Hayden says it’ll help meet hunger for minerals

Peter May
On June 20, 2007, Canadian-based Nautilus Minerals Inc. announced the discovery of high-grade deposits of gold, copper and zinc mineralisation on the ocean bottom near its Solwara 5, 6 & 7 sites in the Bismarck Sea, off Papua New Guinea, a part of the seabed territory licensed to the company for exploration.

Analysis of the samples taken showed an average grade of 17.5 g/t gold, 8.94% copper, 16.84% zinc and 298 g/t silver—much richer than deposits found on land.

While finding rich mineral deposits in PNG is nothing new, the Nautilus discovery and its proposal to begin mining within two years is ground-breaking, 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 sea bottom volcanic geysers which also support the world’s rarest ecosystems which 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 seamounts, off Papua New Guinea (2.8 km basal diameter at 1600 metres water depth), have been found to have 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, chief executive of Nautilus, says mining the sea bottom will be as revolutionary as the development of off-shore oil rigs was in the 1950s.

He contends that deep sea mining will help meet the growing global hunger for minerals, especially the increasing demand from fast-developing India and China.

Last year, Nautilus began prospecting after entering into a collaborative agreement with the Woods Hole Oceanographic Institution to undertake a 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 2000 metres below the surface.

The June 20 announcement came from the Solwara 5, 6 and 7 sites in the waters between New Britain and New Ireland where the first actual mining will be done.

Nautilus says it can extract minerals from the ocean floor through the use of a 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 world’s first attempt at undersea mining began in the late 1950s when American Sam Collins established Tidal Diamonds to mine at sea off the Skeleton Coast of Namibia, where diamonds were more abundant on the seabed than on land.

He mined the ocean floor for nine years and extracted 1.5 million carats of diamond. But the company was literally unable to stay afloat and was bought by the De Beers diamond group in the late 1960s.

In the late 1970s, scientists discovered mineral-rich manganese nodules on the sea bottom of the Atlantic, near submerged volcanic domes and chimney-like vents called ‘black smokers’ because of the plume of black, mineral-rich water spewing like smoke from the chimneys.

While mining the manganese nodules proved to be difficult and expensive for the technology of the time, 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 of more than 5000 metres, also out of reach of contemporary mining at the time.

In a 1994 treaty, International Seabed Authority (ISA) took responsibility for ensuring the benefits of mining in international waters beyond the continental shelf are equitably shared, with emphasis on ensuring developing countries get a fair payment and the protection of the environment from harmful effects. But it does not have any authority when it comes to territorial waters within national boundaries, where local governments have the final say.

While mining active volcanic vents would be too difficult, Nautilus plans to mine up to within 500 metres of active vents using remotely-operated underwater cutters and a hydraulic pump system.

While the technical details remained to be defined, most believe it will be similar to terrestrial strip-mining, removing deposits within the top 20 metres 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 pointed out that the environmental consequences of seabed 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 sensitive chemosynthetic life forms.

He’s also worried 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 ecosystems and the food-chain within the economic zones of other nations. While any country nation has the right to exploit its 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 its claim. They’re also licensed to prospect in national waters of Tonga, Fiji and the Solomon Islands—Pacific islands nations where minerals are in short supply and offshore mining might be seen as a needed boost for the local economies in the future.

The question remains: at what cost, economically and environmentally, will they be mined?