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• from native, partially saturated moisture conditions. It is importartt that the project design <br />provides for good surface drainage, and that good surface drainage is maintained after <br />construction. <br />Subgrade Soi]s: The site soils that will form the pavement subgrade are classified as A-6 and <br />A-7-6 in accordance with the American Association of State Highway and Transportation <br />Officials (AASHTO) classification and are considered poor subgmde materials. R'e estimated <br />that the pavement subgrade would have an R-Value of 5 or a CBR of 3 for use in design. <br />Design Traffic: Using Bureau of Mines Information Circular 8758 "Design of Surface Mine <br />Haulage Roads - A Manual," dated 1977, we used wheel loads of 12,000, 25,000 and 40,000 <br />pounds to generate pavement sections for heavy duty pavements. <br />Recommended Pavement Thickness: Two types of pavement were Considered for this project. <br />• Conventional mine haul road design normally calls for a total pavement thickness for each wheel <br />load increment, regardless of the number of passes. Using the design criteria in the Bureau of <br />Mines Circular, we determined the pavement sections for heavy duty pavements as presented <br />in Table A, below. The materials considered for use are: <br />• Surface -Fine Ctvshed Rock, AASHTO M-43, No. 57, CBR > 80 <br />• Bed Course - Coazse Crushed Rock, AASHTO M-43, No. 3, CBR > 80 <br />• Subbase -Pit Run Gravel and Sand, Max. 3-in., CBR >50 <br /> <br />• <br />30 <br />