Technology to mine deep seabed similar enough to offshore oil development to not present technical barrier

One reason massive-sulphide formations beguile miners is that the metals they contain—notably copper, gold, zinc and silver—are highly concentrated. Another is that they are often big, 200 metres wide and long, tens of metres thick, and may contain several million tonnes of ore. All lie on the surface of the seabed, and many are only 1-2km below water level. At that depth technology developed for the offshore oil industry can nowadays be employed for mining. In particular, the deep-water pumps and suction pipes developed to bring subsea oil up to the surface can be used in the riser pipes needed to bring minerals (mixed with water) up from a massive-sulphide mine. The oil industry has also developed remotely-operated vehicles to make trenches for seabed pipelines, which can be adapted for cutting ore, even though it may lie much deeper, at, say, 1.5km down. In general the technology in the machines needed to carry out deep-water mining is no longer exotic. Woods Hole Oceanographic Institution has a vehicle that can reach depths of 11km.