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Technical Memorandum <br />To: John Hamrick and Randy Whicker, Cotter Corporation (N.S.L) <br />From: David Levy, AMEC Earth & Environmental <br />Tel: (303) 630 -0788 <br />Fax: (970) 669 -0003 <br />Date: October 10, 2011 <br />ame0 <br />Subject: Technical Assessment as to the Probable Source of Uranium in Sump No. <br />10, Schwartzwalder Mine, Jefferson County, Colorado. <br />1.0 INTRODUCTION <br />Cotter Corporation (N.S.L.) ( "Cotter ") recently informed the Division of Reclamation, Mining & <br />Safety (DRMS) that it has discovered elevated concentrations of uranium in alluvial groundwater <br />near the Old Emergency Discharge Pond located at the Schwartzwalder Mine, which is being <br />treated in the alluvial groundwater and treatment system. DRMS sent Cotter a September 9, <br />2011 letter regarding Cotter's notification, which requests a "technical assessment as to the <br />probable source of elevated uranium" in this area, referred to as the area of Sump No. 10 by <br />DRMS. At the request of Cotter, AMEC Earth & Environmental (AMEC) has conducted this <br />technical geochemical assessment as to the probable source of elevated uranium in Sump No. <br />10. <br />2.0 GEOCHEMICAL EVALUATION <br />The chemistry of water collected in Sump No. 10 was evaluated with respect to potential <br />sources of uranium and total dissolved solids (TDS), by comparing various water quality <br />parameters and geochemical signatures from potential proximal sources to those observed in <br />Sump No. 10. Recent (2011) groundwater monitoring data supplied by Cotter for selected <br />upgradient (MW -0, MW -1, Sump No. 9) and downgradient (MW -3A, Sump No. 4, MW -9, Sump <br />No. 5, and MW -6) alluvial groundwater monitoring locations were used for the analysis (Figure <br />1, Table 1). <br />2.1 Major Ion Chemistry <br />Sump No. 10 water contains elevated concentrations of calcium, magnesium, sodium, sulfate, <br />and consequently TDS, compared to other upgradient and downgradient alluvial groundwater <br />(Table 1). The recent concentrations of several major ions and TDS in water collected at Sump <br />No. 10 were compared to those of the mine pool and to both upgradient and downgradient <br />alluvial groundwater. The results on Figure 2 show that the mine pool water contains the highest <br />AMEC Environment & Infrastructure <br />118 E. 29 Street, Suite C <br />Loveland, Colorado 80538 <br />Tel (303) 630 -0788 <br />Fax (970) 669 -0003 <br />