Significant seafloor massive sulphides, including copper, zinc, and silver, gold and so on, are distributed in the EEZ of Japan, including substantial deposits in the Okinawa Trough and Izu-Bonin back-arc basin. In 2008, the Japan Oil, Gas and Metals National Corporation (JOGMEC), commissioned by the Ministry of Economy, Trade and Industry (METI), began exploration survey and technological development program for the development of the seafloor massive sulphides (SMS). Since then, JOGMEC conducted significant testing for excavation and lifting for SMS. In August-September 2017, actual SMS ore was continuously lifted from a depth of 1,600m to lifting support vessel, as part of mining test.
In Japan, the Basic Act on Ocean Policy provides a basic outline of matters regarding the ocean and was promulgated in July 2007. Following the Act, in March 2008, the Cabinet introduced the "Basic Plan on Ocean Policy", to promote measures concerning the ocean specifically and overall. In particular this legislation defines clearly the plan for the commercialization of SMS that have not yet been commercialized (Cabinet Office, 2008 and 2013).
METI introduced its "Plan for the Development of Marine Energy and Mineral Resources" as roadmap for commercializing SMS and other marine mineral resources based on the Basic Plan for Ocean Policy in 2008 and 2013 respectively, and in 2013 METI decided to conduct pilot test for excavation and ore-lifting test using actual SMS ore in FY2017. This test was introduced in this Development Plan; offshore pilot test: integrated excavation and lifting system (water depth of 700–1,600m, 2–4 weeks ship time, 2017–2018) (METI, 2013).
The history of development of marine mineral resources is extremely old. In the 1970s, large-scale mining tests for polymetallic nodules (manganese nodules) were conducted by some international consortiums in the Clarion-Clipperton fracture zone (CCZ) of the northeastern Pacific Ocean, beyond the national jurisdiction. Manganese nodules are distributed in the form of semi-submerged in pelagic sediments of the seabed at a depth of about 4,000–5,000 m.
