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severe erosion problems. Thicker fills have been, in all- <br /> ,� probablity, subject to considerable settlements. They may also <br /> experience potential stability problems (deeper failures) as <br /> can be seen by infrequent tension cracks located close to the <br /> mine bench crests. <br /> The mine benches are located at high elevations, above the <br /> haul roads. The surrounding topography is very rugged. The <br /> erosion and avalanche problems cannot be avoided in such a <br /> harsh environment. <br /> 2. 4 AVALANCHE PROBLEMS <br /> The region which includes Coal Basin is historically an <br /> avalanche-prone area. The steep gullies and cliffed slopes <br /> formed by the sedimentary rocks, combined with the frequent <br /> heavy snowfall common to the region, encourage the development <br /> of unstable snow. <br /> The locations of important avalanche paths in the area of <br /> study were supplied to us by Mid-Continent Resources, Inca <br /> These locations are based on the experience with annually <br /> running snowslides which occasionally interfere with mining <br /> activity. Some zones of lesser avalanche risk are recorded on <br /> the road logs where evidence of limited snowslide activity was <br /> observed . <br /> Most avalanching at lower elevations, below approximately <br /> 10,000 feet, occurs on steep, open hillslopes. Avalanching is <br /> rare below 9, 000 feet elevation. Avalanches at the higher <br /> elevations around the mine benches tend to run down steep <br /> drainage gullies in the cliff-forming Mesaverde Fromation. <br /> Occasional larger gully avalanches have been known to run up to <br /> 1/3 mile or more down steep stream drainages. <br /> 3. 0 HAUL ROADS <br /> 3. 1 DOCUMENTATION OF HAUL ROADS <br /> Complete , detailed documentation of the haul roads is <br /> presented in Appendix A. Each of the eight roads was <br /> individually documented by completing a set of road logs. The <br /> logs summarize the features and details of the road conditions, <br /> located with reference to the road stationing shown on Plates 2 <br /> and 3. All segments of the roads were classified into one of <br /> four construction parameter categories; road in cut only, road <br /> in fill only, road in both cut and fill , and no significant <br /> earthwork. Properties of the cut or fill are detailed for each <br /> continuous segment of cut or fill . Additional properties are <br /> 9 <br /> GEO4(YDRO CONSULTING,INC. <br />