will include vessel navigation and dynamic positioning officers, subsea systems engineers and technicians, ROV/AUV operators, mining machine operators, riser/pump system operators, sample processing and analytical staff, environmental monitoring specialists, and logistics and supply chain personnel. Ships such as the Hidden Gem (converted drillship) demonstrate this multi-role responsibility. It is reported to accommodate over 140 personnel when performing mining operations. (8) Another example, the vessel Nautilus New Era built for the former Nautilus Minerals project, was designed to host around 180 people and integrate ore-handling, riser systems and collection equipment.
In addition to the primary mining vessel, a full deep-sea mining campaign will also require support ships: supply vessels to bring fuels, provisions, spare parts, and consumables; anchor or mooring vessels if needed; research and monitoring vessels to deploy sensors, collect baseline data, and monitor sediment plumes and environmental effects; and transport carriers to offload the ore product from the PSV to onshore facilities. Onshore, the ore may be processed, refined and integrated into the mineral supply chain, requiring storage terminals, pulp/slurry treatment plants, conveyance systems, and infrastructure for final transport to smelters or battery-metal plants.
From an infrastructure standpoint, deep-sea mining thus requires the seamless integration of subsea systems (mining vehicles, riser-lift, umbilicals), a surface vessel (PSV/MSV) equipped for deployment, processing, storage and logistics, support fleet (supply and monitoring vessels), and onshore facilities. The interfaces between these layers are critical: the riser/pump system delivers ore to the surface, the PSV manages the collection and initial processing, and the transport chain transfers product to land. The engineering demands are high: extreme depth operations, remote robotic control, real-time data flows, large volumes of material pumped from the sea-bed, and environmental management requirements. With technology still maturing and regulatory frameworks evolving, the successful deployment of this infrastructure will be a key determinant of whether deep-sea mining becomes commercially viable.
The future of deep-sea mining
The future of deep-sea mining stands at a crossroads. On one hand, the accelerating global demand for battery metals, copper, nickel and cobalt—the raw materials underpinning the energy transition—offers a powerful economic impetus. A report by the International Energy Agency and other market analysts suggests that terrestrial sources may struggle to keep pace with projected demand, driving renewed interest in the sea-bed. (9) Meanwhile, the development of new mining technologies and the maturation of large-scale production support vessels promise that extraction from the abyss may be technologically feasible. The industry thus envisages a scenario in which deep-sea mining evolves from a speculative enterprise to one component of the global critical-minerals supply chain by the mid-2020s or early 2030s.
However, numerous formidable challenges loom. The first is regulatory and legal: existing frameworks—chiefly under the auspices of the International Sea-bed Authority (ISA)—are still incomplete. Without a fully adopted “mining code”, companies face uncertainty over licensing terms, environmental safeguards, and benefit-sharing arrangements. A second challenge is environmental. The deep-sea remains one of the least understood domains on Earth. Researchers warn that mining activities could trigger irreversible damage to unique benthic ecosystems, disrupt carbon sequestration functions and generate sediment plumes that extend far beyond the immediate footprint. Moreover, social and governance issues complicate the picture: questions of how host states, particularly small island nations, will share economic benefits from sea-bed mining remain unresolved, and community or indigenous-rights concerns may trigger opposition. On the technological and financial front, deep-sea mining firms must contend with enormous upfront investment, engineering risk, extreme operating environments and uncertain commodity prices. A vessel, mining machine, riser and lift system operating at depths of 4,000-6,000 metres is far more complex and expensive than a terrestrial mine. Some past enterprises have faltered under this burden. Because of this, commercial rollout may hinge on pilot projects to de-risk the supply chain and demonstrate reliable economics. At the same time, public acceptance and investor confidence require a transparent demonstration of environmental performance and safety. Without credible proof that deep-sea mining can be conducted responsibly and profitably, the industry may struggle to attract scale-up capital.
