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W W RESOURCE <br /> `/ HYDROGEOLOGIC <br /> SERVICES <br /> well installation program, the required CDWR Well Construction and Yield Estimate Reports (GWS-31 <br /> forms) shall be submitted by RHS to CDWR within 60 days of completion of each monitoring well, per <br /> CDWR regulations. <br /> MONITORING WELL LOCATIONS <br /> Phase II monitoring locations have been selected for three areas as shown in Figure 1. MW-9 and MW- <br /> 10 are upgradient(presumed at this point based on formation dip)of the existing and planned mine panels <br /> to allow baseline groundwater condition monitoring, MW-11 and MW-12 immediately downgradient of <br /> mine panels 3 and 4, and MW-13, MW-14, and MW-15 (potential) downgradient of all mine panels and <br /> the plant, in the northeast portion of the mine permit area. The latter location is currently considered the <br /> point-of-compliance location,again based on formation dip direction, until these Phase II monitoring wells <br /> are installed allowing determination of groundwater flow direction. <br /> Each new monitoring location shall consist of two wells completed in the two intervals of interest in a <br /> tightly spaced straight line "twinned" configuration with surface spacing distance on the order of 20 feet. <br /> In the case that a third well is necessary at the planned presumed downgradient point-of-compliance <br /> location (see Borehole Drilling& Monitoring Well Installation Colluvium section below),the configuration <br /> will be the three wells in a line each separated by approximately 20 feet surface spacing. The orientation <br /> shall be at a bearing of approximately 45' in line with formation dip direction with the shallowest well to <br /> the southwest (upgradient) and deepest well to the northwest (downgradient). <br /> Locations shall be surveyed by the GCC-contracted professional surveyor in advance of mobilization of the <br /> drilling and completion effort.This process will be part of the underground utility clearance, but will also <br /> confirm all planned monitoring well locations are inside of the DRMS mine permit boundary and, in the <br /> case of the presumed upgradient monitoring well location, outside of the southwest extent of the mine <br /> panels 3 and 4. GCC shall commit to a minimum 300-foot mining setback from this location to prevent <br /> future disturbance to monitoring. A follow-up survey of the as-built monitoring wells shall also be <br /> conducted, with emphasis on high accuracy elevation in order to allow future reliable plotting of the <br /> potentiometric groundwater elevation data across the facility, thus allowing determination of <br /> groundwater gradient and flow direction. <br /> MONITORING WELL DESIGN <br /> Specifications for the monitoring well designs are included in this Work Plan as Table 1. This design follows <br /> industry standard practice and is intended to be installation guidance, but the as-built construction will <br /> be ultimately determined by the professional judgement of the RHS field hydrogeologist based on site- <br /> specific conditions. Well design shall be industry standard 2-inch PVC monitoring wells installed for the <br /> purpose of monitoring groundwater level and water quality of the specified intervals identified during <br /> drilling and subsurface documentation at the planned monitoring well locations. Figure 1 shows the <br /> GCC Rio GRANDE,INC.PUEBLO PLANT <br /> 2021 MONITORING WELL INSTALLATION PROGRAM WORK PLAN <br /> 5 <br />