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Mineral Joe Mine Environmental Protection Plan 13 <br />5.4 Environmental Protection Evaluation <br />The SPLP testing (Section 5.3.3.3) identified seven constituents in waste rock as a constituent of potential <br />concern (COPC) at the Mineral Joe Mine based on SPLP leachate concentrations exceeding groundwater <br />standards. Since no ore pile is available for testing at the Mineral Joe Mine, the SPLP results from the <br />nearby JD -8 Mine were evaluated instead, and eight constituents were identified as possible future COPCs <br />for the Mineral Joe Mine. These constituents are listed in Table 7 and are described individually in Section <br />5.4.1, below. The potential for transport to groundwater is discussed in Section 5.4.2. <br />Table 7. Constituents of Potential Concern in Mineral Joe Waste Rock Pile and JD -8 Ore <br />Pile <br />Notes <br />HHS = Human health standard <br />DW = Drinking water standard <br />= Constituent did not exceed standards shown <br />D = Sample required dilution <br />CO = Colorado standard, no federal drinking water standard exists for molybdenum <br />5.4.1 COPC Chemistry and Occurrence in the Environment <br />5.4.1.1 Arsenic <br />The SPLP results for the Mineral Joe waste rock exceeded the drinking water standard for arsenic by a <br />factor of four and met the Colorado groundwater agricultural standard. Similarly, SPLP results from the <br />nearby JD -8 Mine ore pile representative composite samples exceeded the drinking water standard by a <br />factor of 2.8 and met the Colorado groundwater agricultural standard. <br />Arsenic occurs naturally in groundwater wells in the Paradox Basin above the drinking water standard of <br />0.01 mg /L. Golder (2009) reported that, in background monitoring wells at the Pifion Ridge site, arsenic <br />concentrations were above the domestic supply standard in samples from six pumping wells, exploratory <br />holes, and a domestic well. The highest background arsenic concentration reported in the Pifion Ridge <br />wells (0.0177 mg/L) was measured in the sample from PW -1. <br />Welch, et al., (1988) reported that natural occurrences of groundwater with moderate to high arsenic occur <br />throughout the western United States, and that high concentrations of arsenic are associated with basin -fill <br />deposits of alluvial - lacustrine origin, particularly in semiarid areas. Based on over 7,000 groundwater <br />samples for arsenic in the western US, the research also found that, in addition to basin -fill deposits, arsenic <br />is associated with volcanic deposits, uranium and gold mining areas, and geothermal systems. <br />While the source of arsenic in the Paradox Valley has not been definitively identified, in Lisbon Valley <br />(located on the Colorado Plateau 22 miles west of the Mineral Joe Mine), the alteration of the mineral <br />4148B.120927 Whetstone Associates • <br />Underground <br />Waste Rock <br />Ore (from JD -8 Mine) <br />Water Quality Standards <br />SPLP <br />SPLP <br />SPLP <br />Federal Federal <br />MCL SMCL Groundwater <br />Parameter <br />MJ WRP <br />Agricultural <br />JD-8-ROPC1 <br />JD-8-ROPC2 <br />(Colorado (Colorado Standards <br />HHS) DW Table 2) <br />Arsenic <br />0.042 <br />0.028 <br />0.028 <br />0.01 0.1 <br />Molybdenum <br />0.3 <br />0.6 <br />0.5 <br />0.035 0.2 <br />Selenium <br />0.11 <br />0.14 <br />0.12 <br />0.05 0.02 <br />Gross alpha (pCi/L) <br />97.6 <br />88 <br />81.4 <br />15 <br />Fluoride <br />- -- <br />- -- <br />6.9 <br />4 2 2.0 <br />Sulfate <br />737 <br />992 D <br />1,010 D <br />250 <br />TDS <br />1240 <br />1,540 <br />1,570 <br />500 <br />Vanadium <br />16 <br />14 <br />19 <br />0.1 <br />Mineral Joe Mine Environmental Protection Plan 13 <br />5.4 Environmental Protection Evaluation <br />The SPLP testing (Section 5.3.3.3) identified seven constituents in waste rock as a constituent of potential <br />concern (COPC) at the Mineral Joe Mine based on SPLP leachate concentrations exceeding groundwater <br />standards. Since no ore pile is available for testing at the Mineral Joe Mine, the SPLP results from the <br />nearby JD -8 Mine were evaluated instead, and eight constituents were identified as possible future COPCs <br />for the Mineral Joe Mine. These constituents are listed in Table 7 and are described individually in Section <br />5.4.1, below. The potential for transport to groundwater is discussed in Section 5.4.2. <br />Table 7. Constituents of Potential Concern in Mineral Joe Waste Rock Pile and JD -8 Ore <br />Pile <br />Notes <br />HHS = Human health standard <br />DW = Drinking water standard <br />= Constituent did not exceed standards shown <br />D = Sample required dilution <br />CO = Colorado standard, no federal drinking water standard exists for molybdenum <br />5.4.1 COPC Chemistry and Occurrence in the Environment <br />5.4.1.1 Arsenic <br />The SPLP results for the Mineral Joe waste rock exceeded the drinking water standard for arsenic by a <br />factor of four and met the Colorado groundwater agricultural standard. Similarly, SPLP results from the <br />nearby JD -8 Mine ore pile representative composite samples exceeded the drinking water standard by a <br />factor of 2.8 and met the Colorado groundwater agricultural standard. <br />Arsenic occurs naturally in groundwater wells in the Paradox Basin above the drinking water standard of <br />0.01 mg /L. Golder (2009) reported that, in background monitoring wells at the Pifion Ridge site, arsenic <br />concentrations were above the domestic supply standard in samples from six pumping wells, exploratory <br />holes, and a domestic well. The highest background arsenic concentration reported in the Pifion Ridge <br />wells (0.0177 mg/L) was measured in the sample from PW -1. <br />Welch, et al., (1988) reported that natural occurrences of groundwater with moderate to high arsenic occur <br />throughout the western United States, and that high concentrations of arsenic are associated with basin -fill <br />deposits of alluvial - lacustrine origin, particularly in semiarid areas. Based on over 7,000 groundwater <br />samples for arsenic in the western US, the research also found that, in addition to basin -fill deposits, arsenic <br />is associated with volcanic deposits, uranium and gold mining areas, and geothermal systems. <br />While the source of arsenic in the Paradox Valley has not been definitively identified, in Lisbon Valley <br />(located on the Colorado Plateau 22 miles west of the Mineral Joe Mine), the alteration of the mineral <br />4148B.120927 Whetstone Associates • <br />