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i~ <br />`•J• Lohman's (1952) formula for nonsteady flow to a well of constant drawdown, <br />i artd (3) McWhorters (1981) methodology for cal culatirtg inflow to mines from <br />I <br />a coal seam. Because Empire Energy has no direct measurements of the <br />hydrologic properties of the coal; estimates have been made. <br />Transmissivity (T) and storativity (5) values for equivalent coal beds at <br />the nearby Northern Coal Kline were obtained (Table 19). Specific yield <br />(Sy) was estimated to be 0.10. Although the coal thickness (b) can vary, <br />an average thickness of 12 feet was used. These values were then applied <br />to the McWhorter method and used to try to duplicate the past measured <br />flows in the No. 9 Mine. The values of T and 5 were varied until a <br />reasonable match to observe flows was obtained. The values of 1 and 5 <br />that produced the best were• 30 ftz/day (225 gpd/ft.) and '0.002 <br />respectively. It was found that the values for transmissivity and <br />storativity used for the No. 9 mine produced a reasonable fit to observed <br />flows in the No. 5 mine as well. These values are 225 gpd/ft and 0.002 <br />respectively. <br />Longwell mining is proposed for portions of the Empire Tract <br />(including most of the Utah Tract). It is not anticipated that longwall <br />mining will produce any more flow per unit area mined than conventional <br />mining methods. In those areas of the No. 5 Mine where comple*_e <br />extraction has been carried out in the past, the inflows are not <br />detectably higher than those adjacent areas that have only been roomed. <br />McWhorter Method - This method assumes that the flow into the mines <br />is a function of the time since mining of each main began (t), the rate of <br />advancement of each main (R), and the length of each main (L). It does <br />(REV. 1/17/84) <br />III-71 <br />