2012-01-05_REVISION - C1980005 (8)

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use. Well yields for the Wadge Coal and overburden have been reported at between 2 and 5 gpm. In the vicinity of the Seneca II Mine site, both units have been used for domestic and livestock purposes. The Wadge Coal has been mined in the northern portion of the permit area (Sand Wash Ground Water Basin) in the past. During previous permit terms, the Wadge Coal was extracted from the southeastern portion of the permit area within the Twentymile Park Basin. The portion of Twentymile Park in which the Seneca II Mine is located has been identified as a recharge area. As such, the potential impacts of mining were previously identified as: (1) Interruption of the aquifer by the physical removal of the coal and its overburden. Mining of the coal was predicted to interrupt the aquifer function upgradient of Twentymile Park. This interruption was further predicted to reduce the recharge potential to the down - gradient aquifer for a short period of time. (2) Resaturation of spoils following backfilling of discrete mining areas. A portion of the spoil water was predicted to recharge the undisturbed Wadge Coal and overburden immediately down - gradient. This recharge water was predicted to be high in TDS and other constituents. The concentrations of these constituents are expected to be greater than that which existed in the Wadge Coal and overburden aquifer prior to mining. (3) Recharge of creeks within the Twentymile Basin through Wadge overburden sub -crops and outcrops was predicted. This recharge may be directly affected by the addition of the poor quality spoil discharge water during base flow conditions, or indirectly by the addition of this water to associated alluvial bodies. Recharge to the surface system could potentially be affected by the interruption of the aquifer due to removal by mining. Furthermore, upon indirect recharge by the spoil aquifer, a plume of poor quality water could diminish the water quality of the surface water system within Twentymile Park. The alluvial aquifer system in the Fish Creek Drainage (including Bond and Cow Camp Creeks) was predicted to be affected by mining activities. During past mining, surface runoff from the disturbed areas was contained in sediment ponds prior to discharging from the site. Pond 008 at the Seneca II Mine has historically discharged regularly throughout the year to Bond Creek. This drainage, at various times of the year, recharges the associated alluvial /colluvial aquifers with the sediment pond discharge. This sediment pond discharge is typically higher in dissolved constituents than the naturally occurring runoff from 19