PERMFILE73242

• Permit No: M1988112
• IBM Index Class Name: Permit File
• Doc Date: 3/2/1989
• Doc Name: EVALUATION OF FINAL WALL SLOPE STABILITY FOR THE SAN LUIS PROJECT
• Media Type: D
• Archive: No

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5.1 Design Sectors
Figure 11 summarizes the design sectors for the West and East Pit Ore Zones. The delineation is
based upon interpolation of geological contacts as they appear on the ultimate pit limits. The
Biotite Gneiss domain is divided into design sectors exhibiting similar wall trends. Associated with
each mine design sector is a rock fabric assessment and a weak rock mass interpretation as
follows.
6.0 MATERIAL PROPERTIES
The San Luis deposit is primarily comprised of alluvium/Santa Fe conglomerates which is
undedain by altered Pink Granite Gneiss which overlies a clay filled fault. These materials can be
broken by moderate hand pressure (<S5/<i50psi) and require a '~.veak rock mass" design
approach. The Biotite Gneiss is found below the Green Clay Fault and is a moderately hard to
hard rock (>_R3/>_3500 psi). Failure in this material will be controlled by blocks sliding along joints
or a combination of joints.
Definition of the strength properties for the materials comprising the ultimate walls at San Luis
involves:
- the strengths of the intact rock
- [he friction angle for joints in the unaltered rock
- the shear strength for the weak rock mass zones
6.1 Intact Strengths
The unconfined compressive strengths of the unaltered materials have been determined primarily
by point load testing as described in Section 4. The point load test is only valid for the stronger
Biotite Gneiss materials since the weaker materials would crumble upon handling. P summary of
the strengths is given in Table 3.
TABLE 3
UNCONFINED COMPRESSIVE STRENGTHS
Material Unconfined Compressive
Strength Type of Teist
Santa Fe 10 - 80 psi Field Index (375 ft)
Pink Gneiss 10 -150 psi Field Index (92 ft)
Green Clay 10 - 150 psi Field Index (:s1 ft)
Biotite Gneiss 9900 psi Point Load (t38 obs)
( )sample size