Seabed mining utilizing circulating current based on water level differences

Apparatus for sucking and extracting seabed mineral resources utilizing a circulating current based on the difference of water levels comprising:

• a working ship traveling on an ocean and mounted at its upper portion with an external cistern containing seawater at a level higher than the level of seawater on the ocean;
• a hollow box shaped tank having its bottom opened, sunk liftably into the sea bottom by a rope from said working ship, and having a rotatory driving mechanism for causing said tank to be trawled along the sea bottom while stirring it when said working ship travels on the ocean;
• an elongated flexible coaxial pipe with both ends opened which includes an inner pipe and an outer pipe arranged coaxially with the inner pipe, the upper portion of which is disposed within the external cistern of said working ship, and which has an enlarged hopper mouth at its lower end disposed within said tank through the upper wall thereof;
• a suction pump joined within the external cistern to the upper end of said coaxial inner pipe for sucking mineral resources and seawater from within said tank;
• selection means for selecting seabed mineral resources out of seawater sucked up by said pump from said tank through said coaxial inner pipe into the external cistern and gathering the selected mineral resources in said working ship;
• and
• returning means for bringing the seawater after selecting out the seabed mineral resources by said selection means back into said tank through a space defined by an outer wall of said coaxial inner pipe and an inner wall of said coaxial outer pipe utilizing the difference between the level of seawater contained in the external cistern and the level of seawater on the ocean.