Issue link: https://viewer.e-digitaleditions.com/i/131975
miningreview deposits within the continental shelf and the 200-nautical-mile economic exclusion zone. On the bottom of the ocean around us there are all sorts of interesting finds, including: heavy mineral sands that contain zircon, rutile and ilmenite; alluvium containing diamonds, topaz, tin and gold; nodules and crusts of manganese; and bedrock deposits of bauxite (the principal ore used to make aluminium), coal, iron, tungsten and manganese. Some of these deposits have already been mined, if you can call it that. Sand for construction has been dredged in Moreton Bay, off the coast from Brisbane, and lime sand has been dredged off the coast from Fremantle to manufacture cement. The easiest pickings nearby would be deep-sea ferromanganese nodules (which are common to the south and west of Australia) and crusts containing copper, nickel, cobalt and manganese (which have been spotted under water to the south and west of Tasmania). A deposit of alluvial tin measuring about 200 million cubic metres has been identified in Ringarooma Bay in Tasmania, and Manganese nodules have been found in the Tasman Sea. About 900,000 square kilometres of closely packed nodules are sitting under the sea in the Cape Leeuwin region of south-west Australia, but the water there varies between 4,300 metres and 5,300 metres deep, so it's not just a case of shovelling them up – until someone designs a robot to do the job. Countdown to asteroid mining Fast Fact About 90 billion tonnes of rare-earth minerals lie beneath the Pacific Ocean, say scientists from The University of Tokyo. That's almost a thousand times the estimate of the minerals onshore. If accessing minerals from the sea bed significantly increases available resources, excavating minerals from asteroids would yield an infinite supply – in theory. US-based company Planetary Resources thinks it's on the way to mining extraterrestrial matter by focusing on the 1,500 asteroids that are close enough to earth to make the venture worthwhile. The company is working on a process where it sizes up asteroids using its Leo Space Telescope and then sends "interceptors" and "rendezvous prospectors" to get to work on these flying rocks. While it's early days and there's nothing in orbit yet, Planetary Resources has attracted backing from two Google executives and filmmaker James Cameron. Planetary Resources president Chris Lewicki has committed to mining missions as early as the next decade. Lewicki is looking for iron, nickel and platinum-group metals, but an initial focus will be water. "Water's elements, hydrogen and oxygen, can be used to formulate rocket fuel," the company claims. "Using the resources of space – to explore space – will enable largescale exploration of the solar system." Planetary Resources is not alone. There's competition in space, with USbased Deep Space Industries planning to launch missions to asteroids by 2015. It will also aim to turn water into rocket fuel so exploration can be based in space and the cost of sending things from earth kept down. "With the effects of gravity at a minimum, we can do amazing things regarding moving, construction and innovations in chemistry and physics," the company says.