Looking ahead, a number of strategic pathways may shape the evolution of deep-sea mining. One scenario envisions a cautious phased rollout, beginning with nodules in relatively benign abyssal-plain settings, subject to strict environmental monitoring, before moving into more technically demanding sulfide or crust operations. Another scenario sees a moratorium or significant delay, as scientific, regulatory or reputational hurdles stall first-mover projects. For companies already committed, success will likely depend on forging strong partnerships with coastal states, investing in low-impact mining technologies, and demonstrating life-cycle sustainability. The industry may also need to pivot: rather than relying solely on sea-bed extraction, some firms may combine sea-bed minerals with more aggressive land-based recycling and circular-economy strategies to meet demand. In either case, the fate of deep-sea mining will hinge not only on geology, but on technology readiness, environmental governance, regulatory clarity and societal acceptance. The question now is not simply whether the resources lie beneath the waves, but whether humanity is prepared to unlock them in a way that aligns with a sustainable future.
FAQ: Understanding Deep-Sea Mining
What is deep-sea mining?
Deep-sea mining refers to the exploration and extraction of mineral resources from the ocean floor, typically at depths of 1,000 to 6,000 meters. The main targets are polymetallic nodules, sulfides, and cobalt-rich crusts containing key metals like nickel, cobalt, copper, and manganese—critical for batteries, renewable energy, and electronics.
Why is deep-sea mining controversial?
While it could ease shortages of critical minerals, scientists warn it may cause irreversible harm to fragile deep-ocean ecosystems. Sediment plumes, noise, and habitat destruction are among the major concerns, prompting calls for stricter regulation and moratoriums until more research is done.
Who is leading in deep-sea mining technology?
Companies such as The Metals Company, Allseas, and Global Sea Mineral Resources are among the frontrunners, conducting pilot projects in the Pacific’s Clarion-Clipperton Zone. Nations like Japan and China also hold exploration licenses under the International Sea-bed Authority, which governs mining in international waters.
Takeaway
Life offshore in deep-sea mining is a test of endurance and discipline. Crews spend weeks at sea aboard production support vessels, living in confined quarters while managing complex operations in one of Earth’s harshest environments. Safety is both a technical and human challenge—equipment operates under crushing pressures thousands of meters below. At the same time, onboard teams must coordinate around-the-clock shifts, heavy machinery, and helicopter or walk-to-work transfers. Maintaining physical and mental well-being, a strict safety culture, and seamless communication between deck and sea-bed define the human frontier of deep-sea mining as much as the pursuit of the minerals themselves.
Delve deeper into one of our core topics: Miner safety
Glossary
Polymetallic nodules are potato-sized mineral concretions found scattered across the deep-ocean floor, typically at depths of 4,000–6,000 meters. They form over millions of years as metals precipitate from seawater around a nucleus—often a shell fragment or rock. Rich in manganese, nickel, copper, and cobalt, these nodules are a major focus of deep-sea mining for battery and energy-transition materials. (10)
References:
(1) https://www.adlittle.com/sites/default/files/viewpoints/ADL_Seabed_mining_2024_0.pdf
(2) https://www.usgs.gov/centers/pcmsc/science/global-seabed-mineral-resources
(3) https://en.wikipedia.org/wiki/Deep_sea_mining
(4) https://planet-tracker.org/wp-content/uploads/2024/11/Race-to-the-Bottom.pdf
(5) https://deepseamining.ac/how_it_works
(6) https://360info.org/the-technology-behind-deep-sea-mining
(7) https://www.wri.org/insights/deep-sea-mining-explained
(8) https://www.marineinsight.com/types-of-ships/mining-ships-in-the-world/
(9) https://www.weforum.org/stories/2025/09/deep-sea-mining-critical-minerals/
(10) Hein, J. R., Koschinsky, A. (2014). Deep-ocean ferromanganese crusts and nodules. Treatise on Geochemistry, 13, 273–291. Elsevier.
Note: This article was partly created with the assistance of artificial intelligence to support drafting.
