2011-01-13_PERMIT FILE - C1980006 (2)

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Section 780.21 (b) Continued. n L~ Ground Water Quantity Protection Potential Impacts on Ground Water Quantity. Mining activites have the potential of creating changes in the quantity of ground water in terms of depths of piezometric water levels, recharge capacity, specific yield, storage capaclty and geographical location. The potential mechanisms of impact are: 1) moving and replacing overburden so as to cause physical modifica- tion and relocation of recharge areas; and 2) dewatering caused by pumping ground water from pits or from supply wells for operational requirements. A detailed discussion of potential impacts is pre- sented under Section 780.21 (c). The only saturated stratum to be affected by mining will be the Sudduth coal seam. The overburden is not saturated, and the overlying and underlying strata are occluded from the coal aquifer by confining layers. A more de- tailed discussion of the ground water hydrology in the mine plan • area is presented under Section 779.15. Protection and Mitigation. Changes in ground water quantity will occur as a result of mining with respect to recharge capability, specific yield and storage capacity. These changes result from the fact that broken over- burden increases all of the above factors as discussed in detail under paragraph (c) of this Section. Because mining will remove the shale above the coal aquifer, the horizontal extent of the recharge area will increase significantly. Thus, mining operations will not only restore, but will actually increase premining re- charge capacity, specific yield and storage capacity within the mine plan area. Dewatering of the pits will cause temporary drawdown of the adja- cent undisturbed portion of the coal aquifer, as discussed in Section 780.21 (c). This water will be pumped into adjacent sedi- mentation ponds. No meaeureable drawdowns are expected outside the adjacent area. Because any drawdown will be temporary and because 780-106