SEABED AUTHORITY HEARS LATEST SCIENTIFIC FINDINGS

ON NEW DEEP-SEA MINERALS

(Reissued as received.)

KINGSTON, 7 August (International Seabed Authority) -- Three marine geologists and a biologist presented to the International Seabed Authority in Kingston today an up-to-date survey of scientific information about polymetallic massive sulphide deposits and cobalt-rich ferromanganese crusts – recently discovered mineral resources found in seabed areas underlying both national and international waters of the world’s oceans.

The presentations were made at a special all-day seminar – the first of its kind – organized for the information of delegations to the Authority’s current annual session.  The Council of the Authority is to take up this topic next week, in line with the Authority’s mandate of organizing and controlling all mineral-related activities in the international seabed area beyond national jurisdiction.

The geologists described the rich concentrations of valuable metallic ores in these deposits, notably of cobalt and other rare metals used in making specialty steels and many other products.  They said, however, that mining of these deposits was likely to occur first in shallower waters within the exclusive economic zones of coastal States.  The biologist told of the exotic animals living exclusively in the sulphur-rich waters around underwater hot springs that are the source of these deposits – unique life forms that might provide not only proteins for new medicines and industrial products but also give clues to the origins of life on earth.

A fifth speaker discussed the results of a technical workshop held by the Authority last week in Kingston, which proposed projects to investigate four aspects of research into the effects of seabed mining on the marine environment.

Scientific Presentations on Newly-Discovered Minerals

Peter A. Rona, Professor of Geological and Marine and Coastal Sciences at the Institute of Marine and Coastal Sciences, Rutgers University, New Jersey, said rich concentrations of gold, silver, copper, zinc and lead were found in huge mounds of polymetallic sulphide deposits on the ocean floor, first discovered in the 1970s.  Most of the sites were on the East Pacific Rise, the Southeast Pacific Rise and the Northeast Pacific Rise in depths up to 3,700 metres. At least 50 active hot spring sites for cobalt-rich deposits were known, in areas representing 5 percent of the ocean floor.

Seafloor polymetallic sulphide deposits had recently attracted the interest of the international mining industry due to the high concentration of base and precious metals, he observed.  Polymetallic massive sulphide deposits in amounts up to 100 million tonnes existed on the seafloor in a variety of tectonic settings, including mid-ocean ridges, back-arc rifts and seamounts.

Dr. Rona noted that marine mining of sulphide deposits appeared to be feasible in this decade for the following reasons:  (1) they contained high grades of gold and base metals, (2) sites were commonly within the territorial waters of a coastal State, and (3) sites were often in shallow water, although technology existed for mining in deeper water.

The Government of Papua New Guinea had granted the first two marine exploration licences for seafloor sulphide deposits to an Australia-based mining company in 1997, he noted.  The licenses covered an area of about 5,000 kilometres of the Manus Basin and included the Vienna Woods (central Manus Basin) and the Pacmanus (eastern Manus Basin) sites, on the west side of New Ireland.

Turning to cobalt-rich ferromanganese crusts, he explained that they were formed on the seafloor on the flanks and summits of seamounts, ridges, plateaus and abyssal hills where rocks had been swept clean of sediments, intermittently, over millions of years. Occurring at water depths of up to 3,000 metres, crusts were important as potential sources of cobalt, but also of titanium, cerium, nickel, platinum, manganese and other minerals.

Peter M. Herzig, Chair for Economic Geology and the Leibniz Laboratory for Applied Marine Geology at the Mineralogy Institute of the Technical University Bergakademie Freiberg, Germany, spoke of the nature and resource potential of polymetallic massive sulphide deposits on the seafloor. He said that in 1979 at the East Pacific Rise, off the coast of California, such deposits had been found to contain high concentrations of base and precious metals.  It was this discovery that had stimulated the interest of the international mining industry.  Since then, some 200 sites had been identified in the world's oceans -- mostly along the west coast of North America and throughout the Pacific Ocean, along with several in the mid-Atlantic and three in the Indian Ocean.

He explained that sulphide deposits were found in two types of ridges located at the seafloor spreading centers where the earth’s tectonic plates were moving apart, allowing hot magma from beneath the crust to rise near the surface.  Deposits at back-arc ridges of the western and southwestern Pacific differed in chemical and mineralogical composition from those at the globe-encircling mid-ocean ridges. The first samples taken from back arc ridges had been found to contain significant amounts of gold -- as much as 30 parts per million (ppm)-- and some intracontinental back arc ridges had yielded deposits with over 2,000 ppm of silver.

He spoke of plans for a research cruise to the Conical Seamount scheduled for September 2002.  This area, in the territorial waters of Papua New Guinea, had the record for the highest percentage of gold ever found in a sulphide deposit -- 230 ppm.  The average gold yield there had been 26 ppm, about twice as high as anything else seen so far.  Conical Seamount was unique in that it was not exclusively formed by the mixing of hydrothermal seawater with ambient seawater like most sulphide deposits, but as a response to direct input of magmatic fluid, which had a high concentration of metals.  Conical Seamount was believed to be the submarine analogue of the gold deposit located on nearby Lihir Island.  In addition to the high gold content, other advantages of Conical Seamount included direct access to a processing plant, its shallow water location, and the fact that it was sediment-free, so that mining was likely to have less environmental impact than in places where potentially damaging sediment plumes would be discharged into the sea during the extraction process.

The advantages of seafloor sulphide mining over land mining, as Dr. Herzig saw them, were that the entire mining system was portable, no infrastructure was necessary, there were no shafts or mines to be developed and there were no acid mine draining or waste disposal issues.  However, not enough was known about these deposits and systematic drilling was required to gauge resource potential and economic feasibility. 

