2012-10-01_REVISION - M1977284 (9)

Home Browse Search

Mineral Joe Mine Environmental Protection Plan 34 9.1.3 Economic Geology The Mineral Joe Mine is located in the Uravan Mineral District, which is characterized by its uranium - vanadium ore deposits. These ore deposits contain a distinctive suite of elements including vanadium, molybdenum, and selenium. Other base metals including thallium are present within the ore bodies, but are present in low concentrations. The uranium and vanadium at the Mineral Joe Mine typically mineralizes as roll and tabular layers approximately 3.75 feet thick within the Third Rim of the Salt Wash Member of the Morrison Formation. Ore deposits are typically seen in channel sandstone. Within the Third Rim Sandstone, there are two points of interest for ore deposits. The first appears at a depth of six hundred thirty to six hundred fifty feet near the middle of the Third Rim. The other is seen at a depth of seven hundred to seven hundred twenty five feet closer to the bottom of the Third Rim (Cotter, 1984). The mineralization of the Mineral Joe Mine is much like the rest of the Uravan Mineral District. The uranium occurs in the form of uraninite (pitchblende variety UO2) with traces of coffinite (USiO4OH) filling in the pore space between individual sand grains (Peters, 2011). The uraninite occurs as a more massive, darker colored mineral (Nininger, 1954). When oxidized, these minerals may become much brighter in color and reveal secondary minerals such as corvusite, ravite, and pascoite (Peters, 2011). These oxidation minerals are often seen in conjunction with uraninite in the Uravan Mineral District. The primary vanadium mineral is montroseite (VOOH) in conjunction with vanadium clays and hydromica. Carnotite and tyuyamunite are also commonly seen vanadium minerals after oxidation of the ore occurs. It is possible that other oxidized minerals occur on the Mineral Joe Mine site. The presence of other cations, increased moisture levels, and differing pH levels may enable other vanadium oxides to form over time (Peters, 2011). 9.2 Regional Groundwater System 9.2.1 Hydrostratigraphic Units The regional groundwater system in the Paradox Basin consists of an upper Mesozoic sandstone aquifer and a lower Paleozoic carbonate aquifer (Topper, et al., 2003), separated by a thick sequence of Mesozoic - Upper Paleozoic confining beds and salt confining beds (including the Paradox Member of the Hermosa Formation). The hydrostratigraphic units of the Paradox Valley are shown in Table 20. The upper Mesozoic sandstone aquifer has been called the N- aquifer elsewhere on the Colorado Plateau, where the Navajo Sandstone and Wingate Sandstone are the main water bearing units in the N- aquifer over large portions of Utah and Arizona. Although the Navajo Sandstone and Wingate Sandstone, where present, are the main water- bearing units in the Mesozoic sandstone aquifer, these units are missing from portions of the Paradox Valley.In the Paradox Basin, the Mesozoic sandstone aquifer includes interbedded sandstones, siltstones, and shales which are bounded at the top by the Mancos Shale and on the bottom by mudstones, siltstones, and salt beds (Table 20). As reported by Golder (2009a), along the axis of the eastern Paradox Valley: "Although numerous reports [have been] published to address the regional hydrogeology, no published research has focused on the hydrogeology of the eastern Paradox Valley. Many of the regional studies name the Navajo Sandstone, Wingate Sandstone, and the Entrada Sandstone as important bedrock aquifers. However, these formations are either absent or not known to be water - bearing within the project study area, resulting in almost no relevant published information on groundwater ". -- Golder (2009a) The confining beds between the upper Mesozoic aquifer and the lower Paleozoic aquifer include the Dolores Formation (mudstone and fine- grained sandstone which are not water - bearing), Chinle Formation 4148B.120927 Whetstone Associates •