New Developments in Underwater Mineral Exploration, Offshore Brazil

Metallic mineral exploration in deep water is no longer a distant reality: the project Marine E-tech is progressing via an agreement between Brazil and the United Kingdom.

Figure 1: Location of Rio Grande Rise. Image Credit: Google Maps

The mining industry razes vast areas of land and excavates deep into the Earth’s crust to extract metals and elements. Mineral resources on the planet are a finite resource, so exploring solutions aimed at supplying the growing demand for minerals is valid, even underwater.

Metallic mineral exploration in deep water is no longer a distant reality: the project Marine E-tech enables exploration of marine ferromanganese crust deposits and is progressing via an agreement between Brazil and the United Kingdom. Two primary study sights have been chosen, both are underwater mountains growing c. 3,000 meters above the seabed. The first study site is called the Tropic Seamount and is situated in the Eastern Atlantic; the second site to be studied is the Rio Grande Rise in the West Atlantic.

The Rio Grande Rise is located 1,500 km off Brazil’s southern coast. Even though it was named after the southernmost Brazilian state (Rio Grande do Sul), the Rio Grande Rise is situated in international waters.

Elements present in the ferromanganese crust layers and polymetallic nodules on the cortex of this submarine mountain, such as tellurium and selenium, are valuable for multiple industrial uses. Such elements are useful in making a variety of products including glasses and electronics; they even have potential to remove some types of skin fungus. These elements are used in solar panels, wind power turbines, electric vehicle batteries, small electronics and are combined with other elements to improve specific qualities of copper and lead alloys.

Figure 2: Polymetallic nodules, in cross-section on the left showing metallic growth rings and a complete nodule on the right. Image Credit: ISA

In addition to exploring the exploitation potential of these elements, another aim of the Marine E-tech research involves gaining a better understanding for “the oceanographic components of these deposits, which are very rare in the oceans,” says Luigi Jovane, Ph.D., a professor at the Oceanographic Institute of the University of São Paulo (IOUSP). The principal goal is to understand the origin of these polymetallic deposits, formed millions of years ago.

“We want to investigate the elemental composition of the Rio Grande Rise and discover why these elements grow here,” Jovane said. “We are working with several hypotheses. One is biogenesis or the notion of living stones, and the idea that microorganisms present in the stones help fix the metal onto nodules and crusts. Another hypothesis is that these metals are the result of chemical reactions alone.”

A collaborative agreement between Fundação de Amparo à Pesquisa do Estado de São Paulo – The São Paulo Research Foundation (FAPESP) and the Natural Environment Research Council (NERC) has made such interdisciplinary projects and research among experts and teachers at the IOUSP possible.

The Marine E-tech expedition to the Rio Grande Rise, scheduled for 2017, is part of a larger project called the Security of Supply of Mineral Resources program (SoS MinErals), funded by NERC, UK; the Engineering and Physical Science Research Council (EPSRC); FAPESP, Brazil.

Figure 3: A remotely-operated vehicle (ROV) working in the area of Río Grande. Image Credit: Nautilus Minerals

The first Marine E-tech expedition, that lasted six weeks from Oct. 29-Dec. 9, 2016 was headed by the National Oceanography Center (NOC) in the UK. It successfully explored ferromanganese crust on the Tropic Seamount, south-west of the Canary Islands, using NOC’s scientific research vessel the RRS James Cook and deep sea equipment. The expedition sought to discover and research new resources of rare elements such as cobalt and tellurium, essential for renewable energy technologies. Some of these elements are highly concentrated in ferromanganese seafloor deposits. The highest levels of enriched tellurium are found in seafloor ferromanganese crusts formed on some underwater mountains. NOC actively investigates the origin and formation of these crusts in addition to studying the potential environmental impacts that could result from extractive processes.

An objective of the SoS MinErals project is to assess the potential for recovery of technology-based elements using low-carbon extraction technologies, such as processing with ionic liquids. The role of sustainability in the extraction of these kind of deposits is a key concept.

The vessel to be used in the expedition to the Rio Grande Rise will be accompanied by advanced deep-water technology and a remotely operated vehicle (ROV) capable of operating at water depths up to 5,000 meters. The data from both expeditions will be recorded at high spatial and temporal resolutions.  Though this expedition is a scientific research investigation, evaluation of the mining potential at these sites is possible by quantitative resource analysis of data acquired during the expedition.  

Operations at the site will include the installation of current measurement devices and the collection of data from vertical profiles of salinity and temperature to depths of more than 4,000 meters. Water and sediment samples will also be collected for laboratory analysis. HR Wallingford will provide the instruments and analyze the collected data. It is anticipated that this study will help to establish best practices for the extraction of deep ocean minerals from seamounts and thus minimize harmful impacts to marine ecology.

Environmental Impact

The project also aims to evaluate the environmental impact potential future marine mining of these deposit types could incur.

“We’re going to estimate the degree of biodiversity of this mountain that rises more than 3,000 meters high from the seabed” 4,200 meters from the seabed and is more than 3,000 meters high,” said Paulo Sumida, a professor at the IOUSP. “Recovery after mining on land is relatively quick, thanks to reforestation, for example. “However, it is slower in deep water. There are records of corals older than 800 years  and fish that take more than 50 years to reach maturity. The impact in an environment such as this is much more harmful and some species do not recover in a hundred years.”

A well studied submarine area that could be used as an analogue for the Rio Grande Rise is the Clarion-Clipperton Zone (CCZ). Situated in the Pacific, this is another complex underwater landscape with abundant polymetallic nodules that has been divided into licenced areas for study and exploration by the International Seabed Authority (ISA). Some of the CCZ will have areas of permanent preservation after the discovery of the fragile ecosystem that exists around polymetallic nodule deposits here.

During Marine E-tech’s study of the Rio Grande Rise, the NOC will provide two underwater remotely operated vehicles and will endeavour to minimize environmental damage during the collection of materials for research.

Mineral Rush

Although it is not a gold rush, the exploration of rare earths and metal ores in deepwater environments has arouses the interest of companies operating in the offshore and minerals sectors. The ISA has already granted 26 licenses totalling 1.2 million square kilometers of seabed in the Atlantic, Indian and Pacific oceans combined.

Offshore Brazil, licences located outside Brazilian territorial waters in the international seabed area at the Rio Grande Rise have been assigned to the Company for Mineral Resources Research (CPRM).

“We understand that there is a potential, mainly for the electronics industry, which often doesn’t develop certain technology due to the absence or insufficiency of some kind of mineral, that would make production too expensive or unfeasible,” Jovane said. “I think this will interest more and more companies that will begin to create technology with a mineral that is going to be available in 30 years.”

Beatriz Borges is a Brazilian journalist.

María Victoria Ennis is an Argentine journalist.

This article was prepared by Universidad Nacional Del Centro De La Provincia De Buenos Aires (UNCPBA). Coordinators for Earthzine: Gerardo Acosta and Mª Eugenia Conforti; translator: Luciano Banchio.

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