2006-08-02_PERMIT FILE - C1980007 ‎(10)‎

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 8/2/2006
• Doc Name: 2nd Revised March 2006
• Section_Exhibit Name: Exhibit 75 SGARE Sylvester Gulch Access Road Expansion Report
• Media Type: D
• Archive: No

• Two additional bore holes were placed at approximately stations 83+00 and 85+00 by
MCC personnel where Sylvester Gulch will be crossed which showed the clay soils
extended to at least 30 feet below the surface.
A seismic refraction study was performed by UMS in April 2003 under the direction of
ESC to obtain depth to bedrock information especially in the areas where soil borings
could not be performed due to weather conditions. Typically the seismic lines were
extended 100 feet either side of the bottom of the drainage. The locations of the seismic
lines are shown in Figures 1 through 6. The complete report of the seismic work can be
found in Appendix D of this report.
A field geologic mapping of the landslides along the proposed route was performed by R
Squared Incorporated in 2004 under the direction of SEI to accurately delineate all
landslides that could directly impact the stability of the proposed road. These landslides
are shown in Figures 1 through 6.
A borrow source investigation to locate suitable borrow material for the construction of
the roadway was performed in December 2004. This work was performed using a small
backhoe supplied by MCC excavating four holes to a depth of approximately seven feet
at the locations shown on Detail Sheet 14 of 15 found in Appendix A of this report. Soil
samples were placed in five gallon buckets and sealed and shipped to GEI for laboratory
testing.
• 5.2 Laboratory Testing
Laboratory testing was performed by GEI in 2003 and 2005 on selected samples obtained
during the drilling program. Tests performed included:
• Moisture Content
• Atteberg Limits
• Consolidation
• Consolidated Undrained Shear Tests with Measured Pore Pressures
• R Value
• Standard Proctor
• Gradation
The results of these tests can be found in Appendix E of this report.
5.3 Slope Stability Analysis
Slope stability analyses were performed on 11 proposed roadway cross sections and at
the proposed borrow site. The geometry of the cross sections were based both on the
geologic profiles obtained during the drilling program and seismic study and the
proposed roadway section. The native soil strength parameters were based upon the
laboratory testing program. The strength of the borrow material was based on tests
• performed on the borrow material recompacted to 95 percent of standard proctor before
they were placed in the shear machine. The strength of the sandstone bedrock was based