Laserfiche WebLink
CDPS EXCEEDANCE REPORT <br />Mine Site: COLOWYO MINE <br />Outfall No.: 004A <br />Sample Taken by: Env. EnQ. -Tonv Tennyson <br />Permit No.: CO-00045161 <br />Sample Date: 02/13/2007 <br />Laboratory Sample ID: S0610332-005 <br />Exceedences: Total Susuended Solids - 76 m¢/L Report Prepared by: Tonv Tennvson <br />Total Recoverable Iron - 7.34 mQ1L <br />Explanation: <br />Precipitation records indicate that a rainfall event occurred at Colowyo the two days prior to the <br />February 13, 2007 sampling date. Temperatures on the two prior stated dates reached highs of 41.4°F <br />and 35.3°F respectively. The sample was taken on February 13, 2007 and rainfall and snow melting <br />events were observed on this date. The storm patterns on the days prior to the February 13, 2007 <br />sample suggest short duration high intensity rainfall events (thunderstorms) which caused multiple <br />flows from surface runoff and snow melt (from temperature and precipitation) caused multiple <br />inflows into the pond from the surrounding designed ditches. Discharge from the pond began as a <br />result of the series of storms that passed through the area two days prior and elevated temperatures <br />prior to sampling. Precipitation was measured on the February 11 and 12, 2007, and sampling was <br />performed at 10:50 AM on February 13, 2007, thus qualifying for consideration of the use of <br />Alternative Effluent Criteria for this sample. <br />Identify Support Info: <br />Relevant laboratory data from Outfall 004A <br />Proposed Action: <br />Flocculation chemicals approved in the CDPS permit will be added to the pond waters in order to <br />reduce the TSS concentration of the waters that could potentially be discharged from the pond to <br />below the MCL of 35 mg/L in the future. Colowyo is also working with representatives from GE <br />Betz to identify flocculation chemicals and treatment options in order to prevent future TSS MCL <br />exceedences. <br />Stormwater avenues into the pond are being re-evaluated and will be modified as necessary to <br />minimize sedimentation caused by runoff originating from disturbed areas. <br />Sediment cleanout of this pond was completed during November 2006. <br />Name• <br />Date of Submitta : Z 7 0 <br />N:\CCC_HSEQ\21.0 WQCD\21.1 CDPS Permi[\21.1.2 Inspections & Reports\2007\CDPS Exceedance Report_004A-1'st QTR.doc <br />