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Evans Mining Resource <br /> Groundwater Monitoring Plan <br /> October 2024 <br /> Page 6 <br /> 4.2.4 Groundwater Point of Compliance Wells <br /> Down-gradient wells MW-4, MW-5, and MW-6 will serve as the designated "Points of <br /> Compliance"(POC)wells in accordance with Rule 3.1.7(6)(b)(ii)(A). <br /> 4.2.5 Groundwater Quality Data Evaluation and Trigger Levels <br /> ASCI will compare laboratory results against the site-specific groundwater quality benchmarks <br /> developed for the Site to determine if any exceedance(s) of the benchmarks has occurred. The <br /> primary trigger for evaluating if potentially adverse impacts to groundwater have occurred will be <br /> if results for any analytes exceed their baseline groundwater quality benchmark in the POC <br /> monitoring wells MW-4, MW-5, and/or MW-6. <br /> 4.2.6 Reporting <br /> Unless exceedances above baseline groundwater quality benchmarks occur in POC wells(MW-4, <br /> MW-5, and MW-6), ASCI will report groundwater quality monitoring results to DRMS as <br /> supplemental information with the annual report for the Site each year. If analyte exceedance(s) <br /> of site-specific groundwater quality benchmarks are reported in up-gradient monitoring wells <br /> (MW-1 and MW-3), this would indicate the impact to groundwater quality is potentially from an <br /> off-site source. Should analyte exceedance(s) occur in up-gradient wells only, ASCI will monitor <br /> results from subsequent groundwater sampling events to determine if elevated concentration(s)of <br /> the analyte(s) persist. If exceedance(s) of baseline groundwater quality benchmarks are detected <br /> in down-gradient POC wells (MW-4, MW-5, and MW-6), ASCI will contact DRMS upon <br /> discovery to discuss the path forward. Subsequent actions may potentially include: <br /> • Conduct confirmation sampling of well(s) for the exceeding parameter(s). <br /> • Evaluate the existing data set to determine if any trends are present. <br /> • Increase groundwater sampling event frequency to determine if impacts are anomalous <br /> and/or temporary, as applicable. Install additional up-gradient and/or down-gradient POC <br /> wells, as necessary, if exceedances persist. <br /> • If exceedances persist, conduct a statistical trend analysis to determine: 1) if exceedances <br /> are statistically significant increases over background; and/or 2) if a new site-specific <br /> groundwater quality benchmark is appropriate (to be submitted to DRMS as a Technical <br /> Revision). <br /> ASCI will work with DRMS to address impacts identified in POC wells, as appropriate, based <br /> upon the situation encountered at that time. <br />