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I Mayo and Associates, LC <br />~• Q=KIA (1) <br />Where Q =discharge rate (volume/time) <br />K =hydraulic conductivity <br />I =gradient <br />1 A =effective cross-sectional azea <br />Hydraulic conductivity (K) is a measure of the ability of the rock to transmit water. In <br />the case of fracture flow, as occurred in the B Seam and is anticipated in the E Seam, <br />hydraulic conductivity it is difficult to determine. Based monitoring well responses, <br />Mayo and Associates (1998) calculated a transmissivity (T) for the 14HG fault in <br />monitoring well DH-1 as 3.9 x 105 gaUday-ft. The value is relatively large, which is <br />consistent with the high rate of groundwater inflow into the mine. T includes two factors, <br />hydraulic conductivity (K) and saturated thickness (B). Assuming a saturated thickness <br />'• of 450 feet, K would be about 870 gaUday-ft2. However, in a fault damage zone it is <br />difficult to determine B with certainty. <br />The effective cross sectional azea (A) would be the floor azea of the mine opening over <br />the damage zone adjusted for the porosity of the damage zone, which is a function of <br />total open fracture aperhue. In the B Seam workings there appears to be a relationship <br />between the total vertical fault offset and the effective cross-sectional azea. <br />Gradient (I) is proportional to the shut in pressure of the underlying sandstone. <br />From Equation 1 and the above discussion it is evident that initial inflow rates are <br />~~ proportional to the water pressure in the underlying sandstone and appear to be related to <br />Evaluation of Potential Groundwater Inflows 64 February 24, 2004 <br />Associated with E Seam Mining, <br />~ West Elk Mine, Somerset, Colorado <br />