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Net-Acidity <br />4.0 kg CaCO,/ton <br />pH Trend <br />There was a slight decrease in pH over time in the Arabella mine-waste leachate. pH dropped from <br />4.5 after 5 minutes to 4.4 after 18 hours. (-0.1 pH units). This indicates minor net-acid production in the <br />leachate over time. <br />Specific Conductance Trend <br />Leachate from the Arabella mine-waste had low specific conductance with measurements of 30 <br />µ&cm after 5 minutes rising to 52 µS/cm after 18 hours. <br />Sulfate <br />Arabella leachate sulfate concentration was low and rose over time from 0.08 mg/L after 5 <br />minutes to 12 mg/L after 18 hours. <br />Selected Major-Element Trends <br />The concentration of calcium in the Arabella leachate ranged from 0.9 mg/L in the 5-minute leach <br />to 2.1 mg/L after 18 hours. <br />Selected Trace-Metal Trends <br />Following are summaries of selected trace-element trends portrayed in the time study (5-minute <br />vs. 18-hour) of the Arabella mine-waste leachate. <br />Aluminum (AI).-Arabella leachate aluminum concentration decreased slightly over time. The <br />concentration ranged from 35 µg/l, in the 5-minute leachate and dropped to 22 gg/L after 18 <br />hours. <br />Cadmium (Cd).-Slightly elevated concentrations of cadmium were found with <br />concentrations of 0.96 µg/L after 5 minutes, rising to 2.3 µg/L after 18 hours. <br />Copper (Cu).-Arabella leachate copper concentrations increased from 57 µg/L in the 5- <br />minute leachate to 120 pg/L after 18 hours. <br />Iron (Fe).-The Arabella leachate iron concentration was low and a drop in iron <br />concentration was observed over time. Iron concentration dropped from 38 µg/L in the 5- <br />minute leachate to <1 pg/L after 18 hours. <br />Mercury (Hg).-Mercury was not detected in the Arabella leachate. <br />Manganese (Mn).-Manganese was found in the leachate from the Arabella mine-waste. The <br />5-minute concentration was 200 µg/L and rose to 470 µg/L after 18 hours. <br />Nickel (Ni).-Minor concentrations of nickel were found in the leachate with slight increase <br />in leachate concentration over time. 5-minute concentration was 0.6 µg/L; this value rose to <br />1.1 pg/L after 18 hours. <br />Lead (Pb).-There were elevated lead concentrations in the Arabella leachate. Also, leachate <br />lead concentration rose over time from 270 µg/L after 5 minutes to 870 µg/L after 18 hours. <br />Zinc (Zn).-Very high concentrations of zinc were found in the Arabella leachate, and zinc <br />concentrations rose over time. The 5-minute concentration was 230 µg/L; this value rose to <br />510 pg/L after 18 hours. <br />Hageman_SIR_2508.doc 12 7/21/2004 2:50 PM