Manganese nodules

The mineral
Polymetallic nodules, also called manganese nodules, are rock concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. The core may be microscopically small and is sometimes completely transformed into manganese minerals by crystallization. When visible to the naked eye, it can be a small test (shell) of a microfossil (radiolarian or foraminifer), a phosphatized shark tooth, basalt debris or even fragments of earlier nodules. As nodules can be found in vast quantities, and contain valuable metals, deposits were identified as having economic interest in the 1960s by John Mero.

Nodules vary in size from tiny particles visible only under a microscope to large pellets more than 20 centimetres (8 in) across. Most nodules (which are between 3 and 10 cm (1 and 4 in) in diameter) lie on the seabed sediment, often partly or completely buried.

Their surface textures vary from smooth to rough. They are frequently have botryoidal (mammilated or knobby) texture and vary from spherical to typically oblate, sometimes prolate, or otherwise irregular. The bottom, buried in sediment, is generally rougher than the top due to a different type of growth.

The average nodule has 24% manganese, iron (14%), copper (1%), nickel (1%), cobalt (0.25%) and traces of some other metals like platinum and titanium. The land based ores (manganite, purpurite, rhodonite, rhodochrosite, pyrolusite, mineraloids such as psilomelane and wad) contain 35% to 55% manganese. Those of greatest economic interest contain manganese (27-30%), nickel (1.25-1.5 %), copper (1-1.4 %) and cobalt (0.2-0.25 %). Other constituents include iron (6%), silicon (5%) and aluminium (3%), with lesser amounts of calcium, sodium, magnesium, potassium, titanium and barium, along with hydrogen and oxygen as well as water of crystallization and free water.

Formation
These nodules are thought to form when chemicals dissolved in seawater precipitate onto a small object on the sea bed. Leading theory state chemical reactions in seawater that are boosted by microbes, in a similar way as at underwater hot springs and the natural precipitation of excess metal from seawater. Manganese and iron from underwater volcanic eruptions can also contribute to nodule growth, as can the presence of algae and bacteria.

They grow at the extremely slow rate of just a few millimeters per million years, yet they have regularly seen growing in lakes, man-made reservoirs and on ship wrecks from both world wars.

In the 1890s
A few were found in Chile's Littoral waters and washed up on beaches.

In the 1940s
Japanese troops and fishermen encountered some in the TTPI.

In the 1950s
American troops and fishermen encountered some in the TTPI.

In the 1960s.
Serious test dredging and research was proposed by experts like John Mero.

In the 1970s
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GSF Explorer
GSF Explorer, formerly USNS Hughes Glomar Explorer (T-AG-193), was a deep-sea drillship platform initially built for the United States Central Intelligence Agency Special Activities Division secret operation Project Azorian to recover the sunken Soviet submarine K-129, lost during April 1968. It claimed to be mining Manganese nodules.

The cultural effect of Glomar Explorer is indicated by its reference to a number of books: The Ghost from the Grand Banks, a 1990 science fiction novel by Arthur C. Clarke; Shock Wave by Clive Cussler; Charles Stross's novel, The Jennifer Morgue; and The Hunt for Red October by Tom Clancy.

In the 1980s
Thedifficulty   of the    submarine in mining the ocean depths and the technological advances early 1980s in extracting ores on land had terminated interest on economic grounds by the late 1980s.

In the 1990s
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In the 2000s
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In the 2010s
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Occurrence
Most nodules (which are between 3 and 10 cm (1 and 4 in) in diameter) lie on the seabed sediment, often partly or completely buried. They vary greatly in abundance, in some cases touching one another and covering more than 70% of the sea floor. The total amount of polymetallic nodules on the sea floor was estimated at 500 billion tons by Alan A. Archer of the London Geological Museum in 1981.

Polymetalic nodules are found in both shallow (e.g. Baltic Sea) and deeper waters (e.g. central Pacific), even in lakes, and are thought to have been a feature of the seas and oceans at least since the deep oceans oxidised in the Ediacaran period over 540 million years ago.

Polymetallic nodules were discovered in 1868 in the Kara Sea, in the Arctic Ocean of Siberia. During the scientific expeditions of the HMS Challenger (1872–1876), they were found to occur in most oceans of the world.


 *  Their composition varies by location, and sizeable deposits been found in four areas: 
 * 1) Penrhyn Basin near within the Cook Islands.
 * 2) North central Pacific Ocean in a region called the Clarion Clipperton Zone (CCZ) roughly midway between Hawaii and Clipperton Islands.
 * 3) The largest of the deposits in terms of nodule abundance and metal concentration occur in the Clarion Clipperton Zone on vast abyssal plains in the deep ocean between 4,000 and 6,000 m (13,000 and 20,000 ft). The International Seabed Authority estimates that the total amount of nodules in the Clarion Clipperton Zone exceeds 21 Bt of nodules containing more than 270 Mt of nickel, 5.95 Bt of manganese, 234 Mt of copper and 46.6 Mt of cobalt. This manganese nodule belt within the Clarion-Clipperton Fracture Zone, northeast equatorial Pacific.
 * 4) Peru Basin in the southeast Pacific.
 * 5) Southern tropical Indian Ocean in a region termed the Indian Ocean Nodule Field (IONF) roughly 500 km SE of Diego Garcia Island.
 * 6) The Marshall Islands was found since the 1960s to have untapped phosphate deposits, marine products and deep seabed minerals like manganese nodules.
 * 7) Palau was found since the 1960s to have mostly untapped forests, minerals (especially gold), marine products, deep-seabed minerals minerals like manganese nodules.
 * 8) The Federated States of Micronesia was found since the 1960s to have mostly untapped forests, marine products, deep-seabed mineral minerals like manganese nodules.
 * 9) Wake Island was initially thought to have some, but this was later disproved as no more than the odd scattered individuals in the island's exclusive ecanomic zone (EEZ).

