COBALT-RICH FERROMANGANESE CRUSTS
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Exploration
4.1
Exploration involves the identification, delineation and eval-
uation of deep sea mineral resources and generally requires
sophisticated, multipurpose research vessels using advanced
technologies such as deep sea mapping equipment, remotely
operated vehicles, photographic and video systems, and sam-
pling and drilling devices (Figure 14).
Exploration for ferromanganese crusts typically involves the fol-
lowing steps:
• bathymetric mapping of seamounts using acoustic survey-
ing (for example, wide-swath Multi-Beam Echo Sounder sys-
tems) and analysis of bathymetric data (Figure 15);
• determining distribution of hard-rock outcrops and sediment-
covered areas of seamounts using back-scatter images from
side-scan sonar systems. These images can be ground-truthed
using camera/video tows. Small-scale features can be imaged
using an Autonomous Underwater Vehicle (AUV) equipped
with bathymetry, side-scan, and photo/video capabilities;
• ferromanganese crust sampling to determine metal grade
and crust thickness. Once sampling sites are identified,
dredge hauls, TV grab samplers, and core samplers can ob-
tain samples using winches on the ship. More detailed and
precise sampling can be carried out using a remote operated
vehicle (ROV).
Figure 14. Exploration tools.
Finder-installed
deep sea camera
Free fall grab
Multi beam
eco sounder
Dredge
bucket
ROV
(Remotedly
operated
vehicle)
GPS
Sources: adapted from Japan Oil, Gas and Metals National Corporation.
