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drawdown over the predicted life of mine for the south extension area will not <br />extend beyond the permit area boundary. Because drawdown will be limited to <br />areas within the permit boundary, there is no anticipated impact to adjacent <br />water users due to drawdown. <br />2) The establishment of a relatively unconfined aquifer of poor quality in the <br />backfilled pits. Spoil discharge may increase the TDS of the overburden <br />ground water system by as much as 261 % (Wolf Creek overburden) and the <br />coal ground water system by as much as 238 % (Wadge Coal). With respect to <br />both the overburden and coal seam ground water systems, elevated levels of <br />TDS and individual constituents will be localized. The impact of localized <br />water quality degradation in the coal and overburden aquifers is minimal, given <br />that the aquifers do not yield volumes sufficient for irrigation purposes, <br />baseline ground water quality in these systems is marginal to unsuitable for <br />stock watering and /or irrigation, and there are no wells completed in the <br />overburden or coal units in the mine vicinity. <br />Surface Water Effects <br />The majority of runoff from disturbed areas within the original permit area during <br />the mine life will be diverted to Sediment Ponds 005 and 006, prior to release off <br />site. Effluent from Ponds 005 and 006 flows to unnamed ephemeral gulches, and <br />ultimately Dry Creek. The majority of runoff from disturbed areas in the south <br />extension area during mine life will be diverted to Sediment Pond 016 or 017 prior <br />to discharge. Effluent from the ponds will flow into Hubberson Gulch, and <br />ultimately Dry Creek. Effects of mining on Hubberson Gulch and Dry Creek will <br />involve changes in quantity and quality, which are further described below. <br />A negligible acreage affected by the extreme eastern extension of the south area pits <br />and the neck pits between the north and south mining areas will drain to Sediment <br />Ponds 009 and 015, and eventually to Sage Creek. Measurable effects on Sage <br />Creek water quality or quantity are not projected, due to the small disturbance <br />acreage and the fact that there will be no spoil water flow to the Sage Creek <br />watershed. <br />The mining and reclamation activities will result in changes to the geomorphic <br />characteristics of ephemeral stream channels within the 005, 006, 016 and 017 <br />drainage basins. Drainage densities and channel frequencies will be reduced, and <br />channel gradients will be slightly increased in some areas; however, the operator has <br />designed and located post- mining drainage channels to minimize erosion, with riprap <br />specified where warranted. <br />During mining operations and until adequate vegetation is established, runoff and <br />erosion rates within the disturbed area will be higher than pre- mining rates. Seneca <br />Seneca II -W Findings Document 39 C -1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />