2014-01-30_REPORT - M1973021 - Laserfiche WebLink

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proximity to native ground or zones of sillimanitic gneiss. Sillimanitic gneiss was observed on the north side of the South Quarry and within the bench 6640 highwall. Slope movement was noted on the natural north slope adjacent to the highwall on the 7335 — 7270 haul road. This slope movement appears to be a result of "downhill creep ", typical of steep mountainous terrain that has been increased by proximal mining. Material dislodged in this area could be deposited on the haul road below, and care should be taken when mining in this area and/or when travelling on the haul road below. This area will likely be removed entirely during future mining operations. Minor tension cracks were observed on bench 7160 above the Bench 7120 highwall. These tension cracks appear to be the result of localized highwall movement or settling, as shown on Figure 12, and are not anticipated to cause large scale highwall failure. Failure resulting from the instability will be contained on the bench below. Care should be taken when working on Bench 7150 or below the area immediately below the instability on Bench 7120. Slope instability was noted above Runaway Truck Ramp Highwall 6875, as shown in Figure 17. Care should be taken when working in this area or the area should be stabilized. In areas inspected for the 2013 Geotechnical Addendum, no conditions were observed that could lead to large scale slope failures. There is likely a low probability of large wedge or toppling failures due to the joint and foliation orientation and RMR values observed in the rocks. Additionally, there is likely a low probability of large plane failures along foliation surfaces, that can occur when the foliation surface dips into the highwall face at angles or 38 degrees or greater. There are areas where the unfavorable foliation conditions were observed or where small scale wedge or toppling failures could occur, but the resulting blocks are anticipated to be relatively small and contained on the benches. Most of the unfavorable foliation orientations will likely change during mining operations due to the highly variable nature of the foliation planes, however small scale toppling or wedge conditions are likely to persist during mining. 4.1 North Quarry Observations in the North Quarry on January 21 and January 22, 2014 indicate: • No major failures occurred last year; • Minor, localized sloughing and raveling occurred; • Nearly all rockfall was contained on the benches. Several puncture marks were present on the ice of the reservoir in the quarry, indicating some rockfall into the pond. • Tension cracks present on the reclaimed bench near mine office warrant weekly observation and documentation or slope stabilization. If the condition of the area worsens, engineering consultation is recommended. GEI Consultants, Inc. 24 January 2014 2013 Morrison Quarry Annual Report