2009-02-17_REPORT - M1974004 (2)

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' In the southern expansion area, an east facing temporary wall and a portion of a north ' facing final wall were exposed at the time of our data collections (Photo 6), with data points collected from this mining area included in this report (Figure 2, Stations 3 and 4). ' Factors that contributed to limited exposures being available for data collection included: recent and multiple snowfall events, temporary walls covered by blasting debris that has not yet been removed, and efficient reclamation of exposed walls by Lafarge. 3.2 Slope Geometry An adequate evaluation of the structural geologic conditions of the quarry must also include accurate information regarding the long-term orientations of the pit walls. The wall orientations utilized in this report are based on the current mine plan developed by ' Lafarge West, Inc. in December, 2003 and match the current Colorado Division of Minerals and Geology mine plan (Figure 5). The wall orientations used for this analysis have been the same since the 2004 report. The dip direction and slope angle utilized to ' represent the final quarry walls are presented in Table 1 below. L I j iaaie l: Kepresentative Quarry vran v11=11LauvNIa Quarry Wall Slope Direction of Wall Slope Angle(2) East 242° 45° Northeast 175° 35° * Northwest 151 ° 35° * West 091 ° 45° West 120° 45° Southwest 036° 45° Southwest 016° 45° Southeast 335° 45° Note: 1: Slope orientations are presented as dip directions measured from true north (0°) 2: Slope angles are measured relative to the horizontal. * Based on lower slope angles as recommended from previous studies ' 3.3 Friction Angle Estimation ' In early LF&A annual quarry evaluation reports (L&A, 1997-2002), a total representative angle of friction (? + .') = 40° was used for the wedge stability analysis, where "?" was the basic friction angle and "Pwas the surface roughness angle (Hoek and Bray, 1977). 1 -6-