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treated and returned to the hydrologic system through periodic discharges from <br /> the waste water treatment plant. This results in negligible loss to the system. <br /> The applicant's discussion of probable hydrologic consequences identified no <br /> anticipated changes in surface water quality. All runoff from disturbed surface <br /> areas, including runoff from the refuse disposal site, drains through an approved <br /> sediment control system. All discharges are made under the conditions of the <br /> applicant's NPDES permit, and any effluent must meet the water quality <br /> standards for the receiving streams. If necessary, discharges are treated to assure <br /> compliance with water quality standards. As a result, no degradation in the <br /> quality of surface waters supplied to the alluvial valley floor is anticipated. <br /> Any groundwater supplied from strata with the potential to be affected by the <br /> proposed operations is minimal. No major aquifers have been identified in either <br /> the coal seam or the overburden. Springs in the area are associated with <br /> lenticular sands, local faulting and fracturing, and landslides. Most of the springs <br /> in or adjacent to the five year permit area are located along Sylvester Gulch. <br /> Since part of this watershed would be subject to subsidence, some of these <br /> springs could dry up. However, these springs, which supply less than 50 percent <br /> of the flow in Sylvester Gulch, are currently used as a water source for the Tony <br /> Bear Pipeline which is now owned by MCC. Loss of this water would not <br /> significantly decrease the water supply to the alluvial valley floor. <br /> No significant degradation in groundwater quality is anticipated. Following <br /> mining, new springs, fed by water supplied by the accumulation of water in the <br /> underground workings, could form. At present, the water quality of these <br /> springs under worst-case assumptions would approximate the water quality of <br /> flooded mine workings at the Oliver Mine adit where total dissolved solids <br /> concentrations range between 1050 and 1900 mg/I (see CHIS-Affects to Surface <br /> Waters section). However, flow from these springs would be such a minor <br /> contribution of the water supplied to the alluvial valley floor, no degradation of <br /> water quality in the alluvial valley floor is predicted. <br /> 3. Surface coal mining and reclamation operations are conducted to preserve, <br /> throughout the mining and reclamation process, the essential hydrologic functions <br /> of alluvial valley floors not within the affected area (Rule 4.24.2). <br /> None of the mining activities are located within the alluvial valley floor and the <br /> natural geologic and hydrologic characteristics of the valley floor would not be <br /> disturbed. In addition, mining operations are not expected to affect the quantity <br /> and quality of surface and groundwater that supply the alluvial valley floor. <br /> Minnesota Creek Drainage - Life of Mine AVF Determination: <br /> Currently, the West Elk Mine's five-year permit boundary is situated near the <br /> Minnesota Reservoir. Mining which could potentially affect the Minnesota Creek <br /> 60 <br />