Hydrothermal vein uranium

The bulk of the world s uranium has been produced historically from (1) lower Proterozoic uraninite placer deposits in quartz-pebble conglomerates, (2) epigenetic uranium deposits in sandstones located in many cases at, or near, groundwater oxidation-reduction interfaces and (3) hydrothermal vein uranium deposits. These three distinctly different geologic environments provided most of the uranium that was produced from the 1940s to the early 1970s and they continue to be important exploration targets in the search for new uranium deposits. 

Bunsenite [1313-99-1] [Named after the German chemist and spectroscopist Robert Wilhelm Bunsen(1811-1899)] (ICSD 9866 and PDF 4-835) NiO M = 74.6928 78.58 wt.%Ni 21.42 wt.% 0 (Oxides and hydroxides) Coordinence Ni(6) Cubic a = 417.69 pm Bl,cF8 (Z=4) S.G. Fm3m P.G. 432 Rock salt type Periclase group Isotropic = 2.37 5.5 6898 (6806) Habit octahedral crystals. Color dark pistachio green. Luster vitreous. Diaphaneity transparent. Streak brownie black Clivage unknown. Fracture unevea Chemical soluble with difficulty in strong mineral acids. Occurrence found in the oxidized zone of hydrothermal nickel-uranium veins along with nickel and cobalt arsenates. 

Coffinite U(SiO, )j (OH),j is a black mineral, important as a uranium ore. It occurs in sandstone deposits and hydrothermal veins. 

In conclusion, uranium deposition is clearly related to two main structural events, both distinguished by widely spaced tension faults with wide vertical displacement.-Two major controls on mineralization have been identified to date— structural (N and N60 E-trending faults) and lithogeochemical (contact between the basement and the Collio formation or its immediate surroundings). The deposit can tentatively be stated to be of the hydrothermal vein type, though some aspects are typical of the vein-like type. ... 

II. In veins of hydrothermal origin, where the vanadium is associated with either uranium or gold. This division includes roscoelite and mottramite. 

By hydrothermal leaching of granitic rocks containing uranium and subsequent deposition, veins with uranium contents of several percent can be formed. This is the case in deposits at Joachimsthal in Bohemia, at Port Radium in Canada, and at Chin-golobwe in Zaire (Congo Kinshasa). 

---