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MEMORANDUM ht <br /> Adrian Brown <br /> there has always been groundwater flow to the east out of Grassy Valley into Beaver Creek,from the 106 acre <br /> area shown double hatched in Plate 6. <br /> These data have been used to produce pre-mining groundwater contours,which are presented on Plate 6.The <br /> contours honor the pre-mining water level observations, and fall above or at the post-mining water level data <br /> that is presented below. <br /> Consistency of Pre-Mining Groundwater Elevations with Underground Mining <br /> Gold was emplaced in the Cripple Creek diatreme by hydrothermal fluids.These fluids flow most readily, and the <br /> gold dissolved in the fluids emplaces most readily, in high permeability, high porosity locations within the <br /> rockmass. Because of this,the locations of historic underground mining can be used to identify locations with <br /> high permeability, which should correlate with the water table map, with elevated heads expected in areas <br /> where there is no mining (because there is no gold due at least in part to low hydraulic conductivity),and lower <br /> heads expected in areas where there is intense mining(because there is more abundant gold due at least in part <br /> to high hydraulic conductivity). <br /> The locations of underground mining have been recorded since the inception of gold recovery at Cripple Creek, <br /> and these locations are shown on Plate 8.These mines are expected to trace the high permeability locations in <br /> the Cripple Creek mining district. The relationship between the high conductivity locations that were <br /> subsequently mined and groundwater level contours developed using the mine water level data is as expected, <br /> with areas that were mined having low heads(for example the area between the Isabella Mine and Victor <br /> Incline), while areas which are not mined (for example in East Grassy Valley) high heads were observed. <br /> Consistency with Diatreme Geochemistry <br /> The solid-phase geochemistry in the Cripple Creek diatreme provides a record of the location of the <br /> groundwater table before mining(Eary, Runnels,and Esposito, 2003). CC&V has investigated the Cripple Creek <br /> mining district with an extensive drilling and sampling program.To date, a total of approximately 5,252 <br /> boreholes have been drilled,from which approximately 189,450 samples have been taken, logged, and analyzed. <br /> The locations of the sample boreholes are shown in Plate 9. Of these, 169,038 samples have been sampled and <br /> analyzed from the 4,626 bore holes drilled into the diatreme,to which the following analysis is restricted. <br /> Three parameters that are analyzed provide insight into the location of the pre-mining water table or zone of <br /> saturation at the site:total sulfur abundance, total carbon abundance, and degree of oxidation. <br /> Sulfur <br /> Sulfur is present in the Cripple Creek diatreme rockmass predominantly as metal sulfides (primarily pyrite), with <br /> trace to moderate amounts of gypsum and anhydrite (calcium sulfate, variously hydrated).The sulfur is subject <br /> to removal above the water table by two processes: <br /> Page 3 <br /> Adrian Brown Consultants, Inc. <br /> 130 W.4rh Ave.,Denver CO 80223 <br /> 303-698-9080 www.abch2o.com <br />