2025-06-23_REVISION - M1980244 (94)

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Newrnont.. CRIPPLE CREEK & VICTOR PO Box191 100 N.CRIPPLE CREEK&VICTOR Victor 8086Street Victor CO 80860 and the stabilized water level. Add the volume of the water which occupies the pump's tubing to this calculation. This combined volume of water needs to be purged from the well after the water level has stabilized before samples are collected. During purging monitor field parameters (pH, temperature, & conductivity). Purging is considered complete and sampling may begin when all the indicator field parameters (below) have stabilized. Achievement of turbidity levels of less than 5 NTU, and stable drawdowns of less than 0.3 feet, while desirable, are not mandatory. However, some wells yield such low volumes of water that this protocol cannot be followed. When sampling a low yield well evacuate the well to dryness once.Within 24 hours of this purge, collect, preserve, and handle the sample(s) according to normal procedures. Standard/Well-Volume Method may also be utilized for sampling monitoring wells, for this method three casing volumes will be evacuated prior to sampling. Measure • the stabilization criteria outlined below after each well volume is evacuated (i.e., if the well volume is 5 gallons, take measurements after evacuation of 5, 10, and 15 gallons). On the field form, record the volume of water evacuated, all stabilization parameters, and time that the measurements were made. After three well volumes have been purged (appendix E, well evacuation calculation) check the last two sets of measurements to determine if the field parameters have stabilized. If the field readings have not stabilized purge another well volume and take field measurements. Repeat until stabilized. Stabilization criteria are achieved when the following parameters are met over three consecutive readings. • Temperature - ±3%, • Specific Conductivity - ±3% • pH - ± 0.1 • Dissolved Oxygen - (10% for values greater than 0.5 mg/L, if three Dissolved Oxygen values are less than 0.5 mg/L, consider the values as stabilized) • Turbidity - (10% for values greater than 5 NTU; if three Turbidity values are • less than 5 NTU, consider the values as stabilized) • Oxidation/Reduction Potential - ±10 millivolts Department THIS DOCUMENT IS UNCONTROLLED IN HARD COPY FORMAT Doc Id: SLIt Date of This Issue--/--/-- Date of Next Review:--/--/-- Page 24 of 73