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Permit #: - - Confidental?: <br />Class: Type-Seq.: CIVIL R E SOU R C E S, L L C <br />From: LC~Q T°i ~ [NQ NEF_RS & PLANNLRS <br />Doc. Name: <br />Doc. Date (if no date stamp): 7_ _____ <br />June 25, 2007 <br />Mr. Tom Schreiner <br />Division of Reclamation and Mining Safety ~~~N 282007 <br />1313 Sherman Street, Room 215 Dmsron otReaamation, <br />Denver, Colorado 80203 Mining and Safety <br />RE: April 2007 Groundwater Quality Monitoring Results, Lupton Lakes Gravel Mine <br />Permit No. M•2004.078 <br />Dear Mr. Schreiner: <br />The following letter report describes the results from the April 2007 Sampling Event. This report is being <br />submitted in general compliance with approved Groundwater Sampling and Analysis Plan (GWSAP) included <br />in Technical Revision 2 (TR2) to the Lupton Lakes Gravel Pennit issued by the State of Colorado Division of <br />Minerals and Geology. <br />Monitoring wells CRMW01, CRMW02, CRMW04, CRMWO6, CRMW09, CRMW16, and CRMW41 were <br />redeveloped prior to the sampling events to reduce the amount of sediment in these wells. There was no <br />dewatering of the mine at the time of this sampling event. <br />Groundwater Monitoring Results <br />The April 2007 Sampling Event includes monitoring wells CRMW 01, CRMW02, CRMW04, CRMWO6, <br />CRMW09, CRMW16, and CRMW41. Following is a listing of the major results and conclusions: <br />• Arsenic concentrations did not exceed the proposed baseline level for this site of 0.03 mglL. <br />Fecal Coliform was detected in three wells (CRMW01, CRMW04, and CRMWO6) at a level of 2 <br />mpn/100m1 in each well. The PDWS standard for fecal colifomt is no detection. Fecal Coliform was <br />not detected in any of the other wells tested in this sampling event. The proposed baseline level for <br />fecal coliform concentration level is 1. Each of these exceedances occurzed in wells located <br />downgradient or cross gradient from inhabited structures with active septic systems. <br />Fluoride did not exceed the PDWS or the proposed baseline levels in all wells tested. <br />• Mercury concentrations did not exceed the Primary Drinking Water Standards (PDWS), however the <br />mercury concentration in CRMW04 exceeded the proposed baseline levels by 0.00007 mg/L. <br />• Nitrate (as N) exceeded PDWS in five of the seven wells sampled with nitrate concentration levels <br />ranging from less than 0.04 up to 43.08 mg/L in CRMW02. The PDWS for nitrate is 10 mglL. The <br />proposed site wide baseline level for nitrate is 29.9 mg/L. Two of the five wells that exceeded the <br />PDWS standard also exceeded the proposed baseline level for Nitrate including: CRMW02 (43.08 <br />mg/L) and CRMW41 (31.34 mg/L). However, considedng the very limited mining activity that had <br />been completed at the date of this sampling event in the vicinity and upgradient of these wells and <br />the fact that these wells are located at the north side of the site (1 mile away from the mining area), <br />these exceedances are not attributable to mine activity and should be considered in reevaluating <br />approved baseline levels in the area. <br />323 F,FTri STREET • P. O. Box 6B0 FRE~ERIGK, CO HO53^ PHONE (3031 833-7 41 6 • Fnx 1303) 833-2050 <br />