James R. Hein, Senior Geologist of the United States Geological Survey and President of the International Marine Minerals Society, described the global distribution, composition and origin of cobalt-rich ferromanganese crusts, and the research being done on this resource.  Illustrating the age of these deposits, he said that if two centimetres of crust were broken off, it would take some 10 million years for the lost segment.to be replaced, compared to a broken chimney or smoker from a hydrothermal vent, which restored itself in a matter of weeks.  Thus, the study of ferromanganese crusts was useful not alone for their economic potential but also for what they might tell about the past 60 million years of oceanic history.

Ferromanganese crusts were found on hard-rock substrates throughout the ocean basins and varied in thickness from 1 millimetre to 25 centimetres, he continued.  They occurred mostly on submarine volcanoes, extinct for millions of years, known as seamounts.  They are found at a water depth of 400 to 4,000 metres, with the richest at depths of between 800 and 2,200 metres. In deeper water the crusts tended to be thinner, as gravity-related processes destroyed them.

Mr. Hein estimated that about 6.35 square kilometres, or 1.7 per cent of the ocean floor, was covered by cobalt-rich crusts, translating to some 1 billion tonnes of cobalt.  Nearly 50 research cruises to investigate these crusts had been undertaken so far, mostly in the Central Pacific.

Little was known about the biological communities of the seamount beyond the fact that they were complex and variable, he stated.  Two seamounts at the same level could have completely different biological components.  They were believed to be low density and low diversity communities, especially below the oxygen-minimum zone (OMZ), which was good news in terms of the potential environmental impact of exploiting these crusts. 

Discussing strategies for investigating crusts, he said the best course would be to explore large volcanic edifices shallower than 1,500 metres and older than 20 million years that were not capped by large atolls or reefs.  They should be areas of strong bottom currents to keep the seamount clear of sediment and should have a well-developed OMZ.

Biology of Hydrothermal Vents

S. Kim Juniper, professor in the Department of Biological Sciences of the University of Quebec at Montreal and a researcher at the University’s Geochemistry and Geodynamics Research Centre (GEOTOP), discussed the potential effects of mining on hydrothermal vent ecosystems – the deep-sea animal community dependent on the hydrogen-sulphide-laden waters surrounding sulphide deposits.  He spoke of the “surprising intimacy” that existed between vent fauna and mineral deposits in the deep ocean.  According to Mr. Juniper, the fauna directly affected by mining would be damaged or destroyed and their habitat would be radically changed.

Scientists studying hydrothermal vent ecosystems since the late 1970s had so far identified 500 animal species, more than 90 percent of which were found only in these habitats, he stated.   They included some highly specialized animals with unique genetic resources that might well be important to mankind.  For example, he cited the polymerase enzymes used in DNA fingerprinting as a significant resource from hydrothermal vent fauna.  Chief concerns in regard to the selection of mining sites should include the degree of loss of different types of vent habitats, sediment-plume fallout in areas not directly mined, the geographic range of affected species and the uniqueness of local gene pools. 

Mr. Juniper said careful consideration must be given to preservation of the “mother populations” in multi-species communities.  There was evidence that biodiversity within a given region was greatest at larger, long-lived hydrothermal sites, in keeping with what had been observed in other ecosystems.  Mother populations were thought to be critical to the maintenance of vent-species biodiversity within a region.  However, the same long-lived hydrothermal sites were also the most likely locations for accumulation of large sulphide deposits, and therefore would be prime targets for mining.  Scientists believed that only the establishment of protected areas would prevent the eradication of species.

Marine Environmental Research

Alex D. Rogers, Principal Investigator for Biodiversity Research at the British Antarctic Survey, United Kingdom, provided an overview of some of the outcomes of the technical workshop held at the Authority from 29 July to 2 August, suggesting projects for marine environmental research.

Dr. Rogers pointed out that scientific work in the Clarion-Clipperton Fracture Zone of the Central South Pacific Ocean, where most of the world’s known deposits of polymetallic nodules are located, had shed some light on the environmental impact of deep-sea mining, regardless of the methods employed.  However, more specific information was needed about many aspects of the marine environment and the fauna inhabiting the ocean floor.  He identified four main areas -- all dealing with the potential environmental impact of nodule extraction from the deep seabed -- in which research would be carried out.

The first project, due to start next February, involves research into biodiversity and species ranges in the nodule areas where nodules, a topic which Dr. Rogers noted was poorly understood.  Some scientists estimated that there might be anywhere between 1 million and 100 million species living on the ocean floor that were unknown to science.  Without further knowledge it would be difficult to predict how these life forms would be affected by mining. Due to the inadequacy of species identification based on morphological study, proper investigation would require the use of molecular testing of deoxyribonucleic acid (DNA), the foundation material of genetics. 

Further research would also be undertaken on the recolonization process taking place after the disturbance created when nodules were gathered from the seafloor, to examine the rate at which disrupted animal communities returned to

the pre-mining state and the specific patterns and means by which they did so. Dr. Rogers described a device that is lowered onto the seabed to record photographically what changes take place over a long period of time.

Two more projects would investigate the impacts of mining detritus on the pelagic (free-swimming or floating) communities above mine sites, and natural variability in deep-ocean ecosystems over space and time.

Dr. Rogers stressed the importance of international collaboration in research on the oceans.

(A summary of the Workshop on Prospects for International Collaboration in Marine Environmental Research to Enhance Understanding of the Deep-Sea Environment, held in Kingston, appears in press release SB/8/2 of 5 August.)

* *** *