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materials. However, if a layer of SOOX fabric or equivalent is placed beneath the gravel sections, the topsoil materials will not need [o be removed. Eastern Dewaterine Borehole Access Road: Bazed on the three test holes advanced along the proposed Eastern Dewatering Borehole Access Road alignment, i[ appears that 1 to Z feet of topsoil exists at the ground surface. The topsoil materials are underlain by clays. Therefore, we recommend that the gravel section to be constructed for this roadway consist of 8 inches of pit run gravels and 4 inches of Clazs VI base course. The new gravel section should be placed on the clays found below the topsoil materials. However, if a layer of SOOX Fabric or equivalent is placed beneath the gravel sections, the topsoil materials will not need to be removed. We also recommend that the fabric be placed in the portions of the roadway which are to be located along edge and over the existing drainages, such az in the viciniry of test hole #22. The subgrade soils in this area are saturated and pump excessively under relatively Gght loadings. Batch Load Out Access Road: We did not advance any test holes along this roadway since the subgrade soils aze exposed in the roadway cuts. The subsoils generally consist of days and highly weathered caystone bedrock; therefore, we recommend that the gravel section to be constructed for this roadway consist of 8 inches of pit run gravek and 4 incites of Class Vf base course. ROAD BASE AND SUBGRADE PREPARATION We recommend that the existing roadways be prooGolled with a heavily loaded truck prior to any gravel placement. Areas which deform excessively under the wheel loads should be removed and stabilized. Areas appearing to be stable should be scarified to a depth of 4 inches, moistened to the optimum moisture content and then recompacted to at least 95% of the maximum modified Proctor density, in accordance with ASTM D1557. Any additional base course or pit run gravels placed on the roadway or any portions of [he roadway where additional gravels are required, should also be compacted [o at least 95% of the maximum modified Proctor density at or near the optimum moisture content. The baze course and subbase gravels should be approved by the soils engineer, prior to placement. We recommend that the road base gravels placed on the roadways meet the requtrements For Clazs V or VI base course in accordance with the Colorado Department of Transportation specifications. In addition, the subbase gravels should meet [he requirements for Clazs I base course. Prior to placing [he gravel sections on the new roadways, we recommend that all of [he topsoil materials be removed and the exposed soils be scarified to a depth of 6 inches, brought [o within 2 percent of the optimum moisture content and [hen be recompacted to at least 95%. DRAINAGE As previously stated, the collection and diversion of surface drainage away from the roadway areas is extremely important for satisfactory performance of the roadway. The design of surface drainage features should be carefully considered to remove all water from all roadway areas. to addition, the maintenance of all drainage structures should be conducted periodically to ensure proper performance. We recommend that the new gravel surface be constructed with a crown or super elevation of at least 2 !ob No. '15-2J31 Northwest Colorado Consultants. Inc. Pagc 7