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Uranium Distributions in the Earths Crust The following table is from Deffeyes & MacGregor, "World Uranium resources" Scientific American, Vol 242, No 1, January 1980, pp. 66-76.
The total abundance of Uranium in the Earth's crust is estimated to be approximately 40 trillian tonnes. The Rossing mine in Nambia mines Uranium at an Ore concentration of 300 ppm at an energy cost 500 times less than the energy it delivers with current thermal-spectrum reactors. If the energy cost increases in inverse proportion to the Ore concentration, shales and phosphates, with a Uranium abundance of 10 - 20 ppm, could be mined with an energy gain of 16 - 32. The total amount of Uranium in these rocks is estimated to be 8000 times greater than the deposits currently being exploited.
+toolbarUranium Distributions in the Earths Crust The following table is from Deffeyes & MacGregor, "World Uranium resources" Scientific American, Vol 242, No 1, January 1980, pp. 66-76.
| type of deposit | estimated tonnes | estimated ppm  |
|---|---|---|
| fresh water | 2 x 106 | .0001-.001 |
| ocean water | 2 x 1010 | .0002-.001 |
| oceanic igneous crust | 8 x 1011 | .1-.2 |
| evaporites, siliceous ooze, chert | 6 x 1012 | .2-1 |
| fossil placers, sand stones | 8 x 107 | 1,000-2,000 |
| average crust | 3 x 1013 | 1-3 |
| Vein deposits | 2 x 105 | 10,000+ |
| shales, phosphates | 8 x 1011 | 10-20 |
| volcanic deposits | 2 x 109 | 100-200 |
| Pegmatites, unconformity deposits | 2 x 106 | 2,000-10,000 |
| black shales | 2 x 1010 | 20-100 |
| lower grade fossil placers,sandstones | 1 x 108 | 200-1,000 |
| granites | 2 x 1012 | 3-10 |