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DENVER WATER <br />1600 West 121h Avenue • Denver, Colorado 80204-3412 <br />Phone :303-628.6000 • Fax No. 303-628.6199 • denvenvater.org <br />May 14, 2010 <br />Mr. David Berry <br />Office of Active and Inactive Mines <br />Division of Reclamation, Mining and Safety <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />Re: Comments on Schwartmalder Mine Environmental Protection Plan <br />Dear Mr. Berry: <br />The City and County of Denver, acting by and through its Board of Water <br />Commissioners ("Denver Water") submits the following comments for your consideration with <br />regard to the Environmental Protection Plan (EPP) submitted by the Cotter Corporation <br />("Cotter") for its Schwartzwalder Mine, dated April 16, 2010. <br />Denver Water owns and operates Ralston Reservoir on Ralston Creek, downstream from <br />the Schwartzwalder Mine. Ralston Reservoir provides a direct, piped feed to the Moffat Water <br />Treatment Plant, and is one of the primary water sources for Denver Water and its 1.3 million <br />customers. Ralston Reservoir is also the location from which raw-water deliveries to the City of <br />Arvada and North Table Mountain Water and Sanitation District are made. <br />Denver Water data shows that uranium concentrations in Ralston Creek (at the Long <br />Lake Headgate) were fairly stable, though still above the drinking water limit, at 80-100 µg/L <br />until October 2008. This date seems to correspond to the general timeframe when Sump 1 was <br />turned off at the Schwartzwalder Mine and the water level in the mine reached "steady state." <br />Since October 2008, uranium concentrations in Ralston Creek entering Ralston Reservoir have <br />risen steadily to over 500 pg/L. <br />Though Cotter's EPP argues that the interaction between groundwater and surface water <br />in the vicinity of Schwartzwalder Mine is not yet precisely defined, monitoring of Ralston Creek <br />at Long Lake Head Gate and the raw water received at the Moffat Treatment Plant clearly show <br />increased radionuclide concentrations over the course of Cotter's reclamation activities (see <br />attachments). In addition, Cotter's EPP provides documentation that the uranium concentration <br />in Ralston Creek upstream of the Schwartzwalder mine is only 4 gg/L. This data strongly <br />suggests that the interaction and the dispersal of contaminants from groundwater to surface water <br />in the vicinity of the mine cannot be denied. Denver Water can only conclude that reclamation <br />of the Schwartzwalder Mine is far from complete and must be modified to stem the release of <br />contaminants in order to protect public health and the environment. <br />CONSERVE