Unknown
International Society of Offshore and Polar Engineers
In:
In: Proceedings of the Third (1999) Ocean Mining Symposium, Goa, India, November 8-10, 1999. International Society of Offshore and Polar Engineers, pp. 97-104. ISBN 1-880653-45-1
Publication Date:
2017-01-24
Description:
Deep ocean floor is the storehouse of
vast quantities, of mineral resources and
manganese nodules are one of the
important resources. As these deposits lie
at depths greater than 5000 m, sampling the
nodules and accurate resource evaluation is
expensive and time consuming. Traditional
methods of nodule sampling are the free fall
grabs and tethered samplers like Vanveen
grabs, corers etc. and the remote sensing
methods commonly used are deep towed
photography and videos. The use of high
frequency acoustics for nodule abundance
estimation was attempted in the past with
partial success. This technique is not
conclusive. We present here, method of
semi quantitative evaluation of nodule
resource estimation using the rms (root
mean square) backscatter amplitude gain
values from a multibeam echosounding
system. Normally, the echosounding
systems provide information only about the
water depths whereas the sidescan images can provide informatian on the targe and
smatt scale roughness and seafloor
composition in terms of texture etc. Present
day multibeam sonars can produce sidescan
images of the surveyed region. The
multibeam system- Hydrosweep on Indian
Research ship ORV Sagar Kanya doesn't
provide the sidescan images but, only gives
the rms amplitude values for each of the 59
pre formed beams. Here in this report the
rms amplitude values are utilised to generate
pseudo sidescan images of the seafloor.
Type:
Book chapter
,
NonPeerReviewed
Format:
text
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