Plans are afoot to exploit some of the rich min­eral deposits in Siberia; although new technologies will have to he developed to make this feasible. Some of the ore deposit in Siberia has unusual combinations of minerals that can not separated using existing technologies.

Is there a possibility that currently unknown mineral deposits will be discovered at some future time? The U.S. Geological Survey thinks that undiscovered mineral despites may exist particularly in developing countries where detailed geological surveys have nor been performed. It is likely that a detailed ailed survey of the western portion of South America, along the Andes Mountains, will reveal mineral deposits. Geologists also presume that min­erals will be found in the Amazon Basin, although in many ways the rain forest makes these despites as certain areas deep in the rain forest to ascertain the likelihood of deposits being present creates logisti­cal problems and poses a grave environmental threat.

Geologists also consider it likely that deep de­posits, those buried 1,000 or more meters in the Earth's crust, will someday be discovered and ex­ploited. The special technology required to mine deep deposits is not yet available.

Minerals from the Oceans

The mineral reserves of the oceans may also pro­vide us with future supplies. The sea floor may be mined, particularly where minerals have accumu­lated in the loose ocean sediments. Alternatively, minerals could be extracted from seawater.

Ocean Floor Although large deposits of minerals lie on the ocean floor, the expense of obtaining them is prohibitive, given the current technology. These deposits may never be economical to ac­quire, and the environmental impacts of mining them are another obstacle to their exploration and development (see Focus On: Safeguarding the Seabed).

Significant deposits of iron, copper, and zinc and lesser amounts of gold and silver were discovered in the Red Sea in the 1960s. The governments of Saudi Arabia and Sudan, both of which border the Red Sea, are investigating the possibility of a joint venture to mine these deposits by dredging the floor of the Red Sea and vacuuming the loose sediments up a tube to a ship. The minerals in this slurry would then be refined on land.

Manganese nodules—small rocks the size of potatoes that contain manganese and other miner­als, such as iron, copper, and nickel—are wide­spread on the ocean floor, particularly in the Pa­cific. According to the Marine Policy Center at the Woods Hole Oceanographic Institute, the estimates of these reserves arc quire large. However, dredging manganese nodules from the ocean floor would adversely affect sea life. Further, it is not clear which country, if any, has the legal right to these minerals, which are in international waters. Monitoring and policing their re­moval would almost certainly require international cooperation.

Seawater: Seawater, which covers approximately three-fourths of our planet, contains many different dissolved minerals. The total amount of minerals available in seawater is staggering, but their con­centrations are very low. Currently, sodium chlo­ride (common table salt), bromine, and magnesium can be profitably extracted from seawater. It may be possible in the future to profitably extract other minerals from seawater and concentrate them; hut current mineral prices and technology make this impossible now.

Advanced Mining Technology

We have already mentioned that special technolo­gies will be needed to mine minerals in inaccessible areas such as Polar Regions and deep deposits. Capi­talizing on large, low-grade mineral deposits throughout the world will also require the develop­ment of special techniques. As minerals grow scarcer, economic and political pressure to exploit low-grade ores will increase. Obtaining high-grade met­als from low-grade ores is an expensive proposition, in part because a great deal of energy must be ex­pended to obtain enough ore. Future technology may make such exploitation more energy-efficient, thereby reducing costs.

Even if advanced technology makes obtaining minerals from low-grade ores feasible, other factors may limit exploitation of this potential source. In arid regions, the vast amounts of water required during the extraction and processing of minerals may be the limiting factor. Also, the environmen­tal costs may be too high, because obtaining miner nls from low-grade ores causes greater land disrup­tion and produces far more pollutants than does the development of high-grade ores.