Introduction

demand of minerals
1.1 Nodules *what is that?
Found at depths between 4000 and 6000 meters(Potential econ impacts article), the manganese-nodule fields, represent a potential source of metals, in the developing mining sector.  The estimates indicate a greater mass and concentration of metals, in these deposits, than in the land-based reserves. The research regarding the exploitation, its profitability and the possible environmental impacts, that would supervene, are still heavily researched.  
The ellipsoidal concretions,  formed in the sediment, in the deep sea, had been first  discovered, at the end of the 19th century, in the Kara Sea, located in the Siberian region of the Arctic Ocean. Afterwards, due to the further exploration, it was determined that these polymetallic nodules are spread in most of the world's oceans, predominately in international waters(ISA pamphlet).   
The first chemical and physical description of the polymetallic nodules was published by John L. Mero, who also one of the first scientist who proposed treating these marine deposits as a potential economically feasible  resources, in the future.   (Mero 1977Mero, J. L. 1977. Chapter 11 economic aspects of nodule mining. In Marine manganese deposits, ed. by G. P. Glasby vol. 15, 327–55. Elsevier Oceanography Series 15. Amsterdam: Elsevier.[Crossref], , [Google Scholar]).  The high metal concentrations, with an average of  25%-30% manganese,  6% iron, 5%  silicon,  3% aluminium, 1.25%-1.50% nickel, 1-1.40%copper and 0.20%-0.25% cobalt,  combined with traces of Ca, Na, Mg, K, Ti and Ba(potential econ impacts article &   R. Hesse paper),  and the relatively high abundance, in  the north central zone of the Pacific Ocean,  between Hawaii Islands and the Peru basin, and the center of the north Indian Ocean(Hesse),  opened a new interest in the exploration of these promising deposits, after the publication of J.L. More  Ocean-floor Manganese Nodules (1962) and CHAPTER 11 ECONOMIC ASPECTS OF NODULE MINING   (1977).  The average magnitude of the total metallic resources varies in literature between  670 million tons* to 1.5 trillion (Hesse).
he nodule size distributions suggest that the ratio of the nodule burial rates to growth rates systematically decreases over the same range (1.95 to 1.14 nodules buried per 1 cm of growth per m2 of seabed area).   ->
Preliminary analysis of exploration data from pacific deposits of manganese nodules Charles L. Morgan , Jean A. Nichols , Bruce W. Selk , John R. Toth & Charles Wallin
 
Even if 70% of our world’s surface is covered by water, the deep-sea is in many ways the last great unexplored frontier on the Earth. However, the oceans hold a veritable treasure of valuable resources. Vast areas of ocean seafloor are covered by loose, metal-bearing nodules about the size of potatoes. Although seafloor manganese nodules (SMnN) were discovered by scientists of the HMS Challenger expedition (1872–76), it was Mero who advocated these deposits as a possible commercial source of metals in the early 1950s (Mero 1977Mero, J. L. 1977. Chapter 11 economic aspects of nodule mining. In Marine manganese deposits, ed. by G. P. Glasby vol. 15, 327–55. Elsevier Oceanography Series 15. Amsterdam: Elsevier.[Crossref], , [Google Scholar]). Since then, SMnN have been in the focus of numerous research projects, especially in the 1970s and 80s (Knodt et al. 2016Knodt, S., T. Kleinen, C.Dornieden, J. Lorscheidt, B.Bjørneklett, and A. Mitzlaff. 2016. Development and engineering of offshore mining systems - State of the art and future perspectives. Houston, Texas, USA: Offshore technology conference. [Google Scholar]). “The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U.N. Convention on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining.” (Glasby 2002Glasby, G. P. 2002. Deep seabed mining: Past failures and future prospects. Marine Georesources & Geotechnology 20 (2):161–76. doi:10.1080/03608860290051859[Taylor & Francis Online][Web of Science ®], , [Google Scholar]) With the rising metal prices in 2006–2012, the interest in deep-sea mineral resources experienced a renaissance.
Seafloor manganese nodules contain primarily manganese, but also nickel, cobalt, copper, and rare earth elements (Hein 2013Hein, J. R. 2013. Manganese nodules. In Encyclopedia of marine geosciences, ed. by J.Harff M. Meschede S. Petersenand J. Thiede 1–7. Dordrecht: Springer Netherlands. [Google Scholar]). Those deposits may be an important future source of supply for the Western European automotive, metal and electrical industries to sustain the expansion of renewable energies and climate (Wiedicke et al. 2015Wiedicke, M., T. Kuhn, C.Rühlemann, and A. Vink. 2015. Schwarz-Schampera: Deep-sea mining–A future source of raw materials. Mining Report 151. [Google Scholar]; Hein 2016Hein, J. R. 2016. Manganese nodules. In Encyclopedia of marine geosciences, ed. by J.Harff M. Meschede S. Petersenand J. Thiede 408–12. Encyclopedia of earth sciences series. Dordrecht: Springer Reference. [Google Scholar]; Marscheider-Weidemann et al. 2016Marscheider-Weidemann, F., S.Langkau, T. Hummen, L.Erdmann, L. A. Tercero Espinoza, G. Angerer, M. Marwede, and S.Benecke. 2016. Rohstoffe für Zukunftstechnologien 2016: Auftragsstudie. DERA Rohstoffinformationen 28. Hannover: DERA. [Google Scholar]). The International Seabed Authority (ISA) is the organ which is entitled to act on behalf of mankind and whose responsibility is to organize and control all mineral-related activities and resources in “the Area” beyond the limits of national jurisdiction (United Nations 1982United Nations. 1982. United Nations convention on the law of the sea: UNCLOS.http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf(accessed November 18, 2016). [Google Scholar]). In that time the EU funded several projects related to deep-sea mining as a part of their research and technological development program. The most recent projects are MIDAS (2013–2016), Blue Mining (2014–2018), and Blue Nodules (2016–2020).
