2024-11-04_PERMIT FILE - M2024056 (6)

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Evans Mining Resource Groundwater Monitoring Plan October 2024 Page 4 4.0 GROUNDWATER MONITORING PLAN The following activities will be conducted to monitor groundwater quantity and quality throughout the operational life of the mine until reclamation is complete. Any changes to the information presented in this GWMP because of additional baseline characterization data collected will be provided to the DRMS in the Baseline Data Summary Report. 4.1 GROUNDWATER QUANTITY 4.1.1 Groundwater Measurement Schedule ASCI will continue to collect and evaluate monthly groundwater elevation readings from Site monitoring wells for a minimum of 12 months after mining operations have commenced to monitor for adverse impacts to the hydrologic balance. Any change to the groundwater level monitoring schedule (i.e., reduction in measurement frequency) will be submitted to DRMS via TR for approval prior to implementation. 4.1.2 Groundwater Quantity Data Evaluation and Trigger Levels The primary trigger for evaluating if potentially adverse impacts to the hydrologic balance exist will be if a persistent change groundwater levels in Site monitoring wells either increases two (2) feet above the baseline high measurement or decreases two (2) feet below the baseline low measurement. The current trigger measurements for each well are provided in the following table. Baseline GW Trigger Elevation Baseline GW Trigger Elevation Well ID Elevation—High for Evaluating Elevation—Low for Evaluating High GW Impacts Low GW Impacts MW-1 4667.91 4669.91 4662.84 4660.84 MW-2 4666.43 4668.43 4661.21 4659.21 MW-3 4664.09 4666.09 4660.08 4658.08 MW-4 4664.71 4666.71 4659.43 4657.43 MW-5 4662.22 4664.22 4657.63 4655.63 MW-6 4661.30 4663.30 4657.28 4655.28 MW-7 4662.63 4664.63 4658.43 4658.43 Notes: Elevations in feet above mean sea level(ft amsl) 4.1.3 Reporting Groundwater levels collected will be compared against the final baseline data set. Unless groundwater evaluation trigger levels are exceeded, ASCI will report groundwater level data to DRMS as supplemental information with the annual report for the Site each year. Should high or low groundwater evaluation trigger levels be exceeded,ASCI will contact DRMS upon discovery to discuss the path forward. Subsequent actions may potentially include continued/increased monitoring frequency, conduct a groundwater mounding/shadowing evaluation, etc.