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Mr.Lucas J.West <br /> August 4, 2025 <br /> Page 2 <br /> Table 2-Monthly Piezometer Elevations <br /> Monitoring Well Observation Date Piezometer Depth Depth to Water Depth of Water <br /> Identification ft ft ft <br /> P6 7/31/2025 72.46 DRY N/A <br /> P7 7/31/2025 92.50 DRY N/A <br /> P8 7/31/2025 97.51 96.70 0.81 <br /> P9 7/31/2025 72.30 71.98 0.32 <br /> P10 7/31/2025 58.30 57.49 0.81 <br /> PH 7/31/2025 41.80 41.41 0.39 <br /> P12 7/31/2025 41.71 41.65 0.06 <br /> P13 7/31/2025 41.34 41.03 0.31 <br /> P14 7/31/2025 41.24 DRY N/A <br /> P15 1 7/31/2025 1 41.10 1 40.87 0.23 <br /> The leak detection system at the LTF Collection Pond was inspected July 31,2025,and 920 gallons were evacuated from <br /> the leak detection system and pumped to the LTF. The LTF underdrain system was visually inspected July 31,2025,and <br /> the flow rate was measured to be approximately 25 gallons per minute(gpm). <br /> West Pit Waste Water Treatment Plant <br /> During the month of July 2025, the West Pit Waste Water Treatment Plant(WWTP) was operated intermittently(3 to <br /> 4 days per week) under Colorado Department of Public Health and Environment (CDPHE) CDPS Permit No. <br /> C00045675 for discharge into the Rito Seco alluvial aquifer. During the month, 7,437,800 gallons (22.83 acre-feet) <br /> of treated water was discharged to the Rito Seco and 496,100 gallons (1.52 acre-feet) of water was transferred from <br /> the West Pit to the Lined Tailing Facility(LTF). Additionally, no water was reinfiltrated into the West Pit in July. <br /> BMRI performed the monthly visual seepage expression inspections on July 31, 2025, in the historic seepage area <br /> identified in Figure 2 of the permit. No seepage expressions were observed in the historic seepage area. <br /> BMRI measured the monthly West Pit backfill, alluvial and monitoring wells as required under the QA/QC Plan. <br /> Measurements obtained for the monthly wells are shown in Table 3. <br /> Table 3-Monthly and Quarterly Groundwater Depth to Water <br /> Monitoring Well Identification Observation Date Depth to Water <br /> ft <br /> BF-4 7/31/2025 24.80 <br /> BF-511 7/31/2025 30.78 <br /> BF-6 7/31/2025 30.97 <br /> M-6 7/31/2025 DRY <br /> M-7 7/31/2025 DRY <br /> M-8 7/31/2025 DRY <br /> M-9 7/31/2025 141.16 <br /> M-10 7/31/2025 24.22 <br /> M-11R 7/31/2025 37.75 <br /> M-12 7/31/2025 174.24 <br /> M-13R 7/31/2025 125.69 <br /> M-14 7/31/2025 130.52 <br /> M-16 7/31/2025 22.19 <br /> M-17 7/31/2025 30.12 <br />