Deep sea gold rush — A race to the bottom

While deep-sea mining activities are gaining interest around the world, a better understanding of its environmental impact is necessary. Some exploration companies have veered away from terrestrial mining and are embarking on a blind race to the bottom of the oceans, and there may be potentially devastating consequences to the marine environment.

The seabed is rich in biodiversity, and is the largest habitat for life on Earth. 1 Under immense pressures and freezing temperatures, organisms in the deep-sea tend to congregate around three types of geographic features abyssal plains, seamounts, and hydrothermal vents. 2 But these exact features are the ones targeted for deep-sea mining as they contain polymetallic nodules, cobalt crusts, and polymetallic sulfides rich in mineral deposits. 3 Metals on the seabed include copper, nickel, silver, gold, and platinum, and it is believed that there is gold worth more than US$150 trillion lying beneath the waters. 4

Growing consumerism and an increasing demand for phones, laptops, batteries, and other electronic devices have resulted in the need to mine for more metals. Some mining and exploration companies have developed novel techniques to extract these minerals, by using ships to harvest nodules directly from seabeds or break down the mineral deposits from cobalt crusts and polymetallic sulfides. A hose then draws sediments to the surface, extracts the ore, and another process of flushing unwanted sediments back into the water will then be carried out. 5 While some studies have been conducted on the financial and environmental viability of such seabed dredging activities, there needs to be further investigation to analyse how sediment plumes can travel horizontally and vertically in the marine environment, what processing agents are contained within the discarded sediment body, and the impact of toxic chemicals used during the extraction process as well as the corresponding effects of re-sedimentation on habitats and marine species.

While there is limited scientific data available on the benthic disturbances to geographic features, preliminary findings suggest that the seabed could take many decades to recover from a dredging event. 6 In one experiment, minimal recovery was recorded 26 years after a simulated nodule extraction from an abyssal plain was carried out. 7 The disturbed marine environment had abysmal rates of repopulation, with 91% of ocean species failing to revert to numbers seen during pre-disturbed conditions.

The destruction of deep-sea habitats could make a huge impact on the diversity of species. 8 Pharmaceutical companies are conducting research into deep-sea bacteria that have the potential to kill pathogens, but these organisms are at risk of being wiped out by commercial deep-sea mining. 9 There may also be negative consequences from all the noise and light generated from mining equipment operating in an environment previously unexposed to such disturbances. Research has shown that light sources from marine vessels have the potential to damage the retinas of shrimps that live around hydrothermal vents.10

The effects of deep-sea mining are transboundary as ocean ecosystems are interconnected. The deep-sea mining process envisaged by some exploration firms has an indirect impact on the water column hundreds to thousands of metres above the seafloor. 11 Over 90% of the biosphere is found in the midwaters of the world’s oceans, and toxic discharge of chemicals at this depth will threaten the livelihoods of fisheries. 12 Waste or sediment discharge at depths of up to 1000 metres may affect species with extended deep dives like yellowfin and bigeye tuna, while the population of snappers may drop if seamounts are affected by plumes. 13 Given the vulnerability of deep-sea habitats, strict protocols need to be enforced to govern seabed dredging activities so that mining and exploration companies are compelled to act responsibly.

Established under the United Nations Convention on the Law of the Sea (UNCLOS) in 1994, the International Seabed Authority (ISA) has been tasked to protect the marine environment. While regulations for deep-sea mining have not been formally established, the ISA has since granted 30 exploration licences to countries including China, France, Germany, India, Japan, the Russian Federation, and Singapore. These licences cover about 1.5 million square kilometres of seafloor and allow companies to experiment with their extraction vehicles, in preparation for commercial deep-sea mining which may happen if ISA releases their underwater Mining Code, that regulates “prospecting, exploration and exploitation of marine minerals in the international seabed” in end-2020. 14 But ISA members have been struggling to come to a common consensus on a framework. 15 It must be stressed that due to gaps in scientific research to-date, a complete ecological assessment of deep-sea dredging activities has not been fully established.

While parametrisation and marine environmental impact assessments continue to be conducted, it is recognised that the dispersal and re-sedimentation of particulates with current deep-sea mining apparatus will definitely harm life below water and bring about irrevocable damages. Such negative outcomes from deep-sea mining fly in the face of the United Nations’ Sustainable Development Goal 14, which calls for sustainable practices to be carried out in bodies of water. If deep-sea mining is to be the future of the extractive industry, it must be clean, sustainable, and not require additional remediation work to rid it of its environmental impact. 

Contrary to belief that seabed mining would generate extensive revenues, no viable technology has yet been developed for mining gold at depth, at costs that can compete with terrestrial mines. The scientific consensus remains that economic mining of the ocean depths might still be years away. And as concerns grow over deep-sea mining activities, exploratory interests may gravitate towards traditional land-based gold mining, for which Clean Mining has a non-toxic solution that enables cyanide-free and mercury-free mining operations.


Clean Mining is part of the Clean Earth Technologies group.


[1] See, for more on the deep-sea, “The deep-sea ~ MarineBio Conservation Society,” MarineBio Conservation Society, June 11, 2020, ​​.

[2] For more on geographic features, see, Isabella *Grabski, “The Next Gold Rush: Mining in the deep-sea,” Science in the News, September 27, 2019, ​​.

[3] “The International Seabed Authority and deep-seabed Mining,” United Nations (United Nations), accessed October 8, 2020,​.

[4] Meghan Miner, “Will Deep-Sea Mining Yield an Underwater Gold Rush?,” National Geographic, May 7, 2016,​.

[5] For more on marine mineral recovery method, see, “The International Seabed Authority and deep-seabed Mining,” United Nations (United Nations), accessed October 8, 2020,​.

[6] See, for more on seabed disturbances, Isabella *Grabski, “The Next Gold Rush: Mining in the deep-sea,” Science in the News, September 27, 2019, ​​.

[7] See, for more on simulated nodule extraction experiments, “26 Years after Experimental Mining, a Seabed Ecosystem Has Yet to Recover,” DSM Observer, June 25, 2019,​.

[8] For more on deep-sea ocean species, National Oceanic and Atmospheric Administration US Department of Commerce, “How Many Species Live in the Ocean?,” NOAA’s National Ocean Service, March 1, 2018,​.

[9] See, for more on organisms that may provide pharmaceutical solutions, Isabella *Grabski, “The Next Gold Rush: Mining in the deep-sea,” Science in the News, September 27, 2019, ​​.

[10] For more on the study on shrimps, see, 1999 Robert IrionMar. 10 et al., “Deep-Sea Shrimp Blinded by Science,” Science, December 11, 2017, ​​.

[11] See, for more on the impact of deep-sea mining on midwaters, “Deep-Sea Mining Effects May Be Felt from Top to Bottom, Surface to Seabed,” IUCN, July 9, 2020,​.

[12] For more on the biosphere of midwaters, see, “Scientists Urge Caution, Further Assessment of Ecological Impacts above Deep Sea Mining,” ScienceDaily (ScienceDaily, July 9, 2020),

[13] For more on the impact of deep-sea mining on fisheries, see, “Impacts of Mining Deep Sea Polymetallic Nodules in the Pacific Ocean,” Deep Sea Mining: Out Of Our Depth, August 13, 2020,​.

[14] See, for more on ISA’s Mining Code, “The Mining Code,” International Seabed Authority, accessed October 8, 2020,​.

[15] For more on the Mining Code’s draft, see, “Draft Mining Regulations Insufficient to Protect the Deep Sea – IUCN Report,” IUCN, July 17, 2018,​.

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