Seabed search for metals surging ahead

28.06.2017
Exploring for minerals on the ocean floor has been under way in international waters for more than 15 years. Interest in these resources is also growing in Norway.

| Harald Brekke, senior geologist, NPD

Parts of the international ocean floor covered by exploration contracts. Areas with manganese nodules, manganese crusts and sulphides are framed by thick lines in blue, green and red respectively. The thin yellow and pink lines show the 200-nautical- mile boundaries of the coastal states and their proposed continental shelf boundaries respectively.

Parts of the international ocean floor covered by exploration contracts. Areas with manganese nodules, manganese crusts and sulphides are framed by thick lines in blue, green and red respectively. The thin yellow and pink lines show the 200-nautical- mile boundaries of the coastal states and their proposed continental shelf boundaries respectively.

 

The presence of metallic seabed minerals in the world’s oceans has long been known. In some areas, these accumulations are of a size which may make them commercial – and thus to be regarded as ore deposits.

These seabed resources were a key driving force behind negotiations on the UN International Law of the Sea treaty in 1973-82, which now regulates the rights to exploit them.

A total of 27 active exploration contracts have been awarded for international sea floor areas, split between the three types of mineral deposit.

These are manganese nodules, manganese crusts and sulphides. Each of them in turn contains a number of metallic elements and lies in water depths of 1 500-6 000 metres.

Under the UN Convention on the Law of the Sea (Unclos), a coastal state controls the resources on and under its whole continental margin – even where this is extends further than 200 nautical miles from land.

The convention defines this area of national jurisdiction as the coastal state’s continental shelf – in other words, a legal rather than scientific definition of the term.

It means that the NCS is not confined to the relatively shallow areas where oil and gas are found. It also includes waters several thousand metres deep and far from land, where exploring for other types of resources could be relevant.

 

Quantities

Found on soft seabeds in the deep ocean, manganese nodules contain large amounts of manganese and iron with smaller quantities of copper, nickel, cobalt, titanium and platinum.

Manganese crusts also consist largely of manganese and iron, plus titanium, cobalt, nickel, cerium, zirconium and rare earth elements (REEs). They grow as laminated deposits on bare bedrock exposed at the seabed in water depths of 1 500-3 000 metres.

Sulphides primarily comprise lead, zinc, copper, cobalt, gold and silver, and are linked to hot springs in volcanic spreading ridges beneath the oceans where “black smokers” form.

These vents continue to spew out hot material for several thousand years before dying out and leaving behind mounds which contain the bulk of the sulphide ore resources.

 

Deep resources. The area showing manganese crust on the Vøring Spur, where samples were acquired in 2013.

Deep resources.
The area showing manganese crust on the Vøring Spur, where samples were acquired in 2013.

 

Sought

Such resources have been sought in the international parts of the ocean seabed for more than 15 years under contracts awarded by the International Seabed Authority (ISA).

The first of these areas went to seven pioneering investors in the 1990s, but their contracts only came into force in 2001 when exploration regulations for manganese modules were put in place.

Little happened until 2012, when the number of applications for the contracts suddenly rose substantially and remained stable for the next three-four years.

The jump in the number of applications coincided with the completion of the regulations governing the search for sulphides and manganese crusts.

It also occurred at a time when China was becoming the monopoly supplier of a number of strategic minerals which are important for introducing “green” technology.

Manganese crusts are expected to be a future source of such strategically important metals, including REEs.

 

 

Anticipated extent of seabed minerals on the NCS.

 

Copper

Moreover, the world’s copper reserves on land – put at roughly 720 million tonnes by the US Geological Service (USGS) – appear to be running out.

They will last for only 40 years at today’s level of consumption, but demand is expected to rise substantially in the next few years in response to green technology needs.

That gives a much shorter timeframe for identifying further supplies. In that context, the USGS has put global copper resources in manganese nodules at about 700 million tonnes – roughly equal to current land-based reserves.

While the USGS has not published figures for copper resources in deep-ocean sulphides, others have put them at less than a 10th of the USGS forecast for manganese nodules – probably a very conservative estimate.

 

Exploration

Most of the contractors involved with the 27 active contracts are state-owned institutions, such as France’s Ifremer and BGR of Germany.

Private companies have also joined the hunt in recent years, including UK Seabed Minerals, Belgium’s G-Tec Sea Minerals and Keppel from Singapore.

All contractors must have official support from their own government, and 20 countries are currently backing exploration for these minerals. Five are developing countries – small island states in Asia and the Pacific.

The contracts run for 15 years, with the contractors originally expected to convert subsequently to a production phase. That has not happened.

