Selenide mineralization from the uranium ore occurrence Velká (Czech Republic)
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Abstract
An interesting occurrence of selenides, clausthalite and tiemannite, was determined at sample from mine dump material at the abandoned uranium ore occurrence Velká located near Milevsko, southern Bohemia (Czech Republic). Clausthalite forms abundant irregular aggregates up to 300 μm in size between the spherical aggregates of uraninite, which is intensively replaced by coffinite. It is cubic, space group Fm3m, unit-cell parameter refined from PXRD is a 6.1252(2) Å and V 229.80(2) Å3. An irregular minority contents of Cu (up to 0.01 apfu), Tl (up to 0.004 apfu), Ag and Bi (up to 0.003 apfu) were found during study of its chemical composition; determined sulphur contents are very low, about 0.01 - 0.02 apfu S were found only at two point analyses. More rare tiemannite was found as aggregates up to 500 μm accross in fractures of quartz gangue. It is cubic, space group F4-3m, unit-cell parameter refined from PXRD is a 6.0850(2) Å and V 225.31(3) Å3 and its empirical formula is Hg0.99(Se1.00S0.01)Σ1.01. In association with selenides, abundant chalcopyrite and more rare pyrite with minor selenium contents were determined.
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References
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