2006-08-28_REVISION - M1977424 - Laserfiche WebLink

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Permit M77-424 Amendment 1 EXHIBIT G WATER INFORMATION 1) Statement of Effect on Surface or Groundwater Systems Exhibit G Page 1 of 13 The construction of the water transmission pipeline and evaporation pond was not expected to directly affect surface or groundwater systems, and have not affected any surface or groundwater systems since construction in 1984. The water transmission pipeline crosses Logan Wash in one location and was buried at a depth of at least 6-feet so as not to interfere with flows that may occur within Logan Wash. Logan Wash is an ephemeral drainage and surface flows have only been observed after intense local thunderstorms (flows have not been observed during spring snowmelt periods). Several springs are present in the area and are depicted in Exhibit C, Sheet 4. The discharge from these springs vary in magnitude and frequency. Flows have been estimated to range from less than 1 gallon per minute (gpm) to several gpm depending on location, time of year, and antecedent precipitation. Springs have been observed at the very upper elevations of Logan Wash at the heads of major tributary drainages above the Mahogany Ledge. Water from these springs quickly infiltrates into the colluvium and scree that make up slopes and valley fill. None of the identified springs are adversely impacted by the pipeline or pond. In addition, the pipeline was also installed at a depth that does not encounter any shallow aquifers along its length. Several test boreholes drilled along the pipeline did encounter wet soil, but the pipeline has not interfered with the groundwater flows in those areas. The evaporation pond was also constructed at a depth that does not interfere with any shallow aquifers that may exist in the area. For more information concerning the test boreholes completed in the area please refer to the Geotechnical Stability Exhibit. In addition, drawings and specifications for the pipeline and pond can be found in the sheets contained in Exhibit D. 2} Effect on Surface or Groundwater Systems The construction of the water transmission pipeline and the evaporation pond does not directly affect surface or groundwater systems. 3) 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.