What is Uranium?

Uranium, chemical symbol U, is a radioactive metallic element of high specific gravity, which occurs naturally in most rocks, soil, and the ocean. It is 500 times more abundant than gold and is as common in the earth's crust as tin, tungsten, and molybdenum. Uranium is found as an oxide, uraninite or mixed oxide, pitchblende or complex salt such as brannerite (oxide of uranium, rare earths, iron and titanium), coffinite (uranium silicate), and carnotite (hydrated potassium uranyl vanadate).

Uranium is insoluble in water and non-flammable, and occurs in nature as a mixture of Wee isotopes _ U23R (99.28%), U'" (0.71%) and U2:>'(O.OI%).

U235 is the only naturally occurring uranium element that can be readily split (nuclear fission) yielding the large amount of energy which is the basis for nuclear power. The vast majority of nuclear power reactors are fuelled by 'enriched' uranium where the U235 content has been raised from 0.71 % to approximately 3.5%. Uranium covers three sectors, as a commodity, source of power, and strategic metal.

Where is Uranium Found?

Uranium occurs in a variety of different geological environments; in igneous, hydrothermal and sedimentary settings. There are 14 major categories of uranium deposits defined by these settings. This article covers only the four major environments from which the majority of western world supply originates.

Over 33% of the world's uranium resources are in unconformity-related deposits such as the Athabasca and Thelon Basins, Canada and the Pine Creek Geosyncline (Alligator River deposits), and Rudall River Areas in Australia. Hydrothermal breccia iron-oxide-hosted deposits (IOCG) such as Olympic Dam in Australia account for approximately 30% of world uranium resources, sandstone (roll-front) deposits such as found in the Western Cordillera of the United States constitute over 18% of world uranium resources and paleoplacer (quartz-pebble conglomerate) deposits such as those at Elliot Lake, Ontario and Witwatersrand in South Africa constitute approximately 13% of world uranium resources. The grades of unconformity-hosted deposits can be quite high grade, to over 10% U,O., while deposits hosted in sandstones and IOCG deposits are large but generally low grade averaging below 0.5% U,O •.

Economically at a grade of 0.1 % U,O. with the uranium price at U5$30.00 per pound this equates to approximately U5$66.00 per tonne of rock. At a grade of 1 %, the value increases to U5$660 per tonne as 1% equates to just over 22 pounds in one tonne of rock.

Uranium generally occurs as the primary oxide minerals uraninite (U02) or mixed oxide, pitchblende (U,O.). A variety of other minerals can occur depending on the type of deposit including carnotite(uranium potassium vanadate), uranium titanates (davidite, brannerite, absite), and uraniwn niobates (euxenite, fergusonite, samarskite). Many secondary uraniwn minerals are brigbdy colored and fluoresce including gununire (secondary hydrared uraniwn oxides), autunite, saleeite, torbernire (hydrated phosphates) and coffinite, uranophane, sklodowskite (hydrated uraniwn silicates).

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