Laserfiche WebLink
locations are shown on Exhibits 7-1 (for the original permit area) and 7-1 A (for the <br />South Extension Area). <br />Ground water studies in conjunction with the Seneca II -W Mine site have been <br />concentrated in the Upper Mesaverde Group and alluvial aquifers. Specifically, <br />aquifer characteristics and/or water quality analyses have been performed in the <br />Wolf Creek underburden, Wolf Creek coal, Wolf Creek overburden, Sage Creek <br />coal, Sage Creek overburden, Wolf Creek/Wadge interburden, Wadge coal, Wadge <br />coal overburden, and the Hubberson Gulch alluvium. Quantity and quality data have <br />also been collected from ten springs and seeps in and adjacent to the permit area, and <br />from three spoil springs that have developed on reclaimed areas. The current <br />monitoring plan requires monitoring of water quality and/or water levels at specified <br />intervals at thirteen bedrock wells, two alluvial wells, four natural springs and seeps <br />and five spoil springs. Each year following snowmelt, any additional spoil springs <br />with discharge of at least 5 gpm are documented, monitored in spring and fall, and <br />reported in the Annual Hydrologic Report for the year. <br />Each of the identified aquifer zones is hydraulically discontinuous with the units <br />above and below. Therefore, each aquifer will be discussed as a separate entity. <br />Wolf Creek Seam <br />The lowest coal in the Williams Fork Formation of the Mesaverde Group is the Wolf <br />Creek seam. <br />Depth to water and water quality measurements have been made at three sites in and <br />adjacent to the original permit area. Water levels in the Wolf Creek at all three sites <br />exhibit confined conditions. Dependent upon proximity to the outcrop recharge area <br />(paralleling the Sage Creek anticlinal axis) and local structure, each well has varying <br />amounts of head. Ground water flows from the recharge area to the center of the <br />basin. Therefore, the major component of flow appears to be toward the west. <br />Aquifer tests were performed on the two updip wells during the summer of 1980. <br />These tests indicate that the Wolf Creek is a fairly well confined aquifer which <br />transmits limited amounts of water. One well was pumped at an average of 1.2 <br />gallons per minute for about 3 1/2 hours, and produced no observable drawdown at <br />an observation well 20 feet away. Transmissivity values calculated for the Wolf <br />Creek range from 0.02 ft2 per day (0.149 gallons per day per foot) for well 3WC, to <br />0.001 ft2 per day (0.007 gallons per day per foot) in the two wells tested. Due to the <br />low water yield and transmissivity values, the storativity value of the Wolf Creek <br />seam is estimated to be about 1 X 10-5. These values, both transmissivity and <br />storativity, would appear to be quite low. Aquifer test data, however, substantiate <br />these values. Due to the highly lenticular and discontinuous nature of the Mesaverde <br />Group, it is thought that transmissivity and storativity will be areally variable. <br />The quality of Wolf Creek coal water is slightly acidic, very hard and saline. Based <br />on data presented, the water type changes from calcium/sulfate to <br />12 <br />