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in Hubberson Gulch exhibit TSS levels from 5 mg/l to 606 mg/1 with an average of 100 mg/1. The total suspended solids increase to Hubberson Gulch that can be attributed to mining is expected to be minimal. Once vegetation is successfully reestablished, the erosion rates are expected to return to the pre-mining level of approximately 140 tons/miZ/yr. Sediment ponds will act to control flood flows from the disturbed area. The ponds will regulate flood discharges, minimizing the impact of the floods. The ponds are not expected to significantly reduce the quantity of runoff water available in Dry Creek. The mine area makes up only a small portion of the Dry Creek watershed (0.9%). The major impact of mining will be the development and subsequent discharge to the surface system of spoils aquifer waters. As each successive pit is reclaimed in the Wadge and Wolf Creek/Sage Creek mining areas, a spoils aquifer will begin to develop. The water necessary to recharge these aquifers will be derived from precipitation, overland flow, and discharge from the Williams Fork formation overburden and the coal seams being mined. The backfilled pits in and of themselves will display unco~ned conditions, however the pits will be surrounded on the sides and be underlain by relatively confining units. The underlying material will be even more confining than the sides. As water enters the reclaimed areas it will tend to migrate through the spoils toward the lowest point in the pit. While some of this water may be lost to the walls, the major portion of it will stay in the pit, as the permeability of this material is greater than that of either the walls or the floor. It is projected that the water quality of spoil aquifers at the Seneca II-W Mine site will approximate that at the nearby Seneca II Mine. The Seneca II Mine spoil aquifers exhibit elevated levels of, total dissolved solids, magnesium, manganese, molybdenum, and sulfate. Complete water quality analyses of two spoils aquifer wells are published in the Seneca II Mine 1984 Annual Hydrology Report, Appendix B. As the aquifer is developing, the water will be of slightly poorer quality than the above assumptions, but as the more easily leached constituents are lost, the quality should approximate that at Seneca II Mine. Analysis of spoils water from the Seneca II Mine indicates that this magnesium-calcium sulfate water has elevated levels of sulfate and magnesium. TDS values vary between 2,200 and 4,000 mg/I. Eventually, water at Seneca II-W Mine will begin to discharge to the surface as the water elevation exceeds the ground level or when sufficient head is developed. Seneca II-W Findings Document 47 June 12, 2006 Permi[ Renewal No. 5