2012-10-01_REVISION - M1977310 (10)

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JD -6 Mine Environmental Protection Plan 49 one - hundredth of a foot from the top of the well- casing using an electrical water level sounder, before purging and sampling the well. The water level sounder will be cleaned regularly with an environmental grade detergent (Alquinox or Liquinox) before use. All parts of the sounder that will contact groundwater will be rinsed with distilled water before placement in the well. Groundwater purging and sampling will be performed according to standard environmental protocols. For conventional purging, a minimum of three well volumes will be purged before collecting the sample. The pH, specific conductance, and temperature of discharged water will be monitored during purging and recorded on the field sampling record. Well purging will be sufficient when at least 3 volumes have been purged, the water is clear without visible turbidity, and successive measurements for field parameters vary by less than 10 percent. (The list of field parameters is provided in Section 10.1.5.) For very low volume wells, the wells may be pumped or bailed dry and allowed to recover overnight before collecting the sample. In this case, purging of a minimum of three well volumes would not be required. Dedicated sampling pumps and low flow (micro - purge) sampling methods may also be used to collect groundwater samples. Only certified clean bottles obtained from the analytical laboratory will be used for samples. Samples for dissolved constituents will be field filtered (0.45 µm) and preserved immediately or will be unfiltered /unpreserved in the field and sent to the laboratory for filtration. If a sample for dissolved constituents is not filtered in the field, an acid preservative shall not be added in the field. All sample containers will be clearly labeled with the well identification, date and time of sample collection, parameters to be analyzed, filtered or unfiltered, preservatives, and the samplers' initials. Samples will be kept cool from the time of collection to receipt by the analytical laboratory. Chain of custody forms and custody seals provided by the laboratory will be used for all samples shipped to the laboratory. Samples will be stored on ice for shipment to the laboratory via express carrier. 10.1.5 Groundwater Analytical Suite Groundwater will be monitored for field parameters and samples will be sent the laboratory for analysis of laboratory parameters. Parameters to be measured in the field and recorded on the field sampling record will include water level, temperature, pH, electrical conductivity, and dissolved oxygen (Table 26). Laboratory parameters for groundwater samples include 37 analytes listed in Table 27. The analytical suite for the project has been developed based on Colorado agricultural groundwater standards, and EPA drinking water standards. The analytical suite will be reviewed annually, and may be modified to add or exclude constituents, as necessary to meet the goals of the monitoring program. Table 26. Field Parameters for Groundwater Monitoring Parameter Precision/Units Water Level 0.01 ft Temperature 0.1 °C pH 0.01 s.u. Electrical Conductivity 1 µmhos /cm Dissolved Oxygen 0.01 mg /L, 1% ORP 1 mV 4148A.120927 Whetstone Associates