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<br />d. Humidity cell testing <br />e. EPA Method 1312 leaching. <br />These test methods and the results of each are discussed in the various documents named above. In <br />all cases, the test results were interpreted by the Division, and the operator's or their consultants' <br />interpretations were examined. <br />For the Acid Base Accounting tests total sulfur analyses were assumed to record sulfide sulfur <br />unless analyses showed a significant abundance of sulfate sulfur. Organic sulfur reports were ignored <br />as such is unlikely to occur in these rock units, and also because all such analyses were very ]ow and <br />are probably an artifact of analytical discrepancies. Acid production potentials that were less than 3 <br />times greater than the acid neutralization potential were considered to represent postl mining conditions <br />that could produce acid rock drainage. <br />Several tests were run by BMRI to evaluate metal behavior in the post-mining environment. <br />These included Batch Leach Tests and XRF analyses. For the XRF analyses, the concentrations of <br />siderophilic elements (Fe, As, Co, Cu, Pb, Mo, Ni and Zn) were compared with total sulfur to <br />determine whether metals were likely to be present either as sulfide phases or oxide phases or as trace <br />elements in the major rock forming minerals. (The rate of weathering of metal oxides or trace <br />elements from the rock forming minerals would be far lower than from sulfide ar»nerals.) Because <br />sulfur is present in quantities sufficient to account for some sulfide mineralisation, and because <br />significant quantities of sulfate minerals are not reported for these rock units, sulfide minerals appear <br />to be the most likely mineralogical components to contain most of the metals. Concentrations of the <br />regulated metals were compared to average crustal abundances (as recorded in the American <br />Geological Institute Data Sheets), and if metals were present in concentrations greater than 2 limes <br />crustal abundance, it was assumed that such meta] might be mobile in the post-mining environment. <br />For the batch samples, a composite sample was compiled from cores. Leachate water was <br />adjusted to a pH of 5.5 with HCI, applied at a water :rock ratio of 2 : 1, and bottle rolled for 24 <br />hours. <br />For the Method 1312 analyses, the Division compared the results with state water quality <br />standazds rather than with the proposed regulatory levels suggested for method 1311, as demonstrated <br />by the operator. This more conservative interpretation was selected in order 1o highlight potential <br />needs for protection of the rock mass or for groundwater monitoring, rather than to predict any <br />absolute geochemical consequence to the environment. <br />There are no established uses for groundwater in the vicinity of the West Pit currently. <br />However, the results of all of the metals availability tests were compared with water quality standards <br />for drinking water and agriculture, as these two uses could apply to the groundwater in the vicinity <br />of the West Pit at some point in the future, and the Division's policy is to consider all present and <br />potential beneficial uses. <br />4 <br />