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JD -6 Mine Environmental Protection Plan 10 <br />deionized water until the pH was 5.00 (± 0.05). The solution and samples were then added to a sealed <br />container in 20:1 ratios (solution:sample)' and tumbled for 18 hours at 30 rotations per minute (rpm) (± 2 <br />rpm). The resulting solution was decanted, filtered (0.45 gm), and analyzed. <br />SPLP results indicated that metal concentrations were below the detection limit in 81% (56 of 69) of the <br />metals results for representative samples of ore and waste rock (Table 6). <br />The waste rock SPLP leachates met the Federal drinking water standards (maximum contaminant levels <br />[MCLs], secondary maximum contaminant levels [SMCLs]), and Colorado domestic water supply <br />standards for all metals. Gross alpha activity in the SPLP leachate from the waste rock composite sample <br />exceeded MCLs by a factor of four. Sulfate and TDS exceeded secondary SMCLs by a factor of three and <br />two, respectively. Vanadium concentrations in the SPLP leachate exceeded the Colorado agricultural <br />standard of 0.1 mg /L by a factor of five. <br />The representative ore pile SPLP leachates from the nearby JD -8 Mine exceeded MCLs for arsenic, <br />selenium, fluoride, and gross alpha, SMCLs for sulfate and TDS, Colorado drinking water standards for <br />molybdenum, and the Colorado agricultural standard for vanadium (Table 6). No ore will be stored above <br />ground at the JD -6 Mine permit area, according to the mine plan. <br />Based on these results, the constituents of potential concern for the waste rock pile are gross alpha, sulfate, <br />TDS, and vanadium. Further analysis was performed to determine whether or not these constituents would <br />be mobile in the environment, based on site - specific precipitation rates, infiltration rates, and groundwater <br />and surface conditions (Section 5.4). <br />' Samples for the core comparison were leached using a 2:1 ratio (solution:sample) to generate leachates with higher concentrations <br />that could be more easily compared. <br />2 Federal drinking water standards, maximum contaminant levels, Colorado domestic water supply standards, and other standards <br />discussed in Section 5.3.3 and 5.4.1 are used as screening levels to identify COPCs. These standards apply to groundwater in the <br />environment and are not directly applicable to laboratory leachates. <br />4148A.120927 Whetstone Associates • <br />