In October, India’s National Institute of Ocean Technology (NIOT) successfully conducted an exploratory mining trial in the Andaman Sea, marking a significant step in the country’s efforts to tap into deep-sea resources. The trial aimed to extract polymetallic nodules from the seabed, a vital resource for the production of batteries used in electronics, electric vehicles and renewable energy technologies.
The trial followed surveys conducted by the Geological Survey of India (GSI), which identified polymetallic nodules within India’s Exclusive Economic Zone (EEZ). This area, which spans around 200 nautical miles from the coast, includes the Andaman and Nicobar Islands in the Bay of Bengal and the Lakshadweep island group in the Laccadive Sea. India holds exploration rights over this zone, and the successful trial is part of the country’s broader ambition to harness these deep-sea minerals for its energy transition and technological needs.
The technology behind the trial
To extract the polymetallic nodules from the ocean floor, NIOT deployed the Varaha-3 machine, a specially designed device capable of withstanding the harsh conditions of the Andaman Sea. Unlike the soft soils of the abyssal plains, the seabed in this region is rocky, which posed additional engineering challenges. Varaha-3, weighing six to seven tonnes underwater, features a comb-like collector mechanism designed to pick up nodules from the sea floor with minimal environmental disturbance.
The trial was conducted at a depth of around 1,200 meters, significantly shallower than India’s previous trial in the central Indian Ocean, where the Varaha-1 model was tested at a depth of over 5,000 meters. The nodules collected during the trial ranged in size from 60 to 120 millimeters.
Looking ahead, NIOT plans another trial in 2025, in collaboration with the GSI, to further refine the technology and improve the efficiency of the mining system. The focus will be on demonstrating the complete process of collecting, sizing, and transporting the nodules to the surface while minimizing environmental impact.
What are polymetallic nodules?
Polymetallic nodules are potato-sized rocks that form over millions of years on the ocean floor. These nodules contain valuable metals such as cobalt, copper, nickel and manganese—key materials for the production of lithium-ion batteries that power everything from smartphones to electric vehicles and renewable energy systems.
While the potential benefits of mining these resources are significant, they come with a growing set of environmental concerns. The extraction process disturbs the delicate deep-sea ecosystems, and the long-term impact of this disturbance remains uncertain. As the demand for these critical minerals increases, countries like India are keen to develop the technology to mine these resources sustainably.
India’s growing role in deep-sea mining
India has made substantial progress in its deep-sea mining efforts. The International Seabed Authority (ISA), the body responsible for regulating seabed mining, has granted India an exploratory license for a 75,000 square kilometer area in the Central Indian Ocean. The GSI has also been conducting surveys in the Andaman and Arabian Seas to identify additional sites for polymetallic nodule deposits.
India’s ‘Deep Ocean Mission’, launched with an estimated budget of Rs. 4,077 crores (approximately Rs. 40 billion), includes the development of deep-sea mining technologies as a key component. The mission reflects the country’s commitment to not only advancing its technological capabilities but also to ensuring the responsible exploitation of oceanic resources. NIOT is working on refining its mining systems, and the Institute of Minerals and Materials Technology is focused on developing the technology to extract and process these minerals.
While the technology is improving, NIOT scientists acknowledge that there are still significant challenges to overcome. “We are in the process of refining the system for collecting the nodules, transporting them to the surface, and ensuring minimal environmental impact. As we gather more data from trials, we are working on making the system more efficient and eco-friendly,” explains a senior scientist at NIOT.
Global opposition to deep-sea mining
Despite India’s progress, opposition to deep-sea mining is mounting around the world. Over 900 scientists and policy experts have called for a pause on deep-sea mining, citing concerns over the potential damage to marine ecosystems. As of 2024, 32 countries have either committed to or implemented a moratorium on deep-sea mining.
Environmental groups argue that the risks associated with mining in the deep ocean are too great, especially considering the limited understanding of deep-sea ecosystems. Studies published in prominent scientific journals such as Nature Geoscience and Current Biology have raised alarms about the potential consequences of mining for the delicate species and habitats in the deep ocean. Research from the Clarion Clipperton Zone (CCZ) of the Pacific Ocean, where polymetallic nodules are abundant, suggests that the impact of mining on biodiversity could be severe, potentially destroying habitats before we even understand their ecological roles.
Sofia Tsenikli of the Deep Sea Conservation Coalition (DSCC) emphasizes the importance of conservation, stating, “The message is crystal clear: humanity must find harmony with nature. We cannot afford to damage ecosystems that we still know so little about.”
Another study published earlier this year highlighted the risks of sediment plumes and waste discharge from mining operations, which can negatively impact the water column and benthic ecosystems. Rahul Sharma, editor of Deep-Sea Mining and the Water Column, warns that the discharge of waste water, if not managed properly, could harm marine life, especially if it’s released near the oxygen minimum zone, where many deep-sea species reside.
The ocean decade and future directions
As the world celebrates the United Nations Decade of Ocean Science (2021-2030), the debate over deep-sea mining is intensifying. The Ocean Decade aims to promote “transformative ocean science solutions for sustainable development,” balancing the need for resource exploitation with the imperative to conserve ocean ecosystems.
Sharma, who is also a consultant in deep-sea mining, believes that technological advancements can mitigate some of the environmental risks. “Scientists and technologists are becoming more conscious of the environmental impacts and are designing systems to minimize interaction with the seabed. While we are still in the early stages of developing deep-sea mining systems, the focus is on reducing the environmental footprint,” he says.
However, Sharma also argues that halting deep-sea mining entirely would be a “regressive step” and that further studies are needed to fully understand the long-term impacts of mining activities. He contends that, with the right systems in place, deep-sea mining can be managed responsibly.
The future of deep-sea mining will likely depend on the ability to balance the demand for these critical minerals with the need to protect marine ecosystems. As new studies and data emerge, the debate will continue, and the international community will have to decide how best to proceed in the face of competing environmental and technological priorities.
As the ISA prepares for its next steps and the leadership changes in 2025, the hope is that transparency, science, and sustainability will guide future decisions in the regulation of deep-sea mining.
