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Post mining consequences of mining will be the development of spoils aquifers in <br />the 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 <br />equilibrium is established between the backfilled pits and the surrounding aquifers, <br />a diminution of water quantity may be expected at some springs (S-1, S-5, S-23, <br />5-41) and at Temple Well No. 1. <br />Eventually, springs and seeps will emanate from the topographically lowest points <br />of 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 <br />ground water system, the largest estimated radial distance will occur in the <br />overburden aquifer, where cone-foot drawdown is predicted to occur <br />approximately 151 feet from the mined area after one year of pit inflow and <br />approximately 285 feet from the area after four years of inflow. For the Sage <br />Creek/Wolf Creek systems, the estimated drawdown in the overburden is <br />predicted to occur approximately 333 feet from the mined area after one year <br />of pit inflow and approximately 1,441 feet from the area in year 2011. No <br />pre-existing water sources with registered water rights including water wells <br />were identified in the south extension area. The maximum radius of influence <br />for one foot of drawdown over the predicted life of mine for the south <br />extension area will not extend beyond the permit area boundary. Because <br />drawdown will be limited to areas within the permit boundary, there is no <br />anticipated impact to adjacent 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 />Seneca II-W Findings Document 45 June l2, 2006 <br />Permit Renewal No. 5 <br />