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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 downtown <br />Golden (Figure 1). The natural topography of the property increases significantly in <br />elevation to the west, with elevations varying from approximately 6,250 feet along the <br />eastern boundary to 7,110 feet on the western boundary. <br />For this investigation, we have defined the quarry consisting of two distinct mining areas: <br />the main pit and the southern expansion area. In past years we accounted for three <br />regions; in addition to the two mentioned above, the middle level in the main pit was also <br />evaluated. This area has almost completely been removed and the remnant of this level is <br />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 />approximate elevation of 6,325 feet with a remnant of the middle level being excavated <br />along the southeastern margin of the main pit at an approximate elevation of 6,350 feet. <br />Also noted is a second sump located along a deepened portion of the northwestern <br />margin of the main pit that is now at an approximate surface elevation of 6,310 feet (Photo <br />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 6,800 to 6,880 feet (Figure 2). In <br />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 bedrock <br />within the quarry is believed to have undergone two to three episodes of deformation <br />during Precambrian time (Gable, 1968). During this time, the bedrock material was <br />-2- <br />Lachel & Associates <br />A SCHNABFI Fn:GINEFRIt1G'OHPANY