Laserfiche WebLink
I' ' <br /> b) East Pit Ore Zone <br /> This pit primarily consists of Biotite Gneiss material, since the materials above and including the <br /> Green Clay have been eroded. <br /> The delineation of these units as they pertain to the ultimate wall configuration is discussed in <br />,' Section 4. <br />The materials overlying the stronger Biotite Gneiss exhibit soil-like properties which must be <br />delineated and evaluated separately in the stability analysis. The sections shown in Figure 5 <br />illustrate the method used to delineate the weak zones. An SRMR (Slope Rock Mass Rating) of <br />' ~, less than 209'u indicates a weak rock mass that is easily broken by handling of the core. This <br />SRMR value will be employed in assessing a characteristic rock mass strength , Section 6.3. The <br />sections were drawn parallel to the recent geotechnical diamond drilling that was performed as <br />part of this study. Appendix II contains the geotechnical logs for D88-61,62,63,64, and 65 <br />The water levels shown on the individual sections. Figure 5, are derived from a hydrological report <br />performed by Halepaska (AugJ88). Tha report shows that water levels are within 100 feet of <br />surtace and flow is from the north to the south-west which generally follows the topography. <br />Annual rainfall within the mine area is approximately 12 inches. It is concluded in the report that <br />the water table can be maintained below the level of current stripping through a well dewatering <br />program. Consequently, the slopes will be considered as dry for purposes of stability analyses. <br />' I 4.0 STRUCTURAL REGIONS <br />A structural domain is defined as a zone exhibiting similar rock fabric and/or strength <br />characteristics and can be considered as a single unit for design . <br />The lithological units, for purposes of design, are: <br />`1 <br />' 1. Santa Fe conglomerates <br />2. Pink Granite Gneiss <br />3. Green Clay <br />4. Biotte Gneiss <br />' The structural domains are shown in Figure 6 as they occur on the ultimate pit slopes. Structural <br />' information, obtained through oriented drilling, enabled domains to be established. This <br />~ information was augmented by reviewing previous core logs/photographs of exploration drill holes <br />_' located along the pit perimeter, Figure 3. The discontinuity orientations were plotted on lower <br />hemisphere Schmidt plats with respect to true north. The individual stereonets shown in Figure 6 <br />were obtained from oriented drill hole data, whereas the pole plot for the East Pit Ore Zone was <br />' determined through surtace mapping. <br /> <br />IJ <br />