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Aquifer tests were performed at two wells. One well failed during the test. The <br />transmissivity calculated at the other well was 0.03 ft' per day, while storativity has <br />been estimated to be on the order of 1 x 10-4. <br />Six wells have been sampled for water quality characteristics, five within or adjacent <br />to the original permit area and one within the south extension area (4W). 4W has <br />been dry since 2002. Due to safety concerns because of proximity to the highwall, <br />it was abandoned in August 2003 and was replaced in 2004, by WW25. Typically, <br />the quality of Wadge seam water varies from place to place. Generally, sulfate, <br />manganese and total dissolved solids exceed both U.S. EPA and National Academy <br />of Sciences recommended drinking water criteria. These criteria may be found in <br />Volume 3, Tab 7, Tables 7-20 and 7-43 of the permit application. These waters are <br />unsuitable for use as a drinking supply, but may be used for livestock watering. <br />These waters also pose a high salinity hazard to intolerant plants, and therefore may <br />be unsuitable for use as irrigation water. <br />Wadge Coal Overburden <br />Six wells are used to monitor water quality and/or depth to water in the <br />Williams Fork Formation overburden above the Wadge coal seam. Two of the wells, <br />40V 1 and 4OV2, were down -gradient wells in the south extension area. Both of <br />these wells have been abandoned. A replacement Wadge overburden well, WOV25, <br />was drilled in 2004. <br />The Williams Fork is a 50- to 500 -feet thick sequence of sandstone, siltstone, shale, <br />and thin coal, including the Lennox Coal Seam. Ground water in the Williams Fork <br />tends to flow downdip. The movement of water and the horizontal extent of the <br />formation are limited by outcrops in the eastern and central parts of the permit area. <br />Generally, the Williams Fork is found to be in an unconfined state; however, locally <br />or seasonally, the formation may exhibit semi -confined conditions. Seasonal <br />fluctuations are probably the result of recharging and dewatering a perched aquifer <br />within the formation. <br />Although aquifer tests were not performed on the overburden at the site. Aquifer <br />characteristics have been extrapolated from the former Colorado Yampa Coal <br />located about 15 miles southeast. Data obtained from these tests indicate that <br />transmissivity values for the overburden could range from 3 to 20 gallons per day <br />per foot (0.4 to 2.7 ft2 per day), while storativity may vary from 1 x 10-2 to 1 x 10-5 <br />as local conditions change. <br />Water quality analyses generally indicate that this is a magnesium -calcium <br />bicarbonate water with elevated levels of iron, manganese, and TDS. The high iron, <br />TDS and manganese values preclude use of this water as a drinking supply. Williams <br />Fork water is suitable for stock watering and irrigation of salt tolerant plants. <br />15 <br />