Metal Demand and Deep-Sea Mining (original) (raw)

2021, Advances in Oceanography & Marine Biology

The world's population, today numbering more than 7.8 billion people, is projected to increase to 8.5 billion in 2030 and peak at 11.2 billion by 2100. The world economy is expected to grow at an annual average rate of around 2.6% between 2016 and 2050. The growing population, the increase in GDP levels and the consumption patterns of modern society lead to a higher need for resources. The global ocean covers approximately the 71% of our planet's surface. It has an enormous importance due its economic values and the wide range of ecosystem services. Nowadays, it is well acknowledged that the Ocean and its resources are vital for tackling the several challenges that the Earth faces in the decades ahead. The depletion of terrestrial mineral deposits and the continuous rise of the demand for critical metals, arouse the interest for the exploration of marine mineral resources. Seabed mining is an emerging industry of the blue economy. Advances in deep-sea technology make seabed mining commercially viable. Critical metals [1] are crucial for emerging green and artificial intelligence technologies and achieving the targets of sustainable development. Metals, like manganese, iron, cobalt, copper, nickel, zinc, lithium, titanium, tellurium and the rare earth elements (REE), are hosted in various seabed resources [2]. Metal mineral resources are deep-sea polymetallic nodules, cobalt-rich ferromanganese crusts, seafloor massive sulphides, marine phosphorites, REY-rich muds, as well as placer deposits [3-9]. Significant abundances of nodules occur in four abyssal areas, the Clarion-Clipperton Zone in the Pacific Ocean, the Peru Basin in the Eastern Pacific Ocean, the Penrhyn basin very near the Cook Islands in the South Pacific Ocean, and the central Indian Ocean, at water depth ranging from 3,500 to 6,500m. Polymetallic nodules consist mainly of manganese, iron, copper, nickel and cobalt along with other interest elements like zinc, lithium, molybdenum, titanium and rare earth elements plus yttrium (REY). Up to 19% of the known polymetallic nodules are in Exclusive Economic Zones [10]. Cobalt rich ferromanganese crusts with a high mining potential are found mainly in water depths from 800 to 2,500 m, especially in the Central Pacific Ocean called the "Prime Fe-Mn Crust Zone (PCZ). Additional exploration areas are the NE Atlantic margin and the Indian Ocean [2,11,12]. Ferromanganese crusts have a high enrichment in cobalt, tellurium, nickel, molybdenum and REY. Up to 54% of the known crust are in Economic Exclusive Zones [10]. Seafloor massive sulphides (SMS) are formed on hydrothermal sites, along mid-ocean ridges, and especially on the East Pacific Rise, the Southern East Pacific Rise, the North Pacific Rise and the Mid-Atlantic Ridge. Seafloor massive sulphides are found at depths varying from 1,500 to 3,500 m. Areas