On the metal contents of ocean floor nodules, crusts and massive sulphides and a preliminary assessment of the extractable amounts
Anna Hulda Olofsdottir1, Harald Ulrik Sverdrup1, Kristin Vala Ragnarsdottir2
1Earth Sciences, University of Iceland, Iceland; 2Industrial Engineering, University of Iceland, Iceland
The metal contents of ocean floor nodules, crusts and massive sulphides and an assessment of their commercial extractability was conducted with respect to the metals iron, manganese, copper, nickel, cobalt, molybdenum, platinum, gold and silver. We found that, according to the current literature, significant metal amounts are present and located in mainly 5 limited geographical regions of the ocean floor: Northwest Pacific, Southwest Pacific, Pacific Penrhyn Basin, Indian Ocean and two major regions in the Atlantic Ocean. Most of the tonnage of the studied metals are located at great depth, from 1 km to more than 4 km depth, involving huge technological challenges. Only a smaller fraction (5-25%) of the detected amounts can be considered to be extractable under the most favourable of conditions. We found that the land-based metal resources appear to be more readily available for extraction and that they constitute the major part of the available resources in quantitative terms, with the exception of perhaps cobalt. Despite huge optimism in the field, no profitable commercial operation has yet been started. Considering the challenges of deep seafloor mining, we conclude that based on ore grade to metal price evaluation, that only cobalt or silver may be interesting on a commercial level. This mining will have by-products of copper, molybdenum and nickel.