REY-rich mud is a new type of deep-sea mineral resource concentrating rare-earth elements and yttrium (REY) that are indispensable for modern high-tech industries. It was discovered in the Pacific Ocean by Professor Yasuhiro Kato, the University of Tokyo, in 2011.
The REY-rich mud has multiple advantages including high REY concentrations, tremendous resource potential, ease of exploration, very low contents of harmful materials such as radioactive elements, and efficient extraction of REY, which makes the mud a highly promising resource for the industrially critical metals. In 2012, Professor Kato’s group confirmed the presence of REY-rich mud in the Japanese exclusive economic zone (EEZ) around Minami-Tori-Shima Island.
Moreover, within the Minami-Tori-Shima EEZ, they discovered the “extremely REY-rich mud” reaching 7,000 ppm of total REY concentration in 2013, which is the highest grade in the world ocean.
At present, collaborative works by the industries, academia and government toward the development of the mud are proceeding vigorously. These exhibition samples were taken from the deep-sea floor in the Minami-Tori-Shima EEZ.

REY-rich mud (Towards development of the frontier resources in deep-sea)
Size: 80×45×45, 100×60×60
Collection: Department of Systems Innovation, School of Engineering, The University of Tokyo
REY-rich mud is a novel deep-sea mineral resource concentrating rare-earth elements that are indispensable for various high-tech and green-tech products. The mud was discovered in the Pacific Ocean by Professor Yasuhiro Kato, The University of Tokyo, in July 2011. These exhibition samples were collected from the deep-sea floor in the Japanese exclusive economic zone around Minamitorishima Island.