There has been much talk over the years about the scarcity of certain metals, of the gradual exhaustion of reserves at grades that are economical to extract and the dangers this poses for the well being of the global economy. But a group meeting in Massachusetts this past week are seeking to better understand the opportunities that previously unexploited but massive reserves of minerals under our oceans could offer a world rapidly consuming the available land based deposits. The Woods Hole Oceanographic Institution (WHOI) will host an international gathering of scientists, policymakers, environmentalists and industry representatives to discuss mining precious metals from the seafloor.
Recent seafloor mining proposals are centering on massive sulphide deposits-containing copper, gold, silver and zinc-that are found in deep-sea hydrothermal vent systems. These systems are formed in places of volcanic activity where hydrothermal fluid carries with it dissolved metals and other chemicals from deep beneath the ocean floor. It sounds like the stuff of science fiction but combining land based technologies with skills developed in the off shore oil exploration industries, Nautilus Mining, a company backed by Anglo American and Teck Cominco is investing hundreds of millions in an operation off the coast of Papua New Guinea. The company expects to lift 6000 tons of ocean floor material about a mile to the surface for treatment each day. Nautilus is looking at a possible $1bn return on its investment saying the amount of copper in a ton of land mined material last year was 0.8% copper, but samples taken from drillings near these vents have yielded 8.3 to 11.1% copper and 6.5 to 8 g/ton of gold. Other sites have shown concentrations of zinc at 22.7% and silver at 77g/ton in addition to copper and gold. For the time being, though even these levels of metallic concentration are not enough, the project has been put onto a slow track while the copper price remains relatively low.
The challenges appear to be two fold. First, they are technical. The depths can be up to 2 kms or over a mile deep. Pressures are immense and mining equipment is being designed and engineered from scratch to operate at these depths. The second is environmental. The life forms existing around these hydrothermal vents are unique and wholesale mining would be sure to destroy these delicate ecosystems with potentially unknown consequences. Mining companies argue that the effects would be localized. That unlike land based operations, they don’t have to build roads, power lines and so on but they also admit that destruction of the hydro thermal vents and the ecosystem on which the unique organisms around them depend would be inevitable. It could be many years before the vents would return to pre-mining conditions. Although opinions vary widely about the desirability of exploiting these reserves ” some arguing that ocean floor mining is actually less environmentally damaging than surface mining – there is bound to be extensive objections on environmental grounds from some quarters.
Where do you stand on these issues? Should mining licenses be granted for resource extraction from the ocean floor? What happens when mining companies locate reserves that are outside territorial waters boundaries, who decides then?