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Getty Task 2 Page 25 March 1, 19 g3 <br />so constant drswdowa msiataiaed on line (ft.), <br />T = transmissivity of the aquifer (sq. ft./day), <br />t =time since drswdowa, so, occnred, and <br />a =agnifer trnasmissivity divided by storativity, T/S (sq, ft./day). <br />The drswdowa imposed oa the line sink is a function of the elevation of the <br />floor of the mice. It wss assumed that the maximum piezometric head measured <br />is the overbnrdea aquifer spprozimates the head is the underlying aquifer. <br />i The piezametric head in the underlying sgnifer was therefore assumed to be <br />approximately 7200 feet. The value of drswdowa is Equation 7 is the <br />difference is this value and the elevation of floor of the mine at the <br />location where the mine intercepts the fracture zone. It was also necessary <br />7 to estimate the treasmissivity and storage coefficient of the underlying <br />f aquifer. Because it was ass®ed that the supplying aquifer occurs in the <br />i Tzont Creek Sandstone, the treasmissivity is probably larger than that <br />~ measured is the overbnrdea agnifer. The sssnmed trsasmissivity utilized is I <br />f Egnaiioa 7 was 100 sq. ft. per dsy which is somerhat larger thaw values of <br />1 traasmissivity of the Tweatymile Sandstone as measured by others. Because the <br />iii <br />Trout Creek Sandstone and Tweatymile Sandstone are similar, 100 sq. ft, per <br />day represents our best estimate of the transmissivity of the Trout Creek <br />Sandstone. An assumed storage coefficient of 0.0001 was also utilized is the <br />calculation. Inherent assumptions is this analysis are that the underlying <br />I <br />supply aquifer is homogenous, isotropic, infinite is extent, sad the initial <br />piezometric surface is horizontal. More importantly, the vertical <br />i permeability of the materiels between aquifers is also assumed to be infinite, 5 <br />n <br />~ <br />i.e. completely open fissures that do not restrict the flow is nay manner. G~% ~ <br />Equation 7 sccoants for inflow to only <br />oae side of the line sink so it is `''0 ` <br />_ l:t <br />~' ' <br />aeceasary_to_multiply the re_snlt_s by two to obtaia,the_flo_w from both sides. ~ <br />L Ia addition, the result needs to be multiplied by the length of the sink to ~ ~~f <br />.. <br /> `` <br />obtain the total inflow. The fracture xoae was assumed to exist at the fault ~ii i~ <br />zone that eats scrosa the main entry approximately 2100 feet north from the ~, - t• <br />+ <br />L ' <br />L <br />entry. At this location, the elevation of the cool is approximately 6550 feet <br />and the drawdo.a that would occur is 650 feet. The length of the xoae <br />a.t_this ,i~d <br />_ <br />I location is S00 feet sad it was assumed the[ the _w idth of the zone is__50 feet. ~' ~ <br />'Ihe total length of the inflow surface is, therefore,.) 100 fee <br />. The use of <br />t ~;,,L " <br />_ <br />_ <br />_ <br />Equation 7 ss described above accounts only for one dimensional flow from the ~ • <br />`~ <br />