Just as a reminder, the idea of mining deep sea manganese nodules was developed by Howard Hughes' Glomar subsidiary in the 1970s as a cover story for the CIA's Project AZORIAN, a project to build a "deep sea mining ship" (the Hughes Glomar Explorer) that would deploy a sub-surface barge (the HMB-1) with a giant grapple to raise the sunken Soviet nuclear missile submarine K-129.
As such the scheme had to be "sufficiently plausible bullshit" to withstand scrutiny, while not necessarily needing to be economically feasible.
As such the scheme had to be "sufficiently plausible bullshit" to withstand scrutiny, while not necessarily needing to be economically feasible.
(No, I'm not making this up.)
https://en.wikipedia.org/wiki/Project_Azorian