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final slope -2.5 to 1 (i .e. horizontal to vertical ) and the material used <br /> �. should be compacted to 95% of Proctor Density ASTM D-1557 when placed. <br /> 3. Relocate the highway to the south and construct an entire new <br /> embankment structure in front of the existing embankment utilizing the existing <br /> highway as a toe dam. If this alternative is chosen, the downstream <br /> method of tailings placement should be utilized. The sand tailings should <br /> be separated by use of a "cyclone" for continuing construction of the <br /> toe embankment. See Figure 5 for a cross-section of an idealized downstream <br /> configuration. If this alternative is chosen, it is essential that the <br /> compaction of the "toe dam" (i .e. existing highway embankment) be verified <br /> prior to tailings placement. If necessary the portion of the highway bordering <br /> the existing pond could be moved and used to complete the toe dam along the <br /> extension of pond 3 (i .e. in the vicinity of holes 1 and 2). If suitable, <br /> the material involved with the historic pond could be used for embankment <br /> for the highway relocation. New materials placed as the toe dams should be <br /> compacted to a minimum of 95% of Proctor Density ASTM D-1557. Sand tailings <br /> Q <br /> placed for construction of embankment material should also be compacted to <br /> this density. <br /> With the alternatives listed above, it is essential that a toe drain <br /> consisting of a permeable gravel blanket be installed beneath newly placed <br /> materials for adequate drainage. <br /> If the above measures are not feasible at this time, and a new tailings <br /> site is chosen, certain precautions should be taken after abandonment of <br /> pond #3 for continued stability and protection. The recommendations include <br /> the following but should not be limited to these: <br /> -8- <br />