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• The "E" and "F" coal seams have low sulfur content. Organic sulfur <br />predominates, ranging between 0,32% and 0.61% with a mean of 0.45% in the "F-' <br />seam and between 0.39% and 0.53%, with a mean of 0.46% in the "E" seam. <br />Pyritic sulfur is low, ranging from none to 0.12% for the "F" seam samples <br />with a mean value of 0.05%. Content of pyritic sulfur ranges from 0.01% to <br />0.12% in the "E" seam with a mean value 0.04%. None of the analyses reported <br />for "E" and "F" coal samples contained sulfate sulfur. These analyses <br />indicate low acid-forming potential on the part of the coals. The exposed <br />coal within the mine workings should not form acid mine water. Analyses of <br />roof and floor materials from the "E" ad "F" coal seams have even lower total <br />sulfur values, averaging 0.26% for the roof and floor materials of the "F" <br />seam and O.i4% for the materials associated with the "E" seam. It is also <br />believed that these materials lack the potential to form acid mine waters, <br />During mining, the residence time of inflow waters will be short, since <br />regular discharge of the water will be needed to maintain the operation of the <br />mine, The inflow water will have relatively little time to chemically react <br />with the mine materials, This will result in only slight increase in <br />dissolved solids in the water discharged to the surface during operations, <br />The water discharged from the No. 5 Mine is a sodium bicarbonate type with a <br />mean total dissolved solids value of 831 mg/1. The mean value for dissolved <br />sodium is 312 mg/1. Since the mine water is discharged under NPDES permit <br />directly into the Williams Fork River, its maximum potential impact will be on <br />the quality of the Williams Fork River and alluvial water. <br />• Water in the Williams Fork alluvium is also a sodium bicarbonate type. While <br />this water averages higher salinity than the mine discharge water, the sodium <br />content is lower. Other dissolved constituents of the the alluvial water, <br />however, characteristically exceed those of the water discharged from the <br />mine, There has been some increase over time in the salinity of the water in <br />the Williams Fork alluvium in the permit area, but there is no evidence that <br />this change is attributable to the discharge of water from the mine. In fact, <br />all wells which are monitored for water levels and water quality in the <br />Williams Fork alluvium are located upstream from the point of mine water <br />discharge, <br />Within the permit area, the mine water is not the only ground water discharged <br />into Williams Fork River that might have an impact on its quality or that of <br />associated alluvial water. Water seeping from the old Williams Fork Strip Pit <br />No. 1 also enters the Williams Fork River downstream of the alluvial <br />monitoring sites. This water is slightly lower in total dissolved solids but <br />higher in sodium than the W111tams Fork alluvial water. The flow from this <br />source, however, averaged only 23 gpm during 1985, Discharge from the mine <br />during 1985 averaged in excess of 600 gpm. The potential quailxy impact of <br />this seep is, therefore, neglible. <br />The mine water itself will undergo some changes both in quality and quantity <br />in the future as inflow into the No. 6 Mine is added to the discharge into the <br />Williams Fork River, Water from the No. 6 Mine is forecast to be generally <br />similar to that presently discharged. It is, therefore, the impact of the <br />additional volume of mine water that is the greater concern. <br /> <br />-34- <br />