16
Y. Fouquet and D. Lacroix
Stakeholder Involvement
Stakeholder involvement concerns areas mainly located in EEZs with scientific investment by the following countries: Japan, United States, Korea, France, China,
Brazil (international waters). There is no industry and are few publications. The current legal framework is on a national scale. For international waters, this framework
is currently being defined by ISA.
Nodules: Relative Certainties and Uncertainties
Polymetallic nodules are known in all the oceans, at all latitudes, at depths of over
4,000 m and in areas characterised by a low sedimentation rate and radiolarian ooze.
In particular, these areas allow carbonates to dissolve, due to greater acidity of deep
waters, caused by greater solubility of CO 2 with pressure.
Metal abundance and wealth on the seabed vary greatly. From 1973, fields with
a high density of nodules were found along an east-west belt in the North Pacific
(Clarion-Clipperton Zone). Nodules form dark-coloured balls, 5–10 cm in diameter,
containing around 40 % water. They are mainly composed of manganese and iron
hydroxides. The most crystallised layers are the richest in nickel and copper, which
do not form specific minerals, but are incorporated in the crystalline networks of
manganese and iron oxides.
The base metals contained in nodules are iron (7–23 %), manganese (7–26 %),
copper (290–10,200 ppm), nickel (2,600–12,800 ppm) and cobalt (2,400–
8,000 ppm). The Clarion-Clipperton Zone presents high concentrations of copper
(0.82 %), nickel (1.28 %) and manganese (25.40 %), and many mining licenses have
been allocated for this area. These are the metals that have been considered in economic estimations. Copper is found in concentrations on average double those of
the major mines in the Andes (0.5 %). Nodules can have high levels of rare elements
such as cerium (0.1 %). Other elements such as molybdenum, tellurium, vanadium,
zirconium and thallium can be found at concentrations of several 100 gm/t.
Nodules can also be considered as strategic reserves for base metals and for
certain rare metals. Several countries, including the United States and Germany,
have undertaken to resume analyses of their collections of nodules using modern
analytical methods in order to determine the variability in the composition of minor
elements and in particular rare earths.
Recent estimations for the Clarion-Clipperton Zone show that, for a surface area
of around 9 million km
2
(i.e. 15 % of the Pacific floor at a depth of between 4,000
and 5,000 m), the weight of nodules is 34 times 10
9
t, i.e. 7.5 billion t of manganese,
340 million t of nickel, 275 million t of copper and 78 million t of cobalt. Nodules
also contain certain trace metals, which are currently generating growing interest.
Their mining potential has been highlighted since the 1950s due to nickel contents greater than or equal to those of laterite deposits, copper contents greater than
or equal to those of major land-based porphyry copper deposits (0.5 % copper) and
cobalt contents similar to those of land-based deposits. The “metal content” value
Y. Fouquet and D. Lacroix
Stakeholder Involvement
Stakeholder involvement concerns areas mainly located in EEZs with scientific investment by the following countries: Japan, United States, Korea, France, China,
Brazil (international waters). There is no industry and are few publications. The current legal framework is on a national scale. For international waters, this framework
is currently being defined by ISA.
Nodules: Relative Certainties and Uncertainties
Polymetallic nodules are known in all the oceans, at all latitudes, at depths of over
4,000 m and in areas characterised by a low sedimentation rate and radiolarian ooze.
In particular, these areas allow carbonates to dissolve, due to greater acidity of deep
waters, caused by greater solubility of CO 2 with pressure.
Metal abundance and wealth on the seabed vary greatly. From 1973, fields with
a high density of nodules were found along an east-west belt in the North Pacific
(Clarion-Clipperton Zone). Nodules form dark-coloured balls, 5–10 cm in diameter,
containing around 40 % water. They are mainly composed of manganese and iron
hydroxides. The most crystallised layers are the richest in nickel and copper, which
do not form specific minerals, but are incorporated in the crystalline networks of
manganese and iron oxides.
The base metals contained in nodules are iron (7–23 %), manganese (7–26 %),
copper (290–10,200 ppm), nickel (2,600–12,800 ppm) and cobalt (2,400–
8,000 ppm). The Clarion-Clipperton Zone presents high concentrations of copper
(0.82 %), nickel (1.28 %) and manganese (25.40 %), and many mining licenses have
been allocated for this area. These are the metals that have been considered in economic estimations. Copper is found in concentrations on average double those of
the major mines in the Andes (0.5 %). Nodules can have high levels of rare elements
such as cerium (0.1 %). Other elements such as molybdenum, tellurium, vanadium,
zirconium and thallium can be found at concentrations of several 100 gm/t.
Nodules can also be considered as strategic reserves for base metals and for
certain rare metals. Several countries, including the United States and Germany,
have undertaken to resume analyses of their collections of nodules using modern
analytical methods in order to determine the variability in the composition of minor
elements and in particular rare earths.
Recent estimations for the Clarion-Clipperton Zone show that, for a surface area
of around 9 million km
2
(i.e. 15 % of the Pacific floor at a depth of between 4,000
and 5,000 m), the weight of nodules is 34 times 10
9
t, i.e. 7.5 billion t of manganese,
340 million t of nickel, 275 million t of copper and 78 million t of cobalt. Nodules
also contain certain trace metals, which are currently generating growing interest.
Their mining potential has been highlighted since the 1950s due to nickel contents greater than or equal to those of laterite deposits, copper contents greater than
or equal to those of major land-based porphyry copper deposits (0.5 % copper) and
cobalt contents similar to those of land-based deposits. The “metal content” value