2006-08-28_REVISION - M1977424 - Laserfiche WebLink

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Permit M77-424 Amendment 1 Exhibit G Page 2 of 13 4) Projected Amounts of Water to Supply the Project Water Requirements This information is presented in the original mine permit as required by rules and regulations existing at the time of submittal. This information is not relevant to this amendment as no water requirements exist for the project. Please refer to Exhibit G of the original permit for more detailed information. 5) National Pollutant Discharge Elimination System Permit A permit from the National Pollutant Discharge Elimination system was obtained prior to initial water discharges at the mine as required by rules and regulations existing at the time of submittal. The NPDES discharge permit number is COG- 600452. Please refer to Exhibit G of the original permit for more detailed information. Additional Information The following additional information i$ presented to facilitate a better understanding of water conditions at the Logan Wash Mine. Retort Water Discharge Water discharge into the evaporation pond through the water transmission pipeline has been measured from one or both of two manholes at the uppermost and lowermost manhole stations along the pipeline from January of 1992 through the present. Water flowing into the pond originates as precipitation and snowmelt that percolates through the strata above the Logan Wash Mine and into the retorts. Some lateral groundwater discharge from local aquifers may also contribute to retort water flows. Flows measured at the Upper and Lower manholes on the pipeline show an average flow rate of 7,062.67 gallons per day (4.81 gallons per minute). Note that this average includes a period when non-retort mine water was combined with retort water and conveyed to the evaporation pond. Retort Water Quality Chemical analysis of the retort water has been conducted sporadically in the past. The analytical data indicate that the retort water is typically high in total dissolved solids. Organic solute detection has vazied from minor concentrations to no detections. At the pond, the light hydrocazbons of benzene, toluene, ethylbenzene, and xylene (BTEX) have not been detected. Historical water quality data aze presented in Table 2.