Minerals Report - International Seabed Authority

percent copper. In addition, small but significant amounts of silver and gold
had been found in the deposits.
In connexion with the mining of this deposit, Professor Rona described
the efforts by the German geophysical company Preussag and the
Governments of Saudi Arabia and Sudan to do this with the assistance of
slides. Dr. Rona noted that the deposit occurred within the Exclusive
Economic Zones of Sudan and Saudi Arabia. He said that in 1979, a pre-pilot
feasibility-mining test, using an adapted offshore oil-drilling vessel (the
Sedco) was carried out. Given the consistency of the brines that Dr. Rona
described as Jello, a hydraulic suction cutter head was used. Dr. Rona stated
that this technological configuration was successful in sucking up the
metalliferous brines and raising them up to the surface vessel. On the surface
vessel, which was equipped for processing through flotation techniques, Dr.
Rona explained that by bubbling air through the sediments a significant
fraction of the zinc was separated out from the slurry. While the feasibility of
mining was demonstrated, the economic feasibility of the operation is yet to
be demonstrated.
In 1978, a French/Mexican/American expedition, using the French
manned submersible CYANA, made a transit across a portion of the global
submerged volcanic mountain range called the East Pacific Rise, off Mexico
just south of the Gulf of California. Dr. Rona stated that the expedition was
planning to do a standard geological transit in water depth of about 2,000
metres across the submerged volcanic mountain range. In the course of this
transit, Dr. Rona informed participants that the expedition encountered
curious green mounds, up to about 10 metres high, that they were very
different from the normal volcanic rocks of the deep sea floor. Out of
curiosity, he continued, the expedition sampled the material and then
continued its traverse, describing the geology and structure of the East Pacific
rise. At IFREMER in France, a visiting geologist saw these rocks, and asked
where the rocks had been recovered. Dr. Rona said that the green rocks
turned out to be massive sulphides rocks, the first massive sulphides
specimens to be found in the deep ocean basin. Professor Rona pointed out
that many scientific discoveries are made by chance, serendipity. He
explained that the scientists in the expedition immediately came together and
wrote a classic paper that made the cover of the prestigious international
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