All of these deposits are mostly in international waters apart from the Penrhyn Basin, which lies within the exclusive economic zone of the Cook Islands.

The newly found mid-Atlantic nodules in tropical ocean depths between South America and Africa resided in depth of between 16,400 feet and 18,000 feet (5,000 and 5,500 meters).

Mining plans and methods
Researchers became interested in mining the minerals in the early 1970s, since the contained valuable metals such as nickel, copper and cobalt, but the of the difficulty submarine in mining the ocean depths and the technological advances early 1980s in extracting ores on land had terminated interest on economic grounds by the late 1980s.

The average nodule has 24% manganese, iron (14%), copper (1%), nickel (1%), cobalt (0.25%) and traces of some other metals like platinum and titanium. The land based ores (manganite, purpurite, rhodonite, rhodochrosite, pyrolusite, mineraloids such as psilomelane and wad) contain 35% to 55% manganese. Those of greatest economic interest contain manganese (27-30%), nickel (1.25-1.5 %), copper (1-1.4 %) and cobalt (0.2-0.25 %). Other constituents include iron (6%), silicon (5%) and aluminium (3%), with lesser amounts of calcium, sodium, magnesium, potassium, titanium and barium, along with hydrogen and oxygen as well as water of crystallization and free water.

Environmental issues
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Usage
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2015\2016 prices and abundance

 * Nickel (2015):
 * 1) Abundance earth’s crust: 84 parts per million by weight, 30 parts per million by moles
 * 2) Abundance solar system: 80 parts per million by weight, 2 parts per million by moles
 * 3) 2015 cost, pure: $7.7 per 100g
 * 4) 2015 cost, bulk: $1.9 per 100g


 * Copper (2015):
 * 1) Abundance earth’s crust: 60 parts per million by weight, 19 parts per million by moles
 * 2) Abundance solar system: 700 parts per billion by weight, 10 parts per billion by moles
 * 3) Cost, pure: $9.76 per 100g
 * 4) Cost, bulk: $0.66 per 100g


 * Uranium (2015):
 * 1) Abundance earth’s crust: 2.7 parts per million by weight, 0.25 parts per million by moles
 * 2) Abundance solar system: 1 part per billion by weight, 4 parts per trillion by moles
 * 3) 2015 cost, pure: $ N\A per 100g
 * 4) 2015 cost, bulk: $9 per 100g


 * Gold (2015):
 * 1) Abundance earth’s crust: 4 parts per billion by weight, 0.4 parts per billion by moles
 * 2) Abundance solar system: 1 part per billion by weight, 10 parts per trillion by moles
 * 3) 2015 cost, pure: $5,540 per 100g
 * 4) 2015 cost, bulk: $3,800 per 100g


 * Manganese (2016):
 * 1) Abundance earth’s crust: 0.1% by weight, 360 parts per million by moles
 * 2) Abundance solar system: 10 parts per million by weight, 0.2 parts per million by moles
 * 3) Cost, pure: $6.5 100g
 * 4) Cost, bulk: $0.28 per 100g


 * Iron (2016):
 * 1) Abundance earth’s crust: 5.6 % weight, 2.1 % by moles
 * 2) Abundance solar system: 1000 parts per million by weight, 30 parts per million by moles
 * 3) Cost, pure: $7.2 per 100g
 * 4) Cost, bulk: $0.02 per 100g


 * Titanium (2016):
 * 1) Abundance earth’s crust: 0.56% by weight, 0.25% by moles
 * 2) Abundance solar system: 4 parts per million by weight, 100 parts per billion by moles
 * 3) Cost, pure: $661 per 100g
 * 4) Cost, bulk: $ per 100g


 * Cobalt (2016):
 * 1) Abundance earth’s crust: 25 parts per million by weight, 8 parts per million by moles
 * 2) Abundance solar system: 4 parts per million by weight, 0.7 parts per million by moles
 * 3) Cost, pure: $21 per 100g
 * 4) Cost, bulk: $4.40 per 100g

World Manganese production
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Also see

 * 1) Mining
 * 2) Nickel
 * 3) Wake Atoll
 * 4) Useful metals
 * 5) Midway Island
 * 6) Johnston Atoll
 * 7) Energy and resources
 * 8) Minerals and fuel in central Africa
 * 9) Trust Territory of the Pacific Islands
 * 10) Mineral mining, smelting, processing and shipping videos!