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3.0 HYDROLOGY AND MINE DEVELOPMENT <br />This monitoring period from October 1, 2002 to September 30, 2003 has provided the hydrologic <br />information necessary to assess the adequacy of monitoring program, the adequacy of the <br />mitigative measures designed to protect the hydrology, and identify and quantify impacts that <br />may have occurred during this period. <br />3.1 Mining Related Hydrologic Impacts <br />The only impacts identified to date include: <br />• Withdrawal of water for the mine from the lagoon adjacent to the White River thus slightly <br />reducing the flow in the White River. BME has legal right to this water. <br />• Discharge of storm water from pond DP-1 into Scullion Gulch, a White River tributary. <br />Discharges contained lower TSS than typical receiving stream flows during storm events. <br />• Decline in piezometric level in wells in close proximity to mine workings. Holes that were <br />mined through typically turned dry. <br />• Subsidence in Red Wash resulting in ponding of surface water. The ponds quickly fill with <br />clay and silt with Red Wash maintaining its original channel. <br />• Subsidence in Scullion Gulch with no surface hydrologic consequences observed to date. <br />Not enough precipitation has occurred to truly test the system. Runoff was rarely observed <br />in the impacted sections of Scullion Gulch prior to mining. <br />3.2 Comparison of Projected Impacts with Observed Impacts <br />The comparisons of the projected impacts (probable hydrologic consequences) with the <br />observed impacts are discussed in the following. <br />The water withdrawal rate from the lagoon at the White River this reporting year was estimated <br />at 144,986,946 gallons or 445 acre-feet. This compares with an expected withdrawal rate of <br />552 acre-feet per year at full production. <br />The decline in piezometric levels in bedrock zones "upper sandstone facies", "siltstone/coal <br />facies", and "lower sandstone facies" was anticipated as probable impacts as the result of <br />13 <br />