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Mr.Lucas J.West <br /> November 5,2025 <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 10/30/2025 72.46 DRY N/A <br /> P7 10/30/2025 92.50 DRY N/A <br /> P8 10/30/2025 97.51 96.71 0.80 <br /> P9 10/30/2025 72.30 72 0.3 <br /> P10 10/30/2025 58.30 57.49 0.81 <br /> P11 10/30/2025 41.80 41.41 0.39 <br /> P12 10/30/2025 41.71 41.65 0.06 <br /> P13 10/30/2025 41.34 41.03 0.31 <br /> P14 10/30/2025 41.24 DRY N/A <br /> P15 10/30/2025 41.10 40.87 0.23 <br /> The leak detection system at the LTF Collection Pond was inspected October 30, 2025, and 110 gallons were evacuated <br /> from the leak detection system and pumped to the LTF. The LTF underdrain system was visually inspected October 30, <br /> 2025,and 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 October 2025,the West Pit Waste Water Treatment Plant(WWTP)was operated intermittently <br /> (3 to 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, 5,660,800 gallons (17.37 acre-feet) <br /> of treated water was discharged to the Rito Seco and 474,900 gallons (1.46 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 <br /> October. <br /> BMRI performed the monthly visual seepage expression inspections on October 30, 2025, in the historic seepage <br /> area 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 10/30/2025 24.88 <br /> BF-5R 10/30/2025 30.77 <br /> BF-6 10/30/2025 30.92 <br /> M-6 10/30/2025 DRY <br /> M-7 10/30/2025 DRY <br /> M-8 10/30/2025 DRY <br /> M-9 10/30/2025 141.21 <br /> M-10 10/30/2025 23.82 <br /> M-11R 10/30/2025 37.65 <br /> M-12 10/30/2025 174.37 <br /> M-13R 10/30/2025 125.73 <br /> M-14 10/30/2025 130.57 <br /> M-16 10/30/2025 16.96 <br /> M-17 10/30/2025 17.25 <br />