Japan has the 8th largest Exclusive Economic Zone of . There are estimated large quantities of mineral resources such as methane clathrate, natural gas, metallic minerals and rare-earth mineral reserves stored in Japan's EEZ. Seabed mineral resources such as manganese nodules, cobalt-rich crust and submarine hydrothermal deposits are located at depths over . Most of these deep sea resources are unexplored at the seabed. Much of the seabed has a depth of to . Japan's mining law restricts offshore oil and gas production. There are technological hurdles to mine at such extreme depths and to limit the ecological impact. There are no successful commercial ventures that mine the deep sea yet. So currently there are few deep sea mining projects to retrieve minerals or deepwater drilling on the ocean floor.