The HMS Challenger Expedition of 1872–76, having recovered polymetallic nodules from the deep seafloor for the first time, ensured that these strange objects have become the signature marine mineral. Consequently, the economic value of manganese nodules became a firm focal point. The scientists on board the steam corvette estimated the value of the range of metals contained in the nodules but disregarded the considerable costs of recovery and refining. This estimate led to a “gold rush” mentality at that time and, ultimately, led to the development of the UN Convention on the Law of the Sea (UNCLOS) to ensure that the anticipated wealth would be shared between developed and developing nations.
Polymetallic nodules are lumps of material that range in size from just a few millimetres to tens of centimetres and are found in the abyssal areas of the oceans basins of the world. Known deposits are found in various quantities around a water depth of 3,500 to 6,000 metres. They lay on a relatively flat seafloor of soft sediment in a large surface area. They mainly contain manganese, nickel, cobalt and copper. However, a number of other valuable elements such as REE are also present. Techniques for harvesting polymetallic nodules were first tested during the 1970s.
In 2001, the International Seabed Authority (ISA) granted several national and industrial groups of pioneer investors, exclusive 15-year exploration contracts for tracts of the region of the most prospective polymetallic nodules. The area, referred to as the Clarion and Clipperton zone, is located in the eastern equatorial Pacific Ocean.
On 14th of January 2013, the International Seabed Authority and Global Sea Mineral Resources NV (GSR) signed a 15-year contract for prospecting and exploration for polymetallic nodules. Under the contract, GSR will have exclusive rights for exploration for polymetallic nodules over 76,728 square kilometers of the seabed in the eastern part of the Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean.
Since September 2014, GSR NV has been integrated into DEME Concessions NV.