GENERAL55781 - Laserfiche WebLink

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-zo- The applicant's discussion of probable hydrologic consequences has identified no anticipated changes in surface water quality. All runoff from disturbed surface areas will drain through an approved sediment control system. No material damage to the quality of surface waters supplied to the alluvial valley floor is anticipated, due to the sediment control at the mine site and the fact that surface disturbances are two miles upstream from the AVF. The potential for any impact of the operation on ground water in bedrock aquifers is minimal. To date, the small amount of water which has seeped into the mine from the roof, floor, and the "E" coal seam has been augmented by water pumped from the surface and used in the mining operation. The coal seams of the Mesaverde Formation are not aquifers. The strata immediately above and below the coal seams contain only localized perched aquifers with low transmissivities, and are therefore insiynificant. Therefore, the potential for material damage to the quantity of water supplied to the alluvial valley floor is minimal. There is a potential for a slight increase in total dissolved solids (TDS) concentrations in the North Fork alluvial ground water as a result of percolation through the coal stockpiles, the refuse material in the East mine bench and the sediment ponds. The percolation could occur during snowmelt and rainfall. The potential for this water quality deyradation is considered insignificant for the following reasons. First, the small amount of leachate that would be produced would probably oe diluted rapidly by the existing water in the alluvial ground water system. Second, the irrigated croplands are over 2 miles from the disturbed areas at the Hawk's Next Mine. This should be a sufficient distance for any deyraoed water to reach acceptable levels. Third, the potential impact will be short-term. Once mining operations are completed, the disturbed areas and sediment ponds will be reclaimed and the potential for water quality degradation will cease. For a discussion of the cumulative impacts of mining operatons on the water quality of the North Fork, the reader is referred to Section IX: Cumulative Hydrologic Impact Study, of this document. 3. Pursuant to RuleL.06.8(5)(a)(iii), the Division finds that surface coal mining and reclamation operations would be conducted to preserve, throughout the mining and reclamation process, the essential hydrologic functions of alluvial valley floors not within the affected area. None of the mining activities are located within the alluvial valley floor and the natural geologic and hydrologic characteristics of the alluvial valley floor will not be disturbed. Mining operations are not expected to materially damage the quantity and quality of surface and ground water that supply the alluvial valley floor. The proposed operation is in compliance with the requirements of this section.