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miningreview It therefore takes less ore to produce the same quantity of mineral, Williams says, if miners can figure out a cheap and clean way to bring it to the surface. Another Canadian miner looking offshore is DeepGreen Resources, which plans to reach 4,000 metres down into the water between Hawaii and Mexico to pick up tennis-ball-sized nodules containing metals. The company expects the nodules to be about one-third manganese, a metal used in steelmaking, and to contain cobalt, nickel and copper. DeepGreen Resources hopes to begin mining by 2020. Nodules are formed from minerals dissolved in sea water, and mining them sounds as easy as picking up apples from the grass in an orchard. DeepGreen Resources says there could be 500 million tonnes of these nodules within the parameters of its survey title. The geology way down below is defined more by the action of plate tectonics than high pressure, Williams says. "Vent systems are formed predominantly around sea floor spreading centres where continental plates are moving apart," he explains. "Water flows down through cracks in the earth's mantle, where it is geothermally heated. It is then emitted through the vents, forming chimneys on the sea floor. These are typically rich in dissolved minerals." Some minerals are transported to the surface when they dissolve in superheated water and are eventually deposited on the sea floor. Miners will have to tread carefully around these vents, as the elevated temperatures and higher concentrations of minerals and gases support a variety of life forms not found anywhere else on the planet, says Williams, whose marine robotics research sees him work closely with marine ecologists, geologists and archaeologists. "Much of this life depends on chemosynthetic bacteria, which feed on hydrogen sulfide. This supports a local ecosystem that includes invertebrates, such as copepods and amphipods, and larger organisms such as tube worms, snails, shrimps and eels." Diamond Fields International, another Canadian company, plans to use a floating platform fitted with a vacuum hose to suck up silt 2,000 metres below the surface of the Red Sea, about 115 kilometres west of Jeddah, Saudi Arabia. Copper, silver, zinc and traces of gold are the quarry the company hopes to start harvesting by next year. Core samples taken in the 1960s extended about eight metres into the seabed, but new seismic data indicates that sediments may be up to 160 metres thick. "The composition of these deeper sediments is currently unknown, but they offer the potential to host a further significant resource," states Diamond Fields International on its website. Resources exploration on the ocean floor is nothing new. The United Nations established the International Seabed Authority in 1994 to oversee mining in international waters. Exploration activity has picked up over the past couple of years, with the authority signing four new contracts with groups from Japan, Korea, Russia and China. In Australia, the Northern Territory Geological Survey imposed a moratorium on new applications for seabed mining following a spike in interest. Commonwealth agency Geoscience Australia has mapped offshore mineral "DeepGreen plans to reach 4,000 metres down into the water … to pick up tennisball-sized nodules containing metals." 63