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The initial sampling will purge six(6)well volumes of water prior to sampling to remove residue left over from <br /> the drilling process. Subsequent sampling events will require three(3)volumes of water purged prior to <br /> sampling. Field parameters of pH,temperature,conductivity,and dissolved oxygen will be sampled before and <br /> after each volume of water inside the well is purged. The meter for sampling field parameters will be cleaned <br /> and calibrated prior to use. If field parameters vary more than 10%between purges,then purging should <br /> continue until six(6)volumes have been purged.The static volume of water in the well will be calculated using <br /> the following equation: <br /> V=r2h(0.163) <br /> Where <br /> V=static volume of water in well(in gallons) <br /> r=inner radius of well casing (in inches) <br /> h=length of water column (in feet)which is equal to the total well <br /> depth minus depth to water. <br /> 0.163=a constant conversion factor that compensates for the <br /> conversion of the casing radius from inches to feet for 2-inch diameter <br /> wells and the conversion of cubic feet to gallons, and pi(A).This <br /> factor would change for different diameter wells. <br /> Samples will be collected in a matter described by the laboratory and in the bottles they provide. The <br /> Groundwater will be retrieved using disposable polyethylene bailers and poured into a clean pitcher to be <br /> distributed to the appropriate sample bottle. Samples will be stored inside a cooler packed with ice and will be <br /> delivered to the laboratory within twenty-four(24)hours. <br /> A chain of custody form will be completed indicating the analysis to be performed on each sample and will <br /> accompany the samples to the lab. <br /> 5.2 Analytes To Be Sampled <br /> MMMA will sample the analytes listed in Appendix B of the"Groundwater Monitoring: Sampling and Analysis <br /> Plan Guidance"September 2023. The full list of analytes is shown in Appendix B. <br /> 5.3 Report and Release <br /> The analytical results will be reviewed and a summary compiled comparing the results to the regulatory limits <br /> established by the Colorado Water Quality Control Commission (WQCC)and listed in Tables 1-4 of Regulation <br /> 41. After the end of the five(5)quarters of baseline monitoring, MMMA will submit a report to the Division <br /> discussing the results. If any analytes exceed the reference values listed in Regulation 41 Tables 1-4,then <br /> MMMA will request a variance for that specific analyte and propose a numerical reference value for the Site. <br /> MMMA will sample the three(3)wells after final reclamation and provide the results in a report to the DRMS to <br /> determine whether or not the Site had a negative effect on groundwater quality. <br /> 6.0 GROUNDWATER ELEVATION MONITORING AND MITIGATION <br /> This section supplements the Groundwater Model Report which recommends an underdrain mitigation structure south of <br /> Cell 3 and is described in the Groundwater Model Report. For more detail on the proposed underdrain, see the <br /> recommendations section of the Groundwater Model Report. <br /> The Site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater elevation <br /> associated with mining and reclamation activities. Baseline data collected from the monitoring program will provide a <br /> range and measure of variability of relative water levels associated with pre-mining groundwater conditions. Experience <br /> Monitoring and Analysis Plan—Monarch DENM Gravel Mine -4- March 2024 <br />