While today’s mine planning of land-based ore deposits follows methods which are well established (Darling 2011Darling, P. 2011. SME mining engineering handbook, 3rd ed. Englewood: Society for Mining, Metallurgy, and Exploration. [Google Scholar]), mining standards for the deep-sea have yet not been established. The identification of (potentially) mineable seafloor area is reliant on a project’s exploration data. Kuhn, Rühlemann, and Wiedicke-Hombach (2012Kuhn, T., C. Rühlemann, and M.Wiedicke-Hombach. 2012. Developing a strategy for the exploration of vast seafloor areas for prospective manganese nodule fields. In Marine minerals: Finding the right balance of sustainable development and environmental protection, ed. by H. Zhou and C. L. Morgan 9. Shanghai. [Google Scholar]) “[ … ] suggest that hydroacoustic backscatter data in conjunction with slopes less than 3° are indicative of prospective Mn nodule fields.” This approach is further developed and refined to identify potentially mineable areas and to define mining fields. Inspired by the high-tech farming industry, additional information is derived regarding mineable proportions, field sizes, and field characteristics. Suitable mining patterns can then be assessed using production key figures (PKFs). Thus, this paper contributes to the setting of requirements and the validation of assumptions for future mine planning in the deep-sea.
The German license area in the eastern part of the Clarion Clipperton Zone (CCZ; 11°00′N, 118°00′W; Figure 1) encompasses a total of 75,000 km2. The license area is divided into two regions with 17,000 km2 in the central part and 58,000 km2 in the eastern part of the Pacific Nodule Belt (Rühlemann et al. 2011Rühlemann, C., T. Kuhn, M.Wiedicke-Hombach, S. Kasten, K.Mewes, and A. Picard. 2011. Current status of manganese nodule exploration in the German license area. The proceedings of the ninth (2011) ISOPE ocean mining symposium, ed. Maui, Hawaii, USA: The International Society of Offshore and Polar Engineers (ISOPE), 168–73. [Google Scholar]). For spatial analysis, exploration data of the eastern German exploration license (E1) have been used. A vessel-based bathymetric survey was executed by the BGR using the swath echo sounding system EM 120 to receive information on the geological properties of the seafloor (Kuhn, Rühlemann, and Wiedicke-Hombach 2012Kuhn, T., C. Rühlemann, and M.Wiedicke-Hombach. 2012. Developing a strategy for the exploration of vast seafloor areas for prospective manganese nodule fields. In Marine minerals: Finding the right balance of sustainable development and environmental protection, ed. by H. Zhou and C. L. Morgan 9. Shanghai. [Google Scholar]). “The seafloor is characterized by extensive deep-sea plains interspersed with elongated NNE-SSW oriented horst and graben structures that are several kilometers wide, tens of kilometers long and on the order of hundred meters high [ … ] An analysis of the topography shows that in ∼80% of the license area the slope of the seafloor does not exceed 3°.” (Rühlemann et al. 2009Rühlemann, C., U. Barckhausen, S. Ladage, L. Reinhardt, and M.Wiedicke eds. 2009. Exploration for polymetallic nodules in the German license area. Chennai, India: International Society of Offshore and Polar Engineers. [Google Scholar])
In the framework of the Blue Mining project, a potential mine site within E1 was studied (Rahn 2016Rahn, M. 2016. Deliverable 3.11: Deposit models. Public report submitted to the EU Commission within the 7th framework programme (GA No. 604500).http://www.bluemining.eu/downloads/(accessed July 26, 2016) [Google Scholar]). Due to its size (255 km2) the exemplary mine site is assumed to represent the characteristics of a potential mining field (Table 1). “The study area is dominantly flat, 94% of the area exhibit a slope of less than 3°, only 6% of the area has a slope larger than 3° with a maximum of 29.86°. The nodule coverage is on average 16.51 kg/m2 with a minimum of 10.29 kg/m2 and maximum of 21.31 kg/m2 (dry weight). The total tonnage of nodules is about 4 Mt with 113,812 t for copper, nickel, and cobalt tonnage and 1,171,000 t for manganese.” (Rahn 2016Rahn, M. 2016. Deliverable 3.11: Deposit models. Public report submitted to the EU Commission within the 7th framework programme (GA No. 604500).http://www.bluemining.eu/downloads/(accessed July 26, 2016) [Google Scholar])