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• • 2. An additional berm of earth could be placed at the toe of the fill embankment to increase the stability. The material used should be compacted at a minimum of 95~ of Proctor Density ASTM 0-1557 when placed. 3. Relocate the highway to the south and construct an entire new ~ ' embankment structure in front of the existing embankment utilizing the existing highway as a toe dam. If this alternative is chosen, the downstream method of tailings placement should be utilized. The sand tailings shoulcl be separated ' by use of a "cyclone" for continuing construction of the toe embankment. See figure 5 for a cross-section of an idealized downstream configuration. ' If this alternative is chosen, it is essential that the compaction of the ' "toe dam" (i. e. existing highway embankment) be verified prior to tailings placement. If necessary the portion of the highway bordering the existing pond could be moved and used to complete the toe dam along the extension of pond 3 (i. e. in the vicinity of holes 1 and 2). If suitable, the me~terial involved with the historic pond could be used for embankment for they ' highway relocation. New materials placed as the toe dams should be compacted to a minimum of 95% of Proctor Density ASTM D-1557. Sand tailings placed ' for construction of embankment material should also be compacted to this ' density. With the alternatives listed above, it is essential that adequate drainage ' be provided beneath any newly placed materials. Drainage provided bpi natural soils may 6e adequate; however, it should be verified by in situ perc:olation~ ' tests. ~~y'~' °~`~ If the above measures are not feasible at this time, and a new tailings site is chosen, certain precautions should be taken after abandonment of pond #3 for continued stability and protection. The recommendations include the following but should not be limited to these: -8-