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Status Report, Robinson Seep Investigation Climax Molybdenum Company <br />Iron concentrations observed in the two piezometers RL -17 and PZ -4 remain above values from <br />monitoring well EVMW -1 S (Figure 5). <br />It is possible that dissolved iron is migrating through fractured bedrock as indicated by its presence <br />in piezometer PZ -04 (3.94 mg /L; completed in bedrock). The dissolved iron may be migrating <br />around or below Robinson Lake seepage collection system, subsequently entering monitoring <br />well EVMW -1 S, which is screened seven feet below the bottom of the Robinson Lake seepage <br />collection system. This occurrence suggests that dissolved iron may be migrating past the <br />Robinson Lake seepage collection system through fractured bedrock. <br />5.3 Manganese <br />Similar to iron, manganese concentrations in monitoring well EVMW -1 S increased through 2013 <br />and then decreased in 2014. Manganese concentrations have remained through 2014 within the <br />bounds of historical EVMW concentrations. Concentrations of manganese in monitoring well <br />EVMW -1 S are also significantly lower than concentrations in Robinson Lake, Robinson Lake <br />Seep, EVS -006 and the two piezometers (Figure 5). <br />Unlike dissolved iron, manganese values in the two piezometers (RL -17 and PZ -04) are similar <br />to reported values from Robinson Lake (Figure 5). <br />Tetra Tech November 2014 <br />