About Manganese Nodules

Since the 19th century, we have been aware that the sea-bottom is littered with layers of metallic nodules, also known as manganese nodules, which are generally small but extremely metal-rich rocks containing large quantities of valuable manganese and smaller amounts of iron, copper, zinc, cobalt, and nickel. In the past fifty years there have been several efforts to devise means of “mining” the sea floor for manganese nodules, none of which have been technologically or economically practical. Concerns about the future of nodule extraction did, however, provide one of the major motivations behind the negotiations of the current International Law of the Sea.

– About Manganese Nodules –

The average manganese nodule is about the size of a potato, and forms as part of a very gradual multi-million-year process in which metals precipitate out of the ocean water or leave sea-floor hot springs and vents and form together into the nodules. They are dispersed throughout the sediment on the sea-bottom, both on the sea-floor itself as well as buried below it. The first were found in the relatively shallow Arctic Ocean during the 1800s, but science ships subsequently found them in all other oceans as well.

Because the sea-bottom in general is a relatively unexplored and poorly understood environment, the true nature and quantity of manganese nodules is difficult to estimate, although guesswork from the 1980s, during one of the peaks of interest in nodule mining, suggested that there probably hundreds of billions of nodules in total, with the largest number found on the abyssal plains (13-20,000 feet below the surface).

– Nodule Harvesting –

Because there are enormous quantities of manganese nodules, and because they contain a variety of economically very important metals (manganese itself, but also nickel, copper, cobalt, silicon, aluminum, and trace amounts of other valuable metals), there has been considerable interest in harvesting them from the ocean floor for refining. Hundreds of millions of dollars were invested by all advanced countries, including the U.S., Canada, Europe, and the Communist bloc, and in the 1970s one project did succeed in gathering a number of nodules in the eastern Pacific. However, as nickel prices fell and the true scope of the high-technology effort necessary for full exploitation became apparent, interest in manganese nodule development tailed off and has never recovered.

Despite this, the brief flurry of interest in what was heralded to be a bonanza in new resource extraction opportunities provided an important impetus to the negotiation of the UN Convention on the Law of the Sea in 1982. Under the Law of the Sea, an international organization called the International Seabed Authority was created and currently holds the authority to regulate manganese nodule mining projects, should they ever develop commercially. 

The history of manganese nodule mining, incidentally, does feature one interesting episode in the secret history of the Cold War. In 1974, as part of Project Azorian (sometimes known as Project Jennifer), the CIA developed a special sea-bed exploration ship called the Glomar Explorer specifically to recover the remains of a Soviet Golf II-class ballistic missile submarine which sank in the Pacific several years before. The billion-dollar project was one of the most expensive special operations of the entire Cold War, and was publicly explained as a manganese nodule mining test project.