Breakthrough Solutions for the Sustainable Exploration and Extraction of Deep Sea Mineral Resources

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Publications

Deep-Sea Mining: a Manageable Necessity or a Curse?

Publication . Barriga, Fernando J A S

The dependence of modern societies upon critical raw materials (nearly all metals) is overwhelming. Some believe that demand is growing faster than offer, not only because of geological availability but also for political and economic reasons. For these reasons it is imperative to consider new sources for raw materials.The seafloor stands as a likely candidate. We must create readiness now to be prepared when the need comes. One of the greatest fears is the environmental cost involved in mining the deep seafloor. However, the mining industry no longer deserves its partially not favorable reputation. We need both the resources and the environment. And nIMBY (not In My Back Yard) will not help.

2018-10Book part

Open access

Ocean-Floor Sediments as a Resource of Rare Earth Elements: An Overview of Recently Studied Sites

Publication . Milinovic, Jelena; Rodrigues, Francisco J. L.; Barriga, Fernando J A S; Murton, Bramley J.

The rare earth elements (REE), comprising 15 elements of the lanthanum series (La-Lu) together with yttrium (Y) and scandium (Sc), have become of particular interest because of their use, for example, in modern communications, renewable energy generation, and the electrification of transport. However, the security of supply of REE is considered to be at risk due to the limited number of sources, with dependence largely on one supplier that produced approximately 63% of all REE in 2019. As a result, there is a growing need to diversify supply. This has resulted in the drive to seek new resources elsewhere, and particularly on the deep-ocean floor. Here, we give a summary of REE distribution in minerals, versatile applications, and an update of their economic value. We present the most typical onshore methods for the determination of REE and examine methods for their offshore exploration in near real time. The motivation for this comes from recent studies over the past decade that showed ΣREE concentrations as high as 22,000 ppm in ocean-floor sediments in the Pacific Ocean. The ocean-floor sediments are evaluated in terms of their potential as resources of REE, while the likely economic cost and environmental impacts of deep-sea mining these are also considered.

2021-01-30Journal article

Open access

XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer

Publication . Milinovic, Jelena; Dias, Ágata Alveirinho; Janeiro, Ana I.; Pereira, Manuel F. C.; Martins, Sofia; Petersen, Sven; Barriga, Fernando J A S

The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat > 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time.

2020-02-12Journal article

Open access

Mineração sustentável e responsável em ambiente marinho profundo

Publication . Barriga, Fernando J A S

Verifica-se presentemente um aumento acelerado da procura e consumo de recursos metálicos, muitos deles críticos, incluindo terras raras, cobalto, níquel, tungsténio, molibdénio, cobre, titânio, nióbio, platinídeos, índio, gálio, telúrio e muitos outros. A sociedade em geral mal se apercebe deste facto, alimentado pelo crescimento da população e sobretudo pelo aumento generalizado do poder de compra, e o concomitante crescimento do consumo de bens de alta tecnologia. A chamada economia circular terá de continuar a ser alimentada por mineração. A situação é particularmente grave para a UE, pois nela produzem-se apenas 5% dos recursos minerais utilizados pela indústria dessa mesma UE. Por este motivo, aumentou muito a procura de novas fontes de matérias-primas minerais, nomeadamente alvos a grande profundidade nos continentes, o Árctico, e os fundos marinhos, destacando-se estes últimos, onde são já conhecidas vastas quantidades de recursos. Mais que partir apressadamente para mineração sub-oceânia profunda em larga escala, precisamos de prontidão, o que implica, entre outras condicionantes, conhecer melhor o ecossistema. À ciência compete indicar o caminho, à indústria adoptar as descobertas científicas, à governança criar o quadro legal, e fazê-lo cumprir. A primeira regra terá de ser sempre “as operações ilegais ou não reguladas têm de ser encerradas”. Urge criar “mineração azul”, que respeite o ecossistema, da mesma forma que necessitamos de pescas e agricultura sustentáveis. Há bons exemplos a seguir, com relevo para o da Noruega. Sem prejuízo da necessária mudança de mentalidades (com menos consumismo), não queremos escolher entre indústria e ambiente, queremos ambos.

2019Book part

Open access