Those are the things that provided the cover for why Howard Hughes built the Glomar Explorer which was supposed to mine them from the sea floor.
Former CIA Spy Ship Hughes Glomar Explorer Sold for Scrap
By: Sam LaGrone
September 9, 2015
https://news.usni.org/2015/09/09/former-cia-spy-ship-hughes-glomar-explorer-sold-for-scrap