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/ 'ltr~antvmile Coal Comnanv - Cotity Road Relc~c~ri ~„ <br />This report contains the approach, detailed drawings, and backup sheets associated with <br />the design for relocating approximately 3,000 ft of County Road 27 in Routt County, <br />Colorado. The project is located near the surface facilities far the Cyprus-Amax', <br />Twentymiie Coai Company, underground mine. <br />The road is being re-located back to its ofd alignment to mitigate potential rockfall hazards <br />associated with the adjacent Twentymile sandstone cliff. <br />APPROACH <br />Aerial and conventional survey data were used to construct the surface layout plan shown <br />on Drawing 1. The relocation alignment was then selected and a longitudinal profile <br />prepared (lower section on Drawing 1. Subsequent steps included: <br />Establishing the safe stopping distance and computing the crest and sag vertical <br />curves at either end of the relocation alignment. <br />2. Developing sections at intervals along the relocation alignment. <br />3. Developing a longitudinal section far the new road section. <br />4. Evaluating soil conditions. <br />5. Testing soil from borrow areas to establish compaction criteria: by Northwest <br />Colorado Consultants, Inc. (Reference 1). <br />6. Evaluating surface drainage requirements (see Reference 2). <br />DESIGN SUMMARY <br />The design, presented in the attached drawings, tables. and sections, is for approximately <br />3,000 ft of road. The average roadbed width is 48 ft with a 30 ft wide section of 4-inch <br />thick asphalt. Surface drainage wilt typically be accomplished using 2-ft deep, 2:1 (H:~ <br />sloped 'v" ditches. One, 2-ft diameter, 80-ft long culvert will be installed as shown on <br />Drawing 1 to conduct surface water beneath the new road. <br />The following work products have been prepared for input to the planning process: <br />SubTerra. Inc. 1 26~1un-95 <br />