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Chavers Mining Resource <br /> Groundwater Monitoring and Mitigation Plan <br /> January 2024 <br /> Page 6 <br /> each other for all stabilization parameters) and/or a minimum of three (3) well volumes are <br /> removed, groundwater will be collected directly into laboratory-supplied containers with the <br /> preservative appropriate for the analysis requested, as applicable. The samples will be labeled, <br /> placed in a cooler with ice(cooled to 4°C),and stored until delivery to the laboratory accompanied <br /> by chain-of-custody documentation. <br /> 3.2.3 Laboratory Analysis of Groundwater Samples <br /> Groundwater samples submitted to the laboratory will be analyzed for thirty (30) applicable <br /> WQCC Regulation 41 INS Tables 1 -4 analytes.The following analytical methods(or comparable <br /> methods)will be utilized by the laboratory to report water quality results. <br /> ■ Nineteen (19) Metals (Dissolved)by EPA Method 200.8 <br /> ■ Two (2) Metals (Dissolved) by EPA Method 200.7 <br /> ■ Six(6) Inorganic Anions by EPA Method 300.0 + Calculation <br /> ■ Chromium by Standard Method(SM) 3500-Cr B + Calculation <br /> ■ pH by SM 4500-H-B <br /> ■ TDS by SM 2540-C <br /> 3.2.4 Groundwater Quality Data Evaluation and Trigger Levels <br /> ASCI will compare laboratory results against the groundwater quality standards developed for the <br /> Site(Table 2)within one(1)week of receipt to determine if any exceedance(s)of the groundwater <br /> quality standards has occurred. The primary trigger for evaluating if potentially adverse impacts <br /> to groundwater have occurred will be if results for any analytes exceed their site-specific <br /> groundwater quality standard. <br /> 3.2.5 Evaluating Impacts to Groundwater Quality and Mitigation Measures <br /> If analyte exceedance(s)of site-specific groundwater quality standards are reported in up-gradient <br /> monitoring wells (MW-2 through MW-3), this would indicate the impact to groundwater quality <br /> is potentially from an off-site source. Should analyte exceedance(s) occur in up-gradient wells <br /> only, ASCI will monitor results from subsequent groundwater monitoring sampling events to <br /> determine if elevated concentration(s)of the analyte(s)persist and/or if migration to down-gradient <br /> POC wells (MW-4 through MW-6) occurs. If exceedance(s) of site-specific groundwater quality <br /> standards occur in POC wells (MW-4 through MW-6), ASCI will contact DRMS within five (5) <br /> days of discovery to discuss the path forward. Potential mitigation measures may include: <br /> ■ Conduct confirmation sampling of well(s)to verify results. <br /> ■ Evaluate the existing data set to determine if any trends are present in up-gradient and <br /> down-gradient wells. <br /> ■ Increase groundwater sampling event frequency to determine if impacts are anomalous <br /> and/or temporary (e.g., sample quarterly until two [2] consecutive quarters of monitoring <br />