Deep-sea polymetallic nodules are considered to be an important potential resource for nickel, cobalt, copper and manganese. The research has showed that they contain a large variety of other metals, including molybdenum, zinc, zirconium, lithium, platinum, titanium, germanium, yttrium, and REEs, which increased the nodules combined value as an alternative supply for expanding economies, high technology and emerging green energy technologies. The highest nodule abundance (more than 10 kg/m2) with the high average percentage of metals (at least 2.5 % content for Ni+Cu, 0.2% Co, 30% Mn, 0.15% Zn, 0.07% Mo, etc.) was found at seafloor in the eastern equatorial Pacific (Clarion-Clipperton Fracture Zone). Within the recent decade, the International Seabed Authority (ISA) granted several national and multinational entities the exclusive 15-years contracts for polymetallic nodules exploration in the claimed areas, each covering 75,000 km2. The commercial viability of nodule mining has to be established, but the size of deposits, the grades of several metals contained in nodules as well as promising trends in metals market continue to motivate contractors to carry out their exploration activity.
Ocean Mining for Environment
Polymetallic nodules are a source of metals for engineering conducive to the environment. Modern devices are based on highly innovative technologies. They are impossible to build without the use of copper, nickel, cobalt, manganese and other metals, which are found in the nodules.
Copper as well as its alloys commonly accompany us throughout all civilizations. Certain uses of it, such as for example plumbing, corrosion-resistant coating or food industry are obvious and known to everyone. Copper is, however of considerable importance in the development of emerging green technologies. It has excellent characteristics of current conduction, hence its great role in energy generation for a modern but sustainable society. Unconventional methods of the renewable energy production require development of innovative technologies for collection and processing of various forms of energy. Generating the same amount of energy from a modern wind turbine, compared to a power industry based on fossil fuels, requires the application of even dozen tons of copper or even more. The percentage of copper in the terrestrial deposits decreases, therefore the high concentration of this metal in nodules provides great potential for the efficient and sustainable exploitation of subsea deposits.
Nickel is used primarily for the production of corrosion resisting steels, protective and ornamental coatings and special super-alloys used in efficient, cutting-edge and cost-effective engines with low emissions and low specific fuel consumption. The future use of nickel is primarily in production of environmentally friendly nickel-metal hydride batteries. These innovative batteries do not contain toxic cadmium compounds, contrary to rechargeable nickel-cadmium batteries, and have very high energy density. Nickel foams are used in the production of alkaline fuel cell (AFC). The AFC is one of the most complex and highly-developed fuel cell technologies. They use solely hydrogen and pure oxygen to produce electricity, water and heat. Alkaline fuel cells based on the nickel foams is technology which completely fulfils expectations of a future sustainable energy conversion technology. Manganese is an element without which it would be impossible to manufacture durable and lightweight steel used, for example, in the engineering of means of transport. Its use greatly reduces fuel consumption, CO2 emissions and makes the high energy efficiency operations possible. Potassium permanganate (Potassium permanganate) is applied in cutting edge external water treatment processes. In the situation of its universal accessibility, it is important for the development of civilization in countries with restricted access to water.
Cobalt is a component of alloys resistant to very high temperatures, which enhances the progress of low-carbon technologies with high thermal efficiencies. About 50% of the cobalt production is found in rechargeable batteries, technology for a sustainable future. Moreover, cobalt is the innovative material used for the sophisticated construction of catalytic converters, applied in the process of hydrogen generation.
Deep ocean mining provides an unconventional, forward-thinking, technologically advanced sourcing of raw materials for environmentally friendly technologies. In the case of ocean mining there is no risk of disruption of social structures in the mined areas. Such a risk is always present when the mining operations are on land. The land-based mines, especially the open-pit ones, occupy a large area and interfere in the social and environmental system. Changes may even lead to regional loss or degradation of the local cultural societies. This threat does not occur in the case of the highly-advanced ocean mining. On the contrary, in accordance with the planned mining licensing policy, cooperation between the IOM and the UN’s International Seabed Authority may include a hybrid social business model (Hybrid Social Business – HSB). The HSB business model is based on the benefits for the mankind, a positive social impact and promoting progressive, sustainable human development programs.
Another vitally important factor, weighting in favour of the deep ocean nodules mining, is that the deposits lie directly on the seabed. There is no need for conducting such devastating operations as pre-strip.
Ocean deposits are of polymetallic-type with greater metal contents than the terrestrial deposits, which yields significantly more advantageous extraction efficiency. In case of terrestrial deposits, the mean values of copper content in the ore are now at about 0.5%, whereas in the polymetallic nodules there is twice as much of it. The deposits of lateritic nickel ores are mainly located in the equatorial belt, so the development of mines often leads to degradation of equatorial rainforests.
In case of innovative ocean mining technology, the engineering methods will be more advanced and efficient than the usual ones. The use of vessels and platforms ensures high efficiency of the process. After completion, the project provides one of the most advanced, optimal possibilities for reuse or recycling of materials.