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SR-I I (Ike #1 Mine) Designated Mining Operation <br /> January 31, 1995 - Page 3 <br /> Pertinent Geology and Geochemistry <br /> The mineralogy and geochemistry of uranium and vanadium minerals <br /> have received a substantial amount of research since the mid <br /> 19501s. The geology of the Uravan Mineral Belt and its vanadium- <br /> uranium deposits are well described in the literature, also. <br /> Furthermore, the Slick Rock District (where the Ike #1 Mine is <br /> located) is probably the most intensely studied area of the UMB. <br /> Although most of the published literature I have available is <br /> concerned with the geochemistry from an exploration point of view, <br /> it is still applicable since it also covers the solubility of <br /> uranium and vanadium in the surficial and near surface <br /> environments. Steve Landau may have other, more recent documents <br /> specifically on mine wastes. <br /> Long recognized as pertinent references in the field are Garrels <br /> and Larsen, compiles U.S.G.S. Prof. Paper 320, 1959 and Hostetler <br /> and Garrels, 1962 . All later works on the subject always reference <br /> these plus Garrels and Christ, 1965. Extensive work was done on <br /> the Slick Rock District by Shawe, 1968, 1976 and Shawe, et. al. , <br /> 1968. The following summarizes the work of these and other experts <br /> concerning the solubility, transport and precipitation of uranium <br /> and vanadium in the surficial environment. The chart on the next <br /> page illustrates these processes. <br /> Vanadium is a fairly common trace element in the upper lithosphere <br /> (about 150 ppm - only 20 elements occur more abundantly) . <br /> Uranium's crystal abundance is about 3 ppm. These two elements are <br /> similar in some aspects of their geochemistry, but differ in other <br /> respects. It is their co-existence in the Salt Wash sandstones <br /> that is pertinent to this discussion. <br /> Uranium in the U+4 state (uranous) commonly occurs as its own <br /> minerals as oxides (Pitchblende, uraninite) , silicates (coffinite) <br /> and phosphates. It can also substitute in other rock forming <br /> minerals; however, that is often difficult because of its large <br /> ionic size and charge. U+4 can occur in loosely held positions in <br /> clays and zeolites or absorbed on other crystal faces. Regardless <br /> of its mode of occurrence, U+4 is not soluble in normal surface \\y0 <br /> waters until it is oxidized to the U+6 state (uranyl) . t0ti <br /> �ti b <br /> The common uranium minerals in the primary ore of the Slick Rock \� \e <br /> District are uraninite (UO2) and coffinite (U(SiO4) ) . Uraninite ;W ,Nr <br /> oxidizes by a pseudomorphic process to mixed UO2•UO3 mineral, which JDti <br /> will still not easily dissolved in pure water. Coffinite, which is T-t6 <br /> more difficult to oxidize than uraninite, also oxidizes much more <br /> rapidly than it dissolves. Other components are necessary in the &t <br /> aqueous system in order to dissolve U+6once it is formed by w� T1 <br /> oxidation. The most important is COZ, which will be present in <br /> small amounts in rain water. U+6 readily hydolyses to the uranyl l <br /> cation, UO2+2 which can then form stable, soluble dicarbonate and J11j1 Colltricarbonate complexes. orb <br /> psp�FC- <br /> F\&DN <br />