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<br />c) South Wall <br />Sector III is comprised of Biotite Gneiss material. Stability is controlled by jointing. <br />d) Fast Wall <br />,' Sector IV and V are comprised of Biotite Gneiss materials. Sector IV does not have adverse joint <br />' combinations and therefore the inter-ramp angle is designed at 55°. Sector V requires a 45° slope <br />so as to not undercut potential wedge combinations. <br />' Sector W6 is comprised of Santa Fe material having a design SRMR of 5 - 1596. The slope is <br />designed at 38° for a vertical height of 150 feet. <br />8.0 RECOMMENDATIONS AND CONCLUSIONS <br />It Is recommended that the design angles summarized in Figure 18 be used for tine preliminary <br />'. design of the West and East Pit Ore Zones. The recommended design angles have been derived <br />based on the limited data available from outcrops (East Pit) and a minimal amount of core drilling <br />' (West Pit). The data and assumptions should be checked as soon as the first few benches in each <br />of the design sectors have been mined. It is recommended that the West and East Pks be <br />excavated using 15 ft. high benches. The mining of the interim pits will enable re-evaluation of the <br />final pit slopes to be made as the walls are pushed back to the ultimate. It is believed that triple <br />benching will be required in order [o produce a minimum catchment bench ditch of 25 feet on the <br />55° slopes. The bench face angle will most likely be about 62° 'rf control blasting is not practiced. <br />' Table 9 shows the importance of achieving a steep bench face angle in order to ensure that <br />minimal bench width are maintained with workable slope heights. <br />,' A step out should be implemented at the contact between the weak rock mass and the Biotite <br />Gneiss. <br />' It Is critical for stability that the water table within the slopes be maintained to levels below the pit <br />bottom. This will have to be monitored through a program of piezometers located along the pit <br />' perimeter. A program of horizontal drains will have to be implemented if the well dewatering <br />program as proposed by lialepaska does not achieve the above objective. <br />' Drilling of the south and west wall of the West Pit will have to a conducted during the early <br />production phase of mining. This is required to confirm the weak rock mass strengths that have <br />' been employed for the design of these sectors. <br />The continuity of the structure within the BlotRe Gneiss must be assessed upon mining. This may <br />' result in a steeper overall wall slope'rF instability is restricted to that of bench size. Present design, <br /> <br /> <br />