2010-12-09_GENERAL DOCUMENTS - C1982057

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Wolf Creek Seam The lowest coal in the Williams Fork Formation of the Mesaverde Group is the Wolf Creek seam. Depth to water and water quality measurements have been made at three sites in and adjacent to the original permit area. Water levels in the Wolf Creek at all three sites exhibit confined conditions. Dependent upon proximity to the outcrop recharge area (paralleling the Sage Creek anticlinal axis), and local structure, each well has varying amounts of head. Ground water flows from the recharge area to the center of the basin. Therefore, the major component of flow appears to be toward the west. Aquifer tests were performed on the two updip wells during the summer of 1980. These tests indicate that the Wolf Creek is a fairly well confined aquifer which transmits limited amounts of water. One well was pumped at an average of 1.2 gallons per minute for about 3 1/2 hours, and produced no observable drawdown at an observation well 20 feet away. Transmissivity values calculated for the Wolf Creek range from 0.02 ft2 per day (0.149 gallons per day per foot) for well 3WC, to 0.001 ft2 per day (0.007 gallons per day per foot) in the two wells tested. Due to the low water yield and transmissivity values, the storativity value of the Wolf Creek seam is estimated to be about 1 X 10-5. These values, both transmissivity and storativity, would appear to be quite low. Aquifer test data, however, does substantiate these values. Due to the highly lenticular and discontinuous nature of the Mesaverde Group, it is thought that transmissivity and storativity will be aerially variable. The quality of Wolf Creek coal water is slightly acidic, very hard and saline. Based on data presented, the water type changes from calcium/sulfate to sodium/bicarbonate down gradient. Well 3WC displayed the only case of elevated iron levels within the Wolf Creek coal. Well 2WC located down gradient has the lowest levels of TDS and sulfate, indicating that the sulfate is being precipitated from the water as it moves down gradient. Two wells were established to monitor water levels and quality in the seam within the south extension area, down-gradient of mining areas (4WC and WWC24). Water levels at 4WC are generally over a hundred feet deeper than the adjacent Wadge Coal Well 4W, indicating no hydraulic communication between the two units. 4WC was sampled 1983 to 1985 to establish baseline conditions, and sampling was resumed in 1997 for monitoring purposes. The well displays a MgCa-HC03SO4 type water with average TDS value of 812 mg/1. Due to safety concerns because of proximity to the highwall, the well was abandoned in 2003. Well WWC24 was drilled in August 2001 but was damaged by landslide in the spring of 2003, and subsequently abandoned. A replacement well (WWC25) was drilled in the summer of 2004. WWC24 was a flowing well. Initial samples displayed a Na-HC03 type water with TDS values of 640 and 820 mg/l. Seneca Il-W Findings Document 29 C1982057 Permit Renewal No. 5 December 9, 2010