Uranium conventional mining

In most respects, conventional mining of uranium is the same as mining any other metalliferous ore, and well-established environmental constraints apply to avoid off-site pollution. From open cut mining, there are substantial volumes of barren rock and overburden waste. These are placed near the pit and used in rehabilitation or shaped and revegetated where they are. 

Nonferrous Metal Production. Nonferrous metal production, which includes the leaching of copper and uranium ores with sulfuric acid, accounts for about 6% of U.S. sulfur consumption and probably about the same in other developed countries. In the case of copper, sulfuric acid is used for the extraction of the metal from deposits, mine dumps, and wastes, in which the copper contents are too low to justify concentration by conventional flotation techniques or the recovery of copper from ores containing copper carbonate and siUcate minerals that caimot be readily treated by flotation (qv) processes. The sulfuric acid required for copper leaching is usually the by-product acid produced by copper smelters (see Metallurgy, extractive Minerals RECOVERY AND PROCESSING). 

The development of thorium-based nuclear power cycles still faces various problems and requires much more R D to be commercialised. As a nuclear fuel, thorium could play a more important role in the coming decades, partly as it is more abundant on Earth than uranium and also because mined thorium has the potential to be used completely in nuclear reactors, compared with the 0.7% of natural uranium. Its future use as a nuclear source of energy will, however, depend greatly on the technological developments currently investigated in various parts of the world and the availability of and access to conventional uranium resources. 

The recovery of the metal values from sources other than freshly mined ores is gaining a lot of interest, Old mine workings are further exploited for their metal values by flooding of the underground workings with leach solutions and recovering the metal by conventional separation processes. Copper and uranium have been recovered in this way. The mine waste... 

The logical explanation for the low percentages of U-235 was that a nuclear fission reaction at the mine must have consumed some of the U-235 isotopes. But how did this happen There are several conditions under which such a nuclear fission reaction could take place. In the presence of heavy water, for example, a chain reaction is possible with unenriched uranium. Without heavy water, such a fission reaction could still occur if the uranium ore and the moderator were arranged according to some specific geometric constraints at the site of the reaction. Both of the possibilities seem rather farfetched. The most plausible explanation is that the uranium ore originally present in the mine was enriched with U-235 and that a nuclear fission reaction took place with light water, as in a conventional nuclear reactor. 

So with >384 GW in operation today (predominantly supplied from conventional uranium mines) present world demand is -70,000 t/a. We can provide an upper bound estimate of demand for 5000 GW of new reactors needing -one million t/a by 2050. Today s estimates of proven uranium reserves af a cosf of < 130/kg is about six million tons (IAEA and OECD-NEA 2005). Even allowing that exploration will likely lead to a doubling or tripling of the resource estimate to, say, 20 MtU, just 2000 reactors operating for 60 years would use all the world s cheapest uranium with present fuel cycles technology. 

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