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Denver Water Comments Re: Schwartzwalder <br />With regard to the interim treatment method selected by Cotter, the method appears to be <br />a zeolite-based form of ion-exchange without regeneration of the media. Media with <br />accumulated uranium will be disposed of presumably off-site. The media is selective for <br />uranium and will not remove radium. Gross Alpha reduction will only occur for the proportion <br />of Gross Alpha that can be associated with uranium. The method used by Cotter should also be <br />capable of removing Gross Alpha. Also, the interim treatment rate appears to be 40 gpm based <br />upon the equipment immediately available and not necessarily the flow rate needed to control the <br />fate and transport of contaminants. Why is 100 gpm the correct rate for final treatment? There <br />appears to be no rationale for why 100 gpm is the correct rate. Additionally, the prehearing <br />submittals do not contain any rationale to support Cotter's position that final treatment is only <br />necessary through 2012. Why is only two years of treatment necessary when there is uncertainty <br />regarding leakage from the mine pool? <br />In terms of Cotter's financial surety, the MLRB should consider a higher bond <br />requirement for this reclamation, particularly considering that the reclamation project's <br />proximity to a critical drinking water reservoir serving drinking water to a quarter of the <br />population in Colorado. A significantly higher bond is justifiable for a bulkhead-type solution <br />where there is a limited track record of use or success and until zero leakage from the mine pool <br />is proven. In addition, because of the potential threat posed to Denver Water and other water <br />utilities in the area, the MLRB should consider requiring that Cotter provide an additional <br />financial surety to Denver Water and other third parties who potentially face significant costs as <br />a consequence of the conditions created by the Schwartzwalder Mine. Finally, Cotter is <br />requesting relief from a bond for interim treatment claiming that equipment is already purchased. <br />A bond should be required and released only upon successful operation of the more permanent <br />treatment solution. <br />In general, Denver Water believes that allowing masses of geochemically unstable <br />radionuclides to accumulate within close proximity to drinking water reservoirs presents a threat <br />to public health and raises serious public policy concerns. Denver Water commends DRMS for <br />the actions it has taken so far, and encourages the MLRB to closely assess the risks posed by the <br />conditions at the Schwartzwalder Mine. <br />Sincerely, <br /> <br />Thomas Mountfort <br />Environmental Compliance Supervisor <br />Denver Water <br />cc: Steve Gunderson <br />Charlotte L. Neitzel <br />Loretta Pineda <br />David Berry <br />David Bird <br />Page 2 of 2