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n <br />LJ <br />1.0 INTRODUCTION <br />• The following report describes the results from the October 2008 Sampling Event and analyzes the results of the sampling <br />events over the past year. Dewatering began in the area of the south sediment pond near Weld County Road 6 % in June <br />2007 and stopped in May of 2008. Dewatering began in the area of the north silt pond in April 2008. The groundwater was <br />• pumped into an infiltration gallery located near the northeast corner of the project until a sixteen (16) inch high density <br />polyethylene (HDPE) pipe was installed under Hwy 85. The sediment in the water was allowed to settle out then it was <br />discharged through the HDPE pipe into the South Platte River. Discharge into the South Platte River began in May 2008. <br />• There was no mine dewatering or discharge observed during the October 2008 sampling event. Future discharges from mine <br />dewatering will be into the South Platte River and no groundwater recharge is anticipated. The National Pollution Discharge <br />Elimination System Permit (NPDES) and any associated water sampling is and has been the responsibility of Lafarge. <br />• 2.0 OCTOBER GROUNDWATER MONITORING RESULTS <br />The October 2008 Sampling Event included monitoring wells (CRMW) 01, 04, 05, 06, 09, 16, 40, 41, and 42. The mining <br />• conveyor system was placed over the top of well CRMW02 between the January and April 2008 sampling events making this <br />well inaccessible. The results of the October monitoring event are generally consistent with previous events as summarized <br />below. <br />• <br />• <br />2.1 Primary Drinkin_a Water Standards <br />Sampling results from October 2008 show that the Primary Drinking Water Standards (PDWS) were exceeded for nitrates, <br />and fecal coliform. Following is a general description and discussion of results related to PDWS analytes: <br />• Nitrate (as N) exceeded PDWS in five of the nine wells sampled across the site ranging from 0.6 up to 30.4 <br />milligrams per liter (mg/L). The site wide nitrate baseline level was not exceeded. <br />• Fecal coliform exceeded PDWS in three of the four wells sampled across the site ranging from undetected up to 9 <br />most probable number per 100 milliliters (mpn/100ml). Fecal Coliform was detected in wells CRMW01, CRMW09 <br />and CRMW41 in the October 2008 sampling event. The test detection limit is 2 mpn/100ml with a site wide baseline <br />level of 1 mpn/100ml. Several septic systems are located within the area from single family homes and from a larger <br />modular home park. <br />• Fluoride did not exceed the PDWS standard level of 4 mg/l, but did exceed the baseline level in CRMW06 during <br />April 2008, CRMW16 during January 2008 and CRMW41 during July and October 2008. <br />• Mercury was not detected in the four wells sampled in October 2008. <br />• Dissolved arsenic did not exceed the PDWS or the baseline levels in October 2008. <br />2.2 Secondary Drinkina Water Standards <br />Sampling results from October 2008 show that the Secondary Drinking Water Standards (SDWS) were not exceeded for any <br />analytes. Following is a general description and discussion of results related to SDWS analytes: <br />• The chloride concentrations were below baseline and SDWS levels in October 2008. <br />• The sulfate concentrations did not exceed SDWS or baseline levels in October 2008. <br />• Total dissolved solid concentrations did not exceed SDWS or baseline levels in October 2008. <br />Annual 2008 Sampling Report - Lupton Lakes <br />-1- <br />December 2008