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71 West, 6`'' Principal Meridian, in Jefferson County, Colorado. The site is adjacent to <br />Ralston Creek, a perennial stream that flows into Ralston Reservoir 1.6 miles downstream of <br />the property boundary. Ralston Reservoir supplies drinking water to Denver and Arvada. <br />The site is located in a valley and some of the mine's underground workings are in the <br />hillside above the level of Ralston Creek. <br />2. Uranium mining at the site began in 1953. The Operator purchased the site in <br />1966. The Operator ceased uranium production at the site in 2000. <br />3. The site has seven acres of alluvium and fill, known as the alluvial fill area. <br />The alluvial fill area is in the valley adjacent to Ralston Creek. Ralston Creek was diverted <br />toward the north side of the canyon to make room for mine buildings and facilities <br />constructed upon the alluvial fill. The alluvial fill is partially composed of mine waste rock. <br />The mine related buildings have been removed, except for the water treatment plant. The fill <br />remains. April 16, 2010 Technical Memorandum from Whetstone Associates to the Division <br />("April 16 Memo"). The fill contains uranium, molybdenum, and other metals due to the <br />mine waste rock. The alluvial fill is in direct hydraulic contact with Ralston Creek. <br />4. The Operator maintained a water treatment system at the site from 1972 to <br />June, 2002. The water treatment system is permitted by the Colorado Department of Public <br />Health and Environment ("CDPHE") under CDPS number CO-0001-244. The Operator has <br />other permits issued by the CDPHE for air quality, storm water discharge, and radioactive <br />materials processing. <br />5. The Operator shut down the water treatment system in June 2002 after <br />receiving permission from the CDPHE, and per the permit specifications. <br />6. In April 2008, sump recirculation at the site ceased. Subsequent semiannual <br />monitoring and effluent report data show increased levels of uranium in the Ralston Creek <br />monitoring station, BPL, located at the edge of the affected area and down stream from <br />where Ralston Creek flows past the alluvial fill. The levels of uranium in Ralston Creek <br />have exceeded regulatory limits since water treatment and then the sump recirculation <br />ceased. <br />7. For example, in December 2009 Ralston Creek showed a 400 times increase in <br />uranium concentration from upstream of the mine (0.0012 mg/L; from SW-AWD, December <br />2009) to downstream (0.468 mg/L; December 2009, SW-BPL). April 19, 2010 <br />Environmental Protection Plan ("EPP") at Table 11-7, p. 11-16. <br />8. In late June 2007, the Division inspected the site and learned that the mine <br />pool contained 44 mg/L uranium and was 34 feet below the Steve Level adit and rising. <br />9. In 2008 the Division began receiving water quality monitoring reports from <br />the CDPHE Radiation Program. <br />10. In July 2009, the Division advised the Operator that "water quality degradation <br />at the mine is critical and may be approaching conditions requiring emergency response <br />under §34-32-124.5 C.R.S." <br />Cotter Corp. <br />Schwartzwalder Mine 2 <br />M-1977-300 <br />MW-2010-018