_GENERAL DOCUMENTS - C1981017 (240)

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OBSERVATIONS Geotechnical Report - The above mentioned Geo-Hydro report addressed the bedrock and surficial geology landslides and avalanches, and methods of road construction and slope angles. The report noted that: - Development of the haul road system in Coal Basin was a difficult task. With rugged mountainous topography, steep slopes, severe erosion problems, potentially unstable slopes and high avalanche danger comprise a set of exceptionally unfavorable factors for road construction. - Morphological features of the area have been very much influenced by the harsh climate related to the exceptionally high altitude. Erosional processes significantly contributed to the rugged topography. Frequent avalanches continuously modify the surface features at numerous locations along the haul roads at several mine benches. Geo-Hydro found that high soil cuts have been excavated in many road sections, with some grades exceeding 45 degrees, and that "the access to it (the slope of the cut) is difficult or impossible". The report also states that high rock cuts can also be found along some road segments and are typically very steep, frequently up to vertical ; although, again, ". . . access to the slopes is practically impossible" . Geo-Hydro's report goes on to provide very detailed information on the geotechnical aspects of the haul roads. Table 11 (Figure 2) in their report summarizes the configurations and geotechnical conditions of the haul roads. The overall stability of the cut and fill sections of the haul roads is summarized as shown below: Minor or No Moderate Important Stability Problems Stability Problem Stability Problems Cut - 60% 2-3% 17% Fill - 6Z1 131 4`!. All of the important stability problems identified on the haul roads have, for the most part, been attributed to factors other than the existence of the haul roads. These other factors include natural erosional process, avalanches and natural slumping and creeping of steep slopes. A small percentage of the important stability problem areas of the road system may be due in part to the combined effects of natural processes and the existence of the haul road. However, this percentage is very small and for the most part is insignificant.