Exploring the Oceans

Deep sea mining is set to test the boundaries of technology, but it is certainly not a recent discovery, as the very first deep sea manganese nodules were discovered in 1872 – 1876 during a scientific voyage of the HMS Challenger. Only in recent years this industry has become increasingly economically feasible.

Deep sea mining, the process of retrieving minerals from sea or ocean floors, has a considerable historical background. Back in the 19th century vast areas of sea floor were discovered to be littered with manganese nodules, rock concretions consisting of concentrated layers of iron and manganese hydroxides. Towards the end of the 20th century the use of copper, nickel and other metals rose considerably, driving their prices up. This put focus on mining in deep waters and many studies were established to develop this industry. However, in the 1970s, large land mineral deposits were discovered, meaning prices decreased and the scientific trials done for deep sea mining offered little or no return on investment making deep sea mining economically unfeasible.

Why now?

Over the past decade the question of deep sea mining has arisen once more. Cees van Rhee, professor of dredging engineering at Technical University Delft comments: “The concentration of minerals found in deposits in deep sea is many times higher than land-based deposits.” This could mean mining in deep sea can be cheaper than land-based mining. Done well, the environmental impact could be lower in the water than on land. However, this is yet to be proven, as Marc Lavaleye, marine biologist at the NIOZ (Royal Netherlands Institute for Sea Research) states: “It doesn’t matter how
you approach deep sea mining, you will always have an impact on the environment and we must be wary of this.” In the ‘Ecology versus technology’ article we will pay more attention to the connection between deep sea mining and sea life.

Black smokers

And so the hunt for deep sea ore deposits has begun, driven by the western push for precious metals for the transition towards an electricity-based information and transportation infrastructure and the need for artificial fertilizers for the growing population. The industry name ‘deep sea mining’ can be deceiving, as Van Rhee points out: “Deep sea mining can start at 100 metres water depth, depending on where you find the deposits. Manganese nodules, however, can only be found at around four to six kilometres deep. Where you can find these, differs”, comments Van Rhee. “There are the SMS, seafloor massive sulfide, deposits, which exist much like submarine volcanoes and are also known as ‘black smokers’.” The hydrothermal vents exhale mineralising fluids into the ocean, containing, amongst others, copper, lead, zinc, gold and silver which precipitate upon the sea floor.

Heavy investments required

“When you look at conventional mining on land the percentage of minerals you can find is often less than one percent”, explains Van Rhee. “The percentage you find in minerals from the ocean floor is many times higher, which means this could be a very lucrative business. We should not forget, however, that this is a very costly undertaking requiring heavy investments.” The same opinion is shared by Olaf Waals, manager offshore at the MARIN (Maritime Research Institute Netherlands): “The Netherlands already has considerable knowledge regarding dredging and offshore technologies, which makes us a primary candidate to get involved in this industry. The technology used with the oil and gas industry will be heavily relied upon. This industry once moved from being land- based to now much further out at sea at many kilometres depth. Who is to say it cannot be done for mining as well? To tackle this deep sea mining industry correctly, we believe we must work together, like a joint venture. Many Dutch companies have ideas and also developments for deep sea mining, like IHC Merwede and Damen, and we can be there to advise and test. To be successful means cooperating. ”

Methods for mining

Once a site has been located for deep sea mining, a ROV (remotely operated vehicle) can collect samples, through which it can be established if the site is worth mining. A mining ship or station is then set up at the mining location. Jaap de Wilde, senior project manager offshore at MARIN, explains: “We really know of several methods of mining in deep waters, such as slurry transport. One method used a CLB, continuous- line bucket system, and a hydraulic suction system. The general idea is that this method is most practical for collecting manganese nodules. The method works as a type of conveyor belt in a direct line from ocean floor to ship. The nodules are transported to the ship, separated and the unnecessary elements are then returned to the ocean floor via another pipe.”

When looking at mining the minerals at black smoker sites another method has been developed, soon to be used by Nautilus, the first company to commercially extract minerals in Papua New Guinea. Here sea floor production tools mine the area, using cutters and a sub sea slurry pump that transports the goods to the production support vessel.

Explore or extract

Van Rhee: “Each method has its own challenges and each site will require different handling. Especially the seabed conditions are important. The SMS deposits can be considered as rock and the high hydrostatic pressure will make it even more difficult to excavate. The manganese nodules on the other hand are just situated on top of the seabed and can be collected more easily.”

Rules and regulations have been established by the United Nations Conventions on the Law of the Sea and came into effect in 1994. The International Seabed Authority (ISA) was established, their aim is to regulate deep sea mining ventures outside each country’s exclusive economic zone. The exclusive economic zone is a 200 nautical mile area in the surrounding coastal nations. The first signatures follow in 2001 and 2002, each for 15-year contracts. Eight organisations have applied and are authorized to explore for poly metallic (manganese) nodules. Marck Smit of the Netherlands Deep Sea Science & Technology Centre, comments: “The ISA so far only granted permissions for exploration, not for extraction. Nautilus will be extracting, but they are within the exclusive economic zone.”

The future

General opinion is that deep sea mining will definitely happen. The only question is how and when. The Dutch government has established nine top sectors of which ‘water’ is one. Within the top sectors businesses, scientists and ministries work together, and in the top sector ‘water’ special attention will be paid to developing means for deep sea mining which will further stimulate and enhance the Dutch competitiveness within the maritime industry.

Van Rhee: “There are promising developments, but I believe it will boil down to one issue: money. Who can afford the investments and will the outcome be sufficient to warrant the money spent?” De Wilde agrees, but also comments: “There are many unanswered questions and, truthfully, we know little about deep sea mining and more worryingly we know even less of the effectsontheenvironment.However,weshould take the opportunity to build this industry and protect the environment as much as possible. It really is exciting to stand on the threshold of such a development. Next to that, it is our belief that together with businesses, the government and scientific centers we will be able to create an innovative industry for the Netherlands.” It is obvious that a challenging and interesting time awaits those interested in deep sea mining.

Rebecca McFedries