2006-12-12_REPORT - M1974004

• Permit No: M1974004
• IBM Index Class Name: REPORT
• Doc Date: 12/12/2006
• Doc Name: 2006 Geotechnical Report
• From: Lafarge North America
• To: DRMS
• Email Name: ACS
• Media Type: D
• Archive: No

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and dip measurements of discontinuities in the quarry have been obtained.
Figure 4 is a stereographic contour plot of all of the data collected since 1997.
A total of 25 datapoints were collected from the main pit area and 49 points were
collected in the middle level of the quarry, along temporarily exposed north
facing highwalls (Figure 2, Station 2). In the southern expansion area, only a two
small east facing temporary walls were exposed at the time of our data collection
(Figure 2, Stations 3 and 4), and 23 points were collected from this mining area.
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 most recent
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
orientations used for this analysis are the same as the 2004 report. The dip
direction and slope angle utilized to represent the final quarry walls are
presented in Table 1 below.
Table 1: Representative Quarry Wall Orientations
Quarry Wall Slope Direction of Wall(,)
' East 242°
Northeast 175°
Northwest 151 °
' West 091 °
West 120°
Southwest 036°
' Southwest 016°
Southeast 335°

Slope Angle (degrees)(2)
45°
35° *
35° *
45°
45°
45°
45°
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
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