Marine polymetallic sulphides (INDEX) – Germany’s exploration license in the Indian Ocean

Country / Region: Indian Ocean

Begin of project: January 1, 2011

End of project: May 5, 2030

Status of project: March 18, 2022

Inactive polymetallic sulphide slot in the GAUSS-sulfidfield on the ocean floor, Indian Ocean Source: BGR

The German industry depends on the import of metallic commodities to 100%. The tight international markets for base and special metals are quite competitive despite high recycling rates for some of the commodities. The base metals include copper, zinc, lead, tin. Precious and special metals like gold, silver bismuth, selenium, tellurium, gallium or indium represent significant components in electronic parts of modern technological devices such as in the photovoltaic industry and its solar panels, and in devices of state-of-the-art telecommunication and computer industries. Massive sulphide deposits are the prime source of these metals. This deposit-type is mined worldwide on land today but form since at least 3.400 Mio years on ocean floors. These deposits account for more than 50 % of the total global zinc and lead production. They also produced 7 % of the total global copper and 18 % of silver and accounted for significant shares in the gold and trace metal production.

In the light of increasing commodity prices a dynamic global process has started to explore potential marine resources. There exist more than 400 locations of metalliferous fluid discharge and mineral precipitations in the world oceans. More than 100 locations form metal-rich chimneys and black smoker-type mineralisation from high temperature fluid discharge. The chimneys represent the seafloor precipitation of potentially rich metal sulphide ore bodies in the underlying upper oceanic crust. These hydrothermal deposits occur along world’s oceanic volcanic ridges. About 65 % of the deposits occur along mid-ocean ridges, spreading centers in the world’s oceans with a total length of more than 60 000 km. These spreading centers continuously form new oceanic crust. The number of worldwide marine occurrences, the understanding of the potential sizes and metal resources of these deposits from land mining, and the increasing global interest in the use of marine resources resulted in the establishment of regulations by the International Seabed Authority (ISA). The ISA is one out of three institutions of the International Law of the Sea. The regulations offer the opportunity to acquire exploration licenses in the international seas (“the area”) and shall ensure the sustainable protection of the marine environment. Since July 2011 private companies and countries like China, Russia, France and South Korea applied for and acquired exploration licenses from the International Seabed Authority and carry out mineral exploration. In December 2013, BGR in order for the Federal Ministry for Economy and Energy (BMWi) submitted an application for an exploration license for polymetallic sulphides in an area of 10 000 km², divided in 100 sulphide blocks each 10 x 10 km in size, in the southwestern Indian Ocean. In July 2014 during the annual meeting of the International Seabed Authority (ISA) the German application was adopted. With the signed contract in early 2015, BGR has permission to start detailed exploration program in the license area southeast of Madagascar. The program includes the outline of potential ore deposits and a resource assessment but also extensive and detailed base line studies for the sustainable protection of the marine environment. The license contract has a fifteen years lifetime and may allow the application for a subsequent mining license. The exploration license aims at the identification of inactive polymetallic sulphide deposits, formed at former discharge zones of hot hydrothermal fluids on the ocean floor (“black smoker”), by modern exploration techniques.

In addition to the existing activities for the exploration license for manganese nodules in the Pacific Ocean, BGR is continuing its exploration program on polymetallic sulfides started in 2011. The expedition INDEX2015 in the Indian Ocean started in late 2015 with the Dutch research vessel MV PELAGIA. The cruise targeted on the identification of formerly active polymetallic sulfide areas and fields along the southern Central Indian Ridge with the help of modern exploration techniques.
Among other geophysical methods (CSEM, Magnetics, Sidescan), BGR used again a new deep-towed sled equipped with sensors to determine indicative parameters from the surroundings of the sulfide occurrences as well as environmental data for ongoing base line studies from the water column. Base line studies of the biodiversity and settling density of seafloor organisms were an integral part in this cruise as well as during all the other cruises.
Part of this environmental program was covered by biologists from the German Center for Marine Biodiversity at the Senckenberg Institute in Wilhelmshaven. Another partner was the Canadian Scientific Submersible Facility (CSSF), which with “ROPOS” supplied a remotely operated vehicle (ROV) for detailed subsea sampling. Scientists and experts from Kiel, Bremen, Hamburg and also Sudbury/Canada and Seattle/US joined the cruise. In addition, since 2015, twelve trainees from different countries (Egypt, Nigeria, Ghana, Argentina, Thailand, Singapore, India, Mauritius) have been familiarized with the exploration work during several cruise participations as part of an recommendation of the ISA.
In January 2016, the marine cruise took place on board a French research vessel. Target of this expedition was the exploration of the southern part of southeast Indian Ridge, which is situated much further to the south. With the early season cruise, we expected to be able to monitor possible seasonal changes in the biomass distribution. On the other hand, we hoped for calm and stable weather and working conditions in this southernmost area.

The latest ship expedition (INDEX2021) to the German license area ended at the end of 2021. During the expedition with the Dutch research vessel "Pelagia", the three-dimensional extent of the raw material deposits in the seabed in the southernmost part of the license area was recorded with the help of geophysical investigations. The geological work focused on the use of a newly developed drilling rig. From an unmanned submersible, drill cores up to one meter long were taken from the seafloor in a targeted manner. This not only provided proof of the technical functionality of the device, but also demonstrated that the drilling device can be used to obtain the information required to evaluate the deposits on site (in-situ) with minimal environmental impact. Another part of the expedition was also devoted primarily to environmental work. For example, five moorings were successfully recovered from water depths of up to 4,000 meters after two years of collecting valuable long-term environmental data.

Information, pictures and video material from cruise INDEX 2013 can be found in the INDEX2013-Diary

Information and photos from cruise INDEX 2016

Project contributions:

• Cruise MSM59/1 - INDEX 2016_2
• German Exploration License in the Indian Ocean (INDEX) - Environmental Studies by BGR