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~J -44- ~~ u Gnu ~° The Trapper Mine may affect ground water quality through the discharge of spoil waters to the first White sandstone. The first White sandstone is exposed only in the upper portion of the Trapper Mine's highwall. Given the low permeability of this unit, the quality and quantity impacts to the first White sandstone will be confined to the areas adjacent to the underground workings of the Eagle No. 9 Mine, the recharge areas excavated by the Trapper Mine, and the post-mining highwall surface area exposed in the Trapper Mine. Spoil waters would enter this aquifer only through the exposed highwall at the Trapper Mine and only after spoil water levels have reached the exposed highwall section. This impact is expected to be minor. The impacts to the first White sandstone by the Eagle No. 9 Mine are not known. Lenticular and interbedded sandstone and coal aquifers of the Upper Williams Fork Formation may be impacted by the Eagle No. 5 and No. 9 Mines and Trapper Mine. Both the quality and quantity of ground water in these localized aquifers may be impacted. These aquifers are not put to beneficial use, but they may support springs and seeps that have only minor discharge rates. Therefore, the cumulative impacts will be minimal. The Empire Energy and Trapper Mines may impact the quantity of ground water in the Big Bottom alluvium. Both mines may deplete the quantity of water in the alluvium of Big Bottom by reducing discharge of rock aquifers to thfs alluvium. The Trapper Mine will deplete recharge waters of aquifers tributary to the Big Bottom alluvium. The Empire Energy Eagle No. 9 Mine may divert alluvial waters into underground mine workings through affected strata of the Upper Williams Fork Formation. Analyses conducted by Empire Energy Corporation on the impacts of mining in the Eagle No. 9 Mine predict no significant depletions of ground water in the Big Bottom alluvium. The combined impacts of the Eagle No. 9 and Trapper Mines may be significant. The Trapper and Eagle Mines may impact the quality of ground water in the Big Bottom alluvium. The Trapper Mine may impact the quality of water in the Big Bottom alluvium through the discharge of spoils waters. This spoils water discharge will be minor and use of alluvial ground water may not significantly be damaged. The Eagle No. 9 Mine may impact the ground water quality of the Big Bottom alluvium following mining. This mine may discharge mine waters through interconnecting faults, fractures, and affected strata. The greater subcrop area of the affected aquifers over the Eagle No. 9 Mine, and the potential for greater frequency of fracturing over mine workings may result in a more significant impact to the Big Bottom alluvial ground water quality from the Eagle No. 9 Mine than the Trapper Mine. Cumulative Surface Water Impacts The projected surface water effects (7able I) for the Sugarloaf, Foidel Creek, and Empire Energy Mines were added to the projected hydrologic effects from the Kaman Tempo study. For the Foidel Creek Mine, the worst-case mine water discharge was expected to be 1.95 cfs and have a maximum total dissolved solids concentration of 800 mg/l. The long-term effect is to discharge 0.14 cfs of affected ground water (3,200 mg/1) to the Fish Creek drainage.