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-19- • toward the existing haul road. In our opinion, the natural ma- terials are sufficiently competent in the other areas to preclude the likelihood of a general slope failure. The foundation con- ditions in Area I control slope design. The recommended slopes approach 4:1 in the lower portion of the fill because of foundation conditions. In Area II, two alternative configurations were considered. The initial design envisioned a single large spoil disposal area on the sloping hillside. Limits of the spoil disposal area were generally defined by surrounding mining