Comments thru ISOPE

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    • #2506 Reply
      Jin Chung
      Guest

      A good presentation.
      Collectors
      Any comments on solid collection with tow sled system that ISA group prefers.
      How about mechanical collection
      How to reduce tiny particles (e.s. soil, clay?)

      DISQUS didn’t work.
      Jin S Chung

    • #2526 Reply
      Jingchao Hu
      Guest

      Dear Professor Chung,

      Thank you for your questions and we are honored to have your interest in our research point.

      For the mechanical collection, actually, we have not tested that method before. According to the results of sea test conducted by OMI, the conclusion that the hydraulic collection method has a higher nodule pick-up efficiency and better adaptability to variations of seabed than mechanical collection was proposed. In our future studies, a quantitative comparative study between the mechanical collection and hydraulic collection will be investigated. And then, we may give more opinions on this issue.

      For the question of how to reduce sediments during the nodule collection, we think understanding the mechanism of the hydraulic collection is a critical step. Because the local velocity distribution (or local pressure distribution) near the collector is the essential cause of the nodule pick-up efficiency and the sediment diffusion. We try to reveal the flow field characteristics of the nodule collection flow for different kinds of collectors, then to explain their performances on nodules collection and environmental disturbances. We are dedicated to design the new kind of nodule collector with the flow characteristics like this: the velocity is larger near the top part of nodules and smaller near the bottom. Such nodule collection flow is considered to be beneficial for achieving a larger lift force as well as smaller disturbance to the seabed. Follow-up studies considering the sediments are still needed for us to validate the design of nodule collector, the ratio in collection of nodules and sediments is a matter of great concern to us.

      We appreciate your constructive questions.

      Jingchao Hu

    • #2582 Reply
      Jin Chung
      Guest

      As I remember for past 30 years, including the U.S. Natl Research Council’s EEZ Committee, the ISA “baseline” is “tow sled” from its environment point of view. You can ask COMRA what is the current collector baseline of China? Different from the ISA’s tow sled?
      Who are following tow sled collector?

      Jin Chung

    • #2583 Reply
      Jin Chung
      Guest

      As I remember for past 30 years, including the U.S. Natl Research Council’s EEZ Committee, the ISA “baseline” is “tow sled” from its environment point of view. You can ask COMRA what is the current collector baseline of China? Different from the ISA’s tow sled?
      Who are following tow sled collector?

      Jin Chung

    • #2588 Reply
      Jingchao Hu
      Guest

      Dear Professor Chung,

      Thank you for your kind suggestion. According to our investigation, we are told that there is no definite baseline for nodule collector by now. However, experts of COMRA do suggest that we must reduce the disturbance of mining activity as much as we can with the help of current technology. From the perspective of ecological preservation, the baseline is that no ocean species should be seriously reduced during the process of mining.

      For the second question, we are sorry that we are not sure about the answer.

      Jingchao Hu

    • #2589 Reply
      Jin Chung
      Guest

      In case ISA continue to support “tow sled” ISA’s baseline, why should invest so much in mechanical and hydraulic system?
      Jin Chung

    • #2591 Reply
      Jingchao Hu
      Guest

      Dear Professor Chung,

      Thank you for your question.
      According to our investigation, we have found many papers arguing that deep-sea mining would bring serious disturbance to the environment around the seabed. And it is investigated that impact of improper mining method remains for decades after the mining activity. We believe that studying environment-friendly collection method would dispel environmental groups’ doubt and worry on deep-sea mining. To search for a better nodules extraction method which minimizes the disturbance, we study the mechanical and hydraulic collection.

      Jingchao Hu

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