A black smoker, surrounded by it's unique eco-system, spews rich mineral sulphides from the sea bottom at a depth of several kilometers - U of Washington

While finding rich mineral deposits in Papua New Guinea is nothing new, the Nautilus discovery and their proposal to begin mining within two years is groundbreaking - in this case sea-bottom breaking - and has raised environmental concerns from scientists. Some of them believe the origin of all life on Earth may be in danger because the mining will target the huge, mineral-rich deposits around   ‘black smokers’ or the sea-bottom volcanic geysers which support the world rarest eco-systems and may hold secrets to scientific advancement in pharmaceuticals and biotechnical applications.

But the deposits are valuable and hard to ignore while the potential values of chemosynthic sea life has yet to be found.   Sulfides from the Conical Seamount off Papua New Guinea (2.8 km basal diameter at 1,600 m water depth) have been found to contain an average gold content of 26 ppm, with a maximum content in excess of 230 ppm, about 10 times the average value of mineable gold deposits on land.

David Hayden, the CEO of Nautilus, says mining the sea bottom will be as revolutionary as the development of off-shore oil rigs was in the 1950’s. He contends deep sea mining will help to meet the growing global hunger for minerals, especially the increasing demand from fast-developing India and China.  

Nautilus began prospecting in 2006 after entering into a collaborative agreement with the Woods Hole Oceanographic Institution to undertake joint exploration and scientific research. The deposits Nautilus has been exploring off the shores of Papua New Guinea are in the relatively shallow waters of the Bismarck Sea from 200 to 2,000 meters below the surface.  Nautilus says it can extracts from the ocean floor through the use of new, undersea mining technology.   The company has contracted with an American shipbuilder for a 120 million-dollar custom-made vessel to serve as the floating command center for submerged remote-controlled mining machines. They hope to begin operations in 2009.
   

The super-heated water of a black smoker emerges from sea bottom vents under hundred of atmospheres of pressure. Unable to boil, it can reach temperatures as high as 400 C. Heavy metal sulphides absorbed by the superheated water precipitate out as water rises and cools, creating the surrounding deposit of metallic sulphides, estimated to be as large as 100 million tons at a single site - Northwestern University

The world’s first attempt at undersea mining began in the late 1950's when  American Sam Collins established Tidal Diamonds to mine at sea off the Skeleton Coast of Namibia and found diamonds were more abundant on the sea bed than on land.  He  mined the ocean floor for nine years and extracted 1.5 million carats of diamonds, but the  company was literally unable to stay afloat and was bought by the De Beers diamond group in the late 1960’s.

In the late 1970’s, scientists discovered mineral-rich manganese nodules on the sea bottom of the Atlantic near submerged volcanic domes and chimney-like vents they called ‘black smokers’ because of the plume of back, mineral-rich water spewing like smoke from the chimneys. While mining the manganese nodules proved to difficult and expensive for the technology of the times, studies showed the super-heated water emerging from the vents also cooled to form sulfide deposits thought to be rich in gold, copper and base metals at depths o more than 5,000 meters, also  out of reach of contemporary mining at the time.

In a 1994 treaty, International Seabed Authority (ISA) took responsibility for ensuring that the benefits of mining in international waters beyond the continental shelf are equitably shared, with emphasis on ensuring a fair payment to developing countries and protection of the environment from harmful effects. But they have no authority when it comes to the territorial waters within national boundaries, where  local governments have the final say.

 

Giant sea worms and huge clams thrive near the vents, the only fully chemosynthetic life forms on the planet. The could be the source of yet undiscovered pharmaceutical and biotechnical applications - U of New Hampshire

 

While mining the active   volcanic vents would be too difficult, Nautilus plans to mine up to within 500 meters of active vents using remotely-operated underwater cutters and a hydraulic pump system. While the technical details remain to be defined, most estimates are it will be similar to terrestrial strip-mining, removing deposits within the top 20 meters of the seafloor with an estimate of roughly two million tons of ore per year being pumped to the surface.

In an article in Science Daily, Marine Geologist Jochen Halfar of the University of   Stuttgart points out that the environmental consequences of sea bed mining are generally unknown and theorises they could be severe.

Halfar believes the process will increase the amount of fine sediment in the surrounding sea water thus altering the natural habitat and endangering the sensitive chemosynthetic life forms.   He’s also worried that the nutrient-rich, warm  water from near the vents could cause ecological changes in sea life when it is pumped to the surface, warming the much cooler upper levels and  causing algal blooms and threatening commercial fishing.  

There is also concern the contaminants could drift beyond territorial waters, damaging eco-systems and the food-chain within the economic zones of other nations, and while any country nation has the right to exploit it’s own resources, under international law it cannot damage the environment beyond its own borders.

Papua New Guinea is only one area   where Nautilus has staked it’s claim.   They’re also licensed to prospect in the national waters of Tonga, Fiji and the Solomon islands, Pacific island nations where minerals are in short supply and off shore mining might be seen as a needed boost for local economies in the future. The question remains to be answered at what cost, economically and environmentally,  will they be mined?