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' 2.0 Location and Geologic Setting <br />The Spec-Agg Quarry is located to the north of Interstate 70 near Jackson Gulch on the <br />east flank of the Rocky Mountain Front Range, approximately 3 miles south of <br />' downtown Golden (Figure 1). The natural topography of the property increases <br />significantly in elevation to the west, with elevations varying from approximately 6,250 <br />' feet along the eastern boundary to 7,110 feet on the western boundary. <br />' For this investigation, we have defined the quarry consisting of two distinct mining <br />areas: the main pit and the southern expansion area. In past years we accounted for <br />' three regions; in addition to the two mentioned above the middle level in the main pit <br />was also evaluated. This area has almost completely been removed and the remnant of <br />this level is included in the main pit area structural geology evaluation (Figure 2). <br />' At the time of inspection the majority of the floor of the main pit was at an overall <br />elevation 6,325 feet with a remnant of the middle level being excavated along the <br />southeastern margin of the main pit at an approximate elevation of 6,350 feet. Also <br />noted is a second sump located along a deepened portion of the northwestern margin of <br />the main pit that is now at an approximate surface elevation of 6,310 feet (Photo 1). <br />' The southern expansion area is the area of excavation that initiated subsequent to the <br />2003 geotechnical investigation and best estimates of the current elevations of the <br />working benches range in elevation from approximately 6,820 to 6,880 feet (Figure 2). <br />In the southern expansion area the current temporary benches are being advanced to <br />approximately the 6,820 foot elevation (Figure 2) with reclamation occurring in stages <br />following excavation along bench seven (Photo 2). <br />This region of the Rocky Mountain Front Range was formed structurally during the <br />Laramide orogeny in the Late Cretaceous and early Tertiary period. The gneissic <br />bedrock within the quarry is believed to have undergone two to three episodes of <br />' deformation during Precambrian time (Gable, 1968). During this time, the bedrock <br />material was intruded by several distinct igneous bodies and dikes that have been <br />' -2-