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Mr. David Berry <br />May 14, 2010 <br />Page 2 <br />Fortunately, the drinking water being produced at the Moffat Treatment Plant does not <br />contain elevated levels of radionuclides - it appears that treatment processes are currently <br />removing the contamination. However, the Moffat Treatment Plant was not designed to remove <br />uranium, molybdenum, or other metals - any removal is incidental. Therefore, it is uncertain <br />how an increase in uranium, a steady supply of uranium, or an accumulation of uranium within <br />the reservoir could affect treatment capabilities at the plant. Denver Water may need to make <br />modifications to the plant to permanently address this problem. Such modifications may require <br />new treatment processes or upgrades that are not currently included in future plans for plant <br />modification. The cost and implementation schedule of such modifications are unknown. The <br />financial impact to Denver Water customers could be enormous, and a violation of the safe <br />drinking water act standard for uranium could adversely affect the state's economy. It seems <br />reasonable that these costs should be borne by Cotter. <br />In addition to impacts to the Moffat Plant's treatment system, Denver Water would also <br />have to mitigate increased levels of uranium and radium in the plant's sludge, which contains <br />sediment removed from the water. The sludge from the Moffat Treatment Plant currently meets <br />the requirements for beneficial reuse as a bulking agent in compost materials; it is currently used <br />by a local vendor in this manner. As radioactive-constituent levels increase, Denver Water may <br />be forced to find a different disposal method for the sludge and provide protections to employees <br />managing the sludge, incurring much greater costs. <br />The impacts of increasing uranium concentrations in Ralston Creek, recently more than <br />17 times the drinking water standard for uranium, are of significant concern to Denver Water <br />because of the potential health risk to customers (one quarter of the state's population), the <br />impact to the environment, and the cost of additional treatment that customers will incur if Cotter <br />does not complete reclamation of the Schwartzwalder Mine site in a responsible manner. <br />Therefore, Denver Water asks that the Division of Reclamation partner with the Colorado <br />Department of Public Health and Environment to take immediate and aggressive steps to ensure <br />that reclamation of the mine is completed in a timely manner. <br />Specific Comments on Cotter's EPP <br />Cotter's EPP suggests that there are at least four potential sources of uranium entering <br />Ralston Creek: water from the mine, the rock pile immediately adjacent to Ralston Creek, the <br />Schwartz Trend as it intersects Ralston Creek, and the alluvial fill material under the site of the <br />mine's old buildings. Three of these sources were created as a direct result of mine operations <br />and need specific mitigation measures to ensure uranium and other metal concentrations are <br />lowered in Ralston Creek. <br />Mine Water: The EPP makes an effort to discount the potential impact of contaminated <br />water in the mine on Ralston Creek. Yet the report is clear that several constituents in <br />mine water samples, including antimony, arsenic, molybdenum, thallium, uranium, and <br />radium 226, tested above Colorado groundwater standards. Four of these constituents are