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Critical Metals Recovery from Cook Islands
Polymetallic Nodules
Douglas Maxwell, Laurie Meyer, Colin Seaborn
Ocean Minerals LLC
ABSTRACT: Moana Minerals, under exploration license in te Cook Islands for polymetallic nodules, is
conducting a full range of project development feasibility assessments. The nodules contain cobalt, copper,
nickel, manganese and rare earth elements and represent a large source of these critical metals from a friendly
jurisdiction, with favorable economics and ESG when compared to traditional sources. Developing a processing
scheme for extracting the best mix of finished products is a key focus of Moana Minerals’ program. This paper
presents status of the Moana Minerals hydrometallurgical process development program, presenting results
from multiple bench scale testing activities as well as plans for next steps to perform scaled up locked cycle
testing in support of product sample assessments.
INTRODUCTION
In February of 2022, Moana Minerals (MM) was awarded
a polymetallic nodule exploration license by the Cook
Islands Seabed Minerals Authority (CI SBMA) for an area
of 23,630 km2 (just over 1%) of their EEZ. (Figure 1) The
license allows MM to explore for possible future harvest-
ing of seabed polymetallic nodules (aka “manganese nod-
ules” or “nodules”) for their strategic metal contents. As a
key part of a 5-year exploration program of work, Moana
Minerals has focused on development of a low temperature
and ambient pressure hydrometallurgical process called
Cuprion Sulfate. Nodules from the Cook Islands could be
available for commercial scale processing as early as 2028 in
time to help address projected Cobalt and Nickel metal
shortfalls at a significant scale.
Polymetallic Nodules
Polymetallic nodules are found in many abyssal areas (typi-
cally at depths of between 3000 and 6000m) of the world’s
oceans. They are concretions of predominantly iron and
manganese oxides and hydroxides. These concretions grow
around a “core” particle, that could be a fish tooth, a lump
of clay or a fragment of rock. The nodules are found sitting
on top of ocean bottom sediments, generally in a mono-
layer, and mostly uncovered. As concretions, the nodules
vary in size and shape however, metal grade continuity
seems to be a key feature at least for the nodules within the
Moana Minerals license area.
Besides iron and manganese, polymetallic nodules
contain numerous other metals of interest in varying con-
centrations. Nodules can contain potentially economically
significant amounts of commercially important metals such
as copper, nickel, cobalt, and rare earth elements (REEs).
These metals are typically distributed through the manga-
nese oxy-hydroxide matrix and the grain sizes generally are
too fine for the more valuable metals or their compounds
to be separated by mechanical mineral processing (grinding
and physical separation).
The best-known area of potentially commercially
exploitable polymetallic nodules is the Clarion-Clipperton
Zone (CCZ), an area in the eastern Pacific Ocean, north
of the equator, between Clarion Island and Clipperton
Critical Metals Recovery from Cook Islands
Polymetallic Nodules
Douglas Maxwell, Laurie Meyer, Colin Seaborn
Ocean Minerals LLC
ABSTRACT: Moana Minerals, under exploration license in te Cook Islands for polymetallic nodules, is
conducting a full range of project development feasibility assessments. The nodules contain cobalt, copper,
nickel, manganese and rare earth elements and represent a large source of these critical metals from a friendly
jurisdiction, with favorable economics and ESG when compared to traditional sources. Developing a processing
scheme for extracting the best mix of finished products is a key focus of Moana Minerals’ program. This paper
presents status of the Moana Minerals hydrometallurgical process development program, presenting results
from multiple bench scale testing activities as well as plans for next steps to perform scaled up locked cycle
testing in support of product sample assessments.
INTRODUCTION
In February of 2022, Moana Minerals (MM) was awarded
a polymetallic nodule exploration license by the Cook
Islands Seabed Minerals Authority (CI SBMA) for an area
of 23,630 km2 (just over 1%) of their EEZ. (Figure 1) The
license allows MM to explore for possible future harvest-
ing of seabed polymetallic nodules (aka “manganese nod-
ules” or “nodules”) for their strategic metal contents. As a
key part of a 5-year exploration program of work, Moana
Minerals has focused on development of a low temperature
and ambient pressure hydrometallurgical process called
Cuprion Sulfate. Nodules from the Cook Islands could be
available for commercial scale processing as early as 2028 in
time to help address projected Cobalt and Nickel metal
shortfalls at a significant scale.
Polymetallic Nodules
Polymetallic nodules are found in many abyssal areas (typi-
cally at depths of between 3000 and 6000m) of the world’s
oceans. They are concretions of predominantly iron and
manganese oxides and hydroxides. These concretions grow
around a “core” particle, that could be a fish tooth, a lump
of clay or a fragment of rock. The nodules are found sitting
on top of ocean bottom sediments, generally in a mono-
layer, and mostly uncovered. As concretions, the nodules
vary in size and shape however, metal grade continuity
seems to be a key feature at least for the nodules within the
Moana Minerals license area.
Besides iron and manganese, polymetallic nodules
contain numerous other metals of interest in varying con-
centrations. Nodules can contain potentially economically
significant amounts of commercially important metals such
as copper, nickel, cobalt, and rare earth elements (REEs).
These metals are typically distributed through the manga-
nese oxy-hydroxide matrix and the grain sizes generally are
too fine for the more valuable metals or their compounds
to be separated by mechanical mineral processing (grinding
and physical separation).
The best-known area of potentially commercially
exploitable polymetallic nodules is the Clarion-Clipperton
Zone (CCZ), an area in the eastern Pacific Ocean, north
of the equator, between Clarion Island and Clipperton