Method for recovering rare-earth mud, and recovery system

A method for recovering rare-earth mud comprising:

• (A) inserting a mud gathering pipe into a layer containing rare-earth mud under a seafloor;
• (B) preparing a slurry containing a rare earth by rotating a stirring device within the mud gathering pipe to loosen the rare-earth mud;
• and
• (C) transferring the slurry through a mud raising pipe,
• wherein the stirring device includes a drill pipe having a lower portion extending into the mud gathering pipe and an upper portion extending outside the mud gathering pipe,
• wherein the mud raising pipe extends around the upper portion of the drill pipe to form a double pipe structure,
• wherein the slurry is transferred by a circulating flow through an annulus part of the double pipe structure, that is formed between an outer surface of the drill pipe and an inner surface of the mud raising pipe, and
• wherein the method further comprises directing a fluid from inside the drill pipe into the annulus part via an opening of the drill pipe that faces the inner surface of the mud raising pipe, to generate the circulating flow.