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precipitation, overland flow, and discharge from the Williams Fork formation <br />overburden and the coal seams being mined. <br />The backfilled pits in and of themselves will display unconfined conditions; <br />however, the pits will be surrounded on the sides and be underlain by relatively <br />confining units. The underlying material will be even more confining than the sides. <br />As water enters the reclaimed areas, it will tend to migrate through the spoils toward <br />the lowest point in the pit. While some of this water may be lost to the walls, the <br />major portion of it will stay in the pit, as the permeability of this material is greater <br />than that of either the walls or the floor. It is projected that the water quality of spoil <br />aquifers at the Seneca II -W Mine site will approximate that at the nearby Seneca II <br />Mine. The Seneca II Mine spoil aquifers exhibit elevated levels of total dissolved <br />solids, magnesium, manganese, molybdenum, and sulfate. Complete water quality <br />analyses of two spoils aquifer wells are published in the Seneca II Mine 1984 Annual <br />Hydrology Report, Appendix B. <br />As the aquifer is developing, the water will be of slightly poorer quality than the <br />above assumptions, but as the more easily leached constituents are lost, the quality <br />should approximate that at the former Seneca II Mine. Analysis of spoils water from <br />the former Seneca II Mine indicates that this magnesium -calcium sulfate water has <br />elevated levels of sulfate and magnesium. TDS values vary between 2,200 and 4,000 <br />mg/l. <br />Eventually, water at Seneca II -W Mine will begin to discharge to the surface as the <br />water elevation exceeds the ground level or when sufficient head is developed. <br />The primary impact of Seneca II -W mining operations (including south extension <br />operations) on surface water quality will be an increase in total dissolved solids <br />(TDS) concentration resulting from the occurrence of spoil springs after backfilled <br />spoil in the mine pits has become saturated. The projected impacts on each of the <br />affected drainages near the permit area are summarized below. <br />Hubberson Gulch <br />SP predicts spoil springs in the Seneca II -W South Area will increase TDS in <br />Hubberson Gulch upstream from the Pond 006 drainage from 676 mg/l to 1,787 <br />mg/1. This prediction was calculated from mean discharges and mean TDS <br />concentrations for June - September data for the entire period of record. This <br />projection exceeds the Division's suspect level for material damage for water used <br />to irrigate hay crops. SP estimated production losses resulting from the increase in <br />salinity. Based on the information provided by SP, the Division finds that no <br />material damage will occur. See Section B.XII of this document for additional <br />details. <br />25 <br />