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Spring S -23 may be impacted by mining. S -23 feeds Temple Pond No. 1, which is <br />also registered and is upgradient of mining activities. <br />It will probably be a number of years after mining comes closest to these springs <br />that the effects in quantity and /or quality are observed. Again, this is due to the low <br />transmissivity and storativity values associated with the local strata. Most of these <br />springs are used for stock watering. Mining should not prohibit this use, because <br />TDS levels will not surpass EPA limitations for stock watering purposes. Post <br />mining consequences of mining will be the development of spoils aquifers in the <br />backfilled pits. The reclaimed pits will have the highest permeability /porosity <br />values of any local aquifers. The backfilled pits will induce recharge from <br />precipitation and surface runoff, from up gradient in the Williams Fork formation, <br />and from downgradient in the Williams Fork and Wadge coal. Until an equilibrium <br />is established between the backfilled pits and the surrounding aquifers, a diminution <br />of water quantity may be expected at some springs (S -1, S -5, S -23, S -41) and at <br />Temple Well No. 1. <br />Eventually, springs and seeps will emanate from the topographically lowest points of <br />the reclaimed pits. These waters will be characterized by high levels of iron, <br />manganese, total dissolved solids, and possibly boron. Unless this water is <br />intercepted by holding ponds, it will add flow to the unnamed drainage directly <br />below the mining area and eventually to Hubberson Gulch and Dry Creek. This <br />flow may be expressed as surface flow, or as an increased (elevated) water table, <br />dependent upon local conditions. It is projected that the concentrations of these <br />parameters will decrease with time as the readily dissolvable elements are leached <br />until an equilibrium level is reached. Further discussion of this is found under the <br />Surface Water Effects of the Probable Hydrologic Consequences section. <br />Ground Water Effects (South Extension Area Addendum) <br />Probable hydrologic consequences to the ground water regime as a result of mining <br />the Wadge, Sage Creek and Wolf Creek coal seams within the south extension area <br />have been assessed. Localized effects to the hydrologic system will include: <br />1) The drawdown of ground water, due to pit dewatering. For the Wadge ground <br />water system, the largest estimated radial distance will occur in the overburden <br />aquifer, where a one -foot drawdown is predicted to occur approximately 151 <br />feet from the mined area after one year of pit inflow and approximately 285 <br />feet from the area after four years of inflow. For the Sage Creek/Wolf Creek <br />systems, the estimated drawdown in the overburden is predicted to occur <br />approximately 333 feet from the mined area after one year of pit inflow and <br />approximately 1,441 feet from the area in year 2011. No pre- existing water <br />sources with registered water rights including water wells were identified in the <br />south extension area. The maximum radius of influence for one foot of <br />Seneca II -W Findings Document 38 C- 1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />