2022-11-03_PERMIT FILE - M2021067

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Stiles Mining Resource Groundwater Monitoring and Mitigation Plan November 2022 Page 2 Monitoring wells were installed to a depth slightly above the top of bedrock encountered. Monitoring wells are constructed of two (2)-inch diameter Schedule 40 PVC with factory slotted 0.010" slot size for the screened portions. The filter packs consist of 10/20 silica sand and extend approximately two (2)-feet above the top of the well screen. A bentonite seal (chips)was installed from the top of the filter pack to ground surface. At the surface, a two (2)-foot x two (2)-foot concrete pad was installed around each well along with a four(4)-inch square steel well cover with hinged locking cap to protect the above ground riser. Copies of the monitoring well construction logs are provided in Appendix A. Three (3) of the monitoring wells (MW-1, MW-2, and MW-3) are located hydraulically up- gradient along the western and southern boundaries of the property owned by Hunt Brothers Properties (HBP)which includes proposed mining operation. Three(3)monitoring wells (MW-4, MW-5, and MW-6) are located hydraulically down-gradient along the northern and eastern boundaries of the HBP property. The down-gradient wells (MW-4 through MW-6) will serve as the designated "Points of Compliance" (POC) wells in accordance with Rule 3.1.7(6)(b)(ii)(A). The location of the monitoring wells are shown on Figure 2. 3.2 GROUNDWATER SAMPLING EVENT FREQUENCY AND SCHEDULE ASCI will conduct five(5)consecutive quarters of groundwater sampling to document background groundwater quality conditions at the Site prior to commencing mining operations (Pre- Operational Background Sampling). After mining operations begin, ASCI will conduct quarterly monitoring (i.e., current groundwater quality monitoring schedule) for a minimum of four (4) consecutive quarters(Post-Operational Sampling).Any change to the current groundwater quality monitoring schedule (i.e., reduction in sampling frequency) will be submitted to DRMS via Technical Revision for approval prior to implementing. The following table outlines the anticipated groundwater quality schedule through four(4) quarters of post-operational sampling. Time Period Activities Conducted 2022 1 st Quarter Correspondence with DRMS on groundwater quality requirements (e.g., (January- March) parameters,frequency, etc.)and agreement for monitoring well locations. Installation of Monitoring Wells Conduct 1 st Quarter Pre-Operational Background Groundwater Sampling Event 2nd Quarter Conduct 2nd Quarter Pre-Operational Background Groundwater Sampling Event (April- June) 3rd Quarter Conduct 3rd Quarter Pre-Operational Background Groundwater Sampling Event (July- September) 4th Quarter Conduct 4th Quarter Pre-Operational Background Groundwater Sampling Event (October-December)