Instead, all seven of the pioneer contracts have been given a five-year extension. At the same time, the ISA is working on regulations to govern extraction.

 

First

Production of minerals from international waters could begin during the next decade, with manganese nodules set to be the first target.

Long before then, however, Canada’s Nautilus company is likely to start output from the Solwara 1 sulphide ore field in 1 700 metres of water off Papua New Guinea’s continental shelf.

The mining equipment has already been designed and built, and a production ship will be ready in 2019. This activity could have great influence on the industry’s development elsewhere.

 

Present

Where the NCS is concerned, seabed minerals are known to be present in deep parts of the Norwegian Sea. The University of Bergen (UiB) found black smokers there more than a decade ago.

Drawing in part on the NPD’s large multibeam bathymetric data set, acquired for boundary mapping, the university has identified a number of sulphide deposits.

Including both smokers and gravel heaps, these are located along the volcanic Mohns Ridge between Jan Mayen and Bear Island and northwards on the Knipovich Ridge.

Samples have since been taken from a number of sulphide deposits and manganese crusts while mapping the Norwegian Sea in a long-running research partnership between the UiB and the NPD.

This is part of the university’s internationally acclaimed study of the volcanic processes leading to sulphide deposits, and of their unique fauna.

Where the NPD is concerned, the work is part of its general mapping of resources on the NCS – which forms one of its main duties.

The Norwegian University of Science and Technology (NTNU) has also recently begun work on seabed minerals, making its own investigations of the sulphide deposits identified by the UiB.

Norway’s continental shelf areas are expected to contain manganese crusts in parts of the deep Norwegian Sea and around the Yermak Plateau in the Arctic Ocean and Bouvet Island in the South Atlantic.

On the other hand, manganese nodules are not likely to exist in these waters, with the possible exception of the areas around Bouvet Island.

 

Chemical analyses of a number of metallic elements in manganese crust samples from the Norwegian Sea compared with average values in the north-western Pacific. The Norwegian Sea samples fall into two groups, as described in the article.

Chemical analyses of a number of metallic elements in manganese crust samples from the Norwegian Sea compared with average values in the north-western Pacific. The Norwegian Sea samples fall into two groups, as described in the article.

 

Commercial

The question now is whether these minerals are found somewhere on Norway’s continental shelves in such quantities and of such quality that mining them could be commercial. A lot more work and investigation is needed to provide a reliable answer.

To get the ball rolling, the NPD has carried out an initial series of chemical analyses of thick manganese crusts on steep slopes of the Jan Mayen Ridge and the Vøring Spur.

These have revealed interesting differences compared with such deposits in the rest of the Atlantic and in the Pacific.

Manganese crusts in the Norwegian Sea fall into two groups in terms of their lanthanide content. One has twice the amount found in Pacific and other Atlantic sources, the other has less.

Both categories contain substantially more lithium (20-80 times as much) and scandium (four-seven times). These are interesting “green” metals.

The group with a high lanthanide content also has a greater proportion of yttrium, and is therefore richer in the whole series of REEs.

These findings are extremely interesting. The question now is why these chemical characteristics have arisen and how this knowledge can be used for continued mapping of the quality and extent of the resources.

Similar studies are also needed for the sulphide deposits, which include testing methods for recording various types of data and sampling techniques.

 

Reliable

Only when good progress has been made here will it be possible to provide reliable estimates of the resources involved.

Good management also requires that such calculations come from responsible institutions committed to recognised standards for reporting resource figures. This is crucial for possible future decisions by both government and the private sector.

Although a number of results are available, little exploration for minerals has taken place on the NCS. Nor does current legislation take account of such activity.

The government is therefore drafting new and modern legal provisions governing mineral exploration on and exploitation of the NCS. These are currently the subject of a public consultation.

 

Value

The position today is roughly the same as when oil and gas exploration began on the NCS. What has made the petroleum industry a big success in Norway is that these resources have been converted into value for the whole society.

From the start, it has been clear that the state owns the petroleum resources and will manage them for the benefit of the entire population.

The country also had a shipbuilding industry and world-class maritime technology expertise. Combined with legislation and statutory regulations, this knowhow was crucial in managing the resources and the revenues they yielded.

Norway’s qualifications for repeating this success have not diminished, even if it now has fewer shipyards. Its expertise on maritime technology has developed further, and the country is a world leader for industry, research and education in this area.

In addition come 50 years of experience in all aspects of marine geological mapping and management of the continental shelf’s resources.

So Norway does not need to build up much in the way of additional structures to look after the possible new resources which might exist in the ocean depths.

The original Norwegian version of this article has previously appeared in the GEO geology journal.


Topics: Geology