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RULE 2 PERMITS <br />:._w _.__ __v ~_,~ _. <br />..~.___~._.___._._.._ _____ W.~__.____._~~... ~__.__.~~.~~~_._~~_y~~v______ <br />To evaluate the possible effects of infiltration from the pit areas, a velocity calculation for average <br />goundwater flow can be performed. The calculation is based upon the parameters determined for the <br />Williams Fork Formation as discussed above. <br />Seepage velocity (vs), the true velocity representing the rate the groundwater flows through the pore <br />spaces can be calculated utilizing the following formula (Fetter 2001): <br />vs = Kdh/nedl <br />where: <br />• K is the hydraulic conductivity, <br />• dh is the vertical difference in goundwater elevations between two points, and <br />• ne is the effective porosity, and dl is the distance between the two points. <br />Although the strata between the pit and the creek aze discontinuous, the elevation difference between the <br />pit aquifer and Good Spring Creek (500 feet) and the horizontal distance between the edge of the pit and <br />Good Spring Creek (3000 feet) will be used. The gadient would approximate the dip of the lithology in <br />the area. Assuming an effective porosity of 0.15, with an average hydraulic conductivity of 1 ft/d for the <br />Williams Fork Formation, then: <br />vs = (1 ft/d) (500 ft) / (0.15) (3,000 ft) <br />vs = 1.1 I ft/d <br />The average groundwater velocity of outflow from the South Taylor pit is calculated to be 1.11 ft/d, with <br />the flow presumed to be predominantly in a southeasterly direction following the dip of the southeast <br />dipping leg of the small anticline (refer to Map 7). Thus, the first pit outflow through the bedrock strata <br />would take about 2700 days or about 7 years to flow from the pit to the creek. <br /> <br />SoutA TaylorQ.ower Wilson- Rule 2, Page 117 Revision Date: 3/30/07 <br />Revision No.: PR-02 <br />