Resource Assessment of Polymetallic Nodules Using Acoustic Backscatter Intensity Data from the Korean Exploration Area, Northeastern Equatorial Pacific SCIE SCOPUS KCI

Cited 5 time in WEB OF SCIENCE Cited 5 time in Scopus
Title
Resource Assessment of Polymetallic Nodules Using Acoustic Backscatter Intensity Data from the Korean Exploration Area, Northeastern Equatorial Pacific
Author(s)
Yoo, Chan Min; Joo, Jongmin; Lee, Sang Hoon; Ko, Youngtak; Chi, Sang-Bum; Kim, Hyung Jeek; Seo, Inah; Hyeong, Kiseong
KIOST Author(s)
Yoo, Chan Min(유찬민)Lee, Sang Hoon(이상훈)Ko, Youngtak(고영탁)Chi, Sang Bum(지상범)Kim, Hyung Jeek(김형직)Hyeong, Kiseong(형기성)
Publication Year
2018-06
Abstract
A high level of confidence in resource data is a key prerequisite for conducting a reliable economic feasibility study in deep water seafloor mining. However, the acquisition of accurate resource data is difficult when employing traditional point-sampling methods to assess the resource potential of polymetallic nodules, given the vast size of the survey area and high spatial variability in nodule distribution. In this study, we analyzed high-resolution acoustic backscatter intensity images to estimate nodule abundance and increase confidence levels in nodule abundance data. We operated a 120 kHz deep-towed sidescan sonar (DSL-120) system (1x1 m resolution) across a 75 km(2) representative area in the Korean Exploration Area for polymetallic nodules in the Northeastern Equatorial Pacific. A deep-towed camera system was also run along two tracks in the same area to estimate the abundance of polymetallic nodules on the seafloor. Backscatter data were classified into four facies based on intensity. The facies with the weakest and strongest backscatter intensities occurred in areas of high slope gradient and basement outcrops, respectively. The backscatter intensities of the two other facies correlated well with the nodule abundances estimated from still-camera images. A linear fit between backscatter intensity and mean nodule abundance for 10 zones in the study area yielded an excellent correlation (r(2) = 0.97). This allowed us to compile a map of polymetallic nodule abundance that shows greater resolution than a map derived from the extrapolation of point-sampling data. Our preliminary analyses indicate that it is possible to greatly increase the confidence level of nodule resource data if the relationship between backscatter intensity and nodule abundance is reliably established. This approach has another key advantage over point sampling and image analyses in that detailed maps of mining obstacles along the seafloor are produced when acquiring data on the abundance of polymetallic nodules. The key limitation of this work is a poor correlation between nodule coverage, as observed from photographs, and nodule abundance. Significant additional ground truth sampling using well located box cores should be completed to determine whether or not there is a real correlation between the backscatter and abundance.
ISSN
1738-5261
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/887
DOI
10.1007/s12601-018-0028-9
Bibliographic Citation
OCEAN SCIENCE JOURNAL, v.53, no.2, pp.381 - 394, 2018
Publisher
KOREA OCEAN RESEARCH DEVELOPMENT INST
Subject
ECHO CHARACTER; SEA; SEDIMENTATION
Keywords
polymetallic nodule; nodule abundance; deep-towed sidescan sonar; backscatter intensity; Clarion-Clipperton Zone
Type
Article
Language
English
Document Type
Article
Publisher
KOREA OCEAN RESEARCH DEVELOPMENT INST
Related Researcher
Research Interests

deep sea mineral resources,deep sea sediments,심해저 광물자원,심해저 퇴적물,심해 환경

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