MANGANESE NODULES
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4.1.1 Acoustic Survey
The first phase of manganese-nodule acoustic surveying involves
large-scale reconnaissance grid surveys with spacing of several
tens of square kilometres. This is carried out using wide-swathmul-
tibeam echo sounder systems to produce bathymetric maps of the
region, whichpermit elimination of those areasnot suited tomining
(such as seamounts, troughs, cliffs, steep or rugged terrain, etc.).
The second phase of acoustic surveying involves more de-
tailed imagery within a prospective area, with the aim of pro-
ducing a complete bathymetric map and a map of estimated
nodule abundance. This typically involves using deep-towed
sidescan sonar to generate high-resolution sea-floor images
of the flat areas that are more favourable for mining. The deep-
towed systems are also able to detect small-scale features
and variations in nodule abundance.
Bathymetric map of pilot area
showing the selected point
about Mn’s abundance. Photo
courtesy of KIOST.
