There are about 140 known areas of hydrothermal (hot spring) mineralizations on approximately 1% of the ocean floor that has been explored in detail. About half of these are deposits of copper, zinc, lead, silver and gold in variable amounts that are not unlike deposits being mined on land. Indeed, the land-based mines originally formed in primordial oceans. A few of the presently-forming deposits appear to be of sufficient size (a few million tons) and, based on random sampling by dredge and submersible, of sufficient inferred metal content to be possible candidates for economic recovery (e.g., the Suzette site in the Manus Basin offshore eastern Papua New Guinea with about 15% copper, 3% zinc, 0.1% lead, 130 g/t silver and 21 g/t gold). There are perhaps 10 such deposits that have been discovered to date worldwide, most having lower inferred metal contents than Suzette but nevertheless sufficiently interesting inferred tonnage and metal contents to be candidates for further evaluation (e.g., southern Explorer Ridge offshore western Canada with 2 - 4 million tons giving average analysis of random samples of 3.2% copper, 5.3% zinc, 0.1% lead, 97 g/t silver and 0.6 g/t gold). All of these discoveries have been made in the course of curiosity driven academic research. A concerted well-funded effort with the prime objective of finding large, rich deposits should do better.

Most of the listed deposits are sitting on the seabed as mounds topped by several meter-high spires or chimneys so, not requiring excavation in hard rock, would be relatively easy to recover. A few mounds (notably Middle Valley offshore western Canada) are buried in sediments, which will pose an engineering problem for recovery. All probably have a lower grade zone of disseminated and vein mineralization underneath that, given the anticipated lower grade and mining difficulties, is unlikely to be economic.

Economic Considerations

An important point about these 10 or so potentially mineable deposits is that they are sitting exposed on the seabed. We know where they are and have a pretty good idea of where to find more. All that is needed is sufficient information about true tonnage and grade to make the economic decision to mine based on costs for their development and mining and not for their exploration. The exploration for these deposits has already been done and paid for, although the search for new deposits will surely continue. Another important point is that infrastructure for a mining facility at sea, although likely to be very expensive, is entirely reusable. Contrast this with today's estimated $200 million cost to find and develop a typical 1 to 3 million ton deposit of this type in an established mining region in Canada, such as the Abitibi (G. Riverin, Inmet, 1997) or $80 million just to find a new base metal mine in Australia (Western Mining 1995). Most of the capital infrastructure costs for a mine on land (roads, power lines, perhaps mine buildings and accommodation, shaft, underground development) are left behind when the mine closes. They must be amortized over the life of a single mine which is why land-based industry today is focusing on very large deposits or clusters of deposits in the many tens of millions of tons size, which are rare. In ocean mining, nothing is left behind. There are no expensive shafts and underground workings. Everything is reusable and extremely transportable for deployment at the next site, which may be far away.

Environmental Considerations

Environmental consequences need further study but, at first glance, it does appear that ocean mining for polymetallic sulfides may be less harmful to the environment than equivalent land mining. Two of the biggest problems with land mining are acid mine drainage, caused by ground or rain water reacting with iron sulfides to produce sulfuric acid, and a permanently scarred landscape caused by deep excavations and rock piles. Abundant sulfuric acid cannot form in the oceans because seawater, being alkaline, would instantly neutralize any acids. As explained above, the recovery of most deposits would not leave holes and rock piles on the seabed. A notable exception to this is a deposit like Middle Valley whose recovery would require excavation but in soft sediments. Whether this would have a deleterious affect on the environment requires study.

Loss of habitat through ocean mining is likely to occur just as it does on land in all types of construction activities but the deposits being considered for mining do not harbor large colonies of marine animals. This is in remarkable contrast to the sites that are venting hot water from which the minerals are precipitating on the sea floor. Here, biota are amazingly abundant but such sites would not be mined because the hot water, up to 350 C (~660 F) would destroy the mining machine. In any event, most nations in whose territorial waters mining may be considered, or the United Nations in the case of the international seas, are likely to require environmental assessments before mining is allowed to proceed. The ocean mining industry must embrace these environmental concerns and work closely with appropriate scientists and engineers to ameliorate them.

Scientific Vision

To establish, the preiminate world class corporate entity, for:

•Exploring, evaluating and recovering sea floor deposits of base and precious metals
•Harvesting and screening exotic marine bioresources
•Developing new deep water exploration devices and technologies

Scientific Mission

Identify, map and sample ocean floor deposits capable of being recovered at a profit evaluate the economic viability of deposits for mining determine the environmental consequences of ocean mining and their amelioration develop mining and mineral processing systems for seafloor mining.