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<br />Wolf Creek Seam <br />The lowest coal in the Williams Fork Formation of the Mesaverde Group is the <br />Wolf Creek seam. The Wolf Creek seam is the first aquifer encountered below <br />the bottom of the mine pit. <br />Depth to water and water quality measurements have been made at three sites in <br />and adjacent to the permit area. Water levels in the Wolf Creek at all three <br />sites exhibit confined conditions. Dependent upon proximity to the outcrop <br />recharge area (paralleling the Sage Creek anticlinal axis), and local <br />structure, each well has varying amounts of head. The well located furthest <br />from the anticlinal axis (Well GW-42-S2W-2WC) is the well which exhibits the <br />roost head with the amount of head decreasing at the other wells in response to <br />decreased distance to the recharge area. The strata dip so steeply in the <br />area of the Seneca II-W Mine that the maximum amount of head has been observed <br />as 770 feet in the down dip well. This head has also caused artesian surface <br />flow. <br />Ground water flows from the recharge to the discharge, or in this case from <br />the anticlinal axis to the center of the basin. Therefore, the major <br />component of flow appears to be toward the west. <br />Aquifer tests were performed on the two updip wells during the summer of <br />1980. These tests indicate that the Wolf Creek is a fairly well confined <br />aquifer which transmits limited amounts of water. One well was pumped at an <br />average of 1.2 gallons per minute for about 3 1/2 hours, and produced no <br />observable drawdown at an observation well 20 feet away Transmissivity <br />values calculated for the Wolf Creek range from 0.02 Ft~ per day <br />(0.149 gallons per day per foot) for well 3WC, and 0.001 Ft2 per day <br />(0.007 gallons per day per foot) in the two wells tested. Due to the low <br />water yield and transmissivity values the storativity value of the Wolf Creek <br />seam is estimated to be about 1 X 10-x. These values, both transmissivity <br />and storativity, would appear to be quite low. Aquifer test data, however, <br />does substantiate these values. Due to the highly lenticular and <br />discontinuous nature of the Mesaverde Group, it is thought that transmissivity <br />and storativity will be aerially variable. <br />The quality of Wolf Creek coal water is slightly acidic, very hard and saline. <br />Based on data presented, the water type changes from calcium/sulfate to <br />sodium/bicarbonate down gradient. Total dissolved solids (TDS) values exceed <br />U.S. Environmental Protection Agency (EPA) drinking water standards at all <br />three Wolf Creek wells at various sample times. TDS criteria for livestock <br />use has been met at all wells, while its use as irrigation water is marginal <br />due to adverse effects on many crops. These criteria also have been <br />established by the EPA. <br />As previously stated, Well 2WC is located down gradient, and has the lowest <br />levels of TDS and sulfate, indicating that the sulfate is being precipitated <br />from the water as it moves down gradient. <br />Well 3WC displayed the only case of elevated iron levels within the Wolf Creek <br />coal. <br />- 13 - <br />