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MALCOL <br />PIRNIIM <br />ARCAD1S <br />The Water Division of ARCAD1S <br />Date:. January 25, 2011 �• <br />To: Daniel Arnold, Esq., Denver Water <br />Copy: Jason Kerstiens, Malcolm Pirnie <br />From: Tim Cox, P.G. CGWP, Jeff Gillow, PhD., and Phil <br />DeDycker, P.E. ARCADIS <br />Re: Review of Schwartzwalder Mine Environmental Protection <br />Plan <br />1.0 INTRODUCTION <br />Technical Memorandum <br />Denver Water retained ARCADIS U.S., Inc. /Malcolm Pirnie, Inc. to review and <br />comment on the Environmental Protection Plan (EPP) for the Schwartzwalder Mine <br />(mine), which is located approximately 4 miles northwest of Golden, Colorado in <br />Jefferson County. The uranium deposit was discovered by Fred Schwartzwalder in 1949. <br />Exploration and uranium mining progressed slowly and increased in 1953 with assistance <br />from the Federal government. The mine was sold to Denver - Golden Oil and Uranium <br />Company in 1956. Cotter Corporation (N.S.L.) (Cotter) purchased the mine in 1966 and <br />operated the mine through 2000 after which operations ceased and the underground mine <br />was allowed to flood. The Colorado Division of Reclamation, Mining and Safety <br />(DRMS) identified the mine as a Designated Mining Operation because toxic materials <br />have been exposed or disturbed as a result of mining, and required Cotter to submit an <br />EPP in accordance with the Colorado Mine Land Reclamation Act and the Hard Rock <br />/Metal Mining Rules and Regulations. The intent of the EPP is to provide information for <br />improvements in the protection of human health, property, and the environment related to <br />affected areas of the mine including reclaimed waste rock piles, the flooded underground <br />workings, and valley fill. The EPP also evaluates potential mitigation measures to address <br />these affected areas and to protect the water quality of Ralston Creek. <br />As directed by Denver Water, the objectives of this EPP review are to: 1) identify major <br />findings, 2) assess the analyses performed and data adequacy that support the findings, 3) <br />provide interpretations as appropriate, and 4) assess the proposed mitigation options. An <br />additional task is to review comments prepared by DRMS on the EPP. This Technical <br />Memorandum summarizes the results of the EPP review and includes the following <br />sections: <br />• Section 1: Introduction <br />e Section 2: Summary of Key EPP Review Conclusions <br />• Section 3: Review of EPP <br />o 3.1 Waste Rock Piles <br />o 3.2 Valley Fill Material <br />o 3.3 Alluvial Groundwater <br />4-1177- 3o0 <br />A-At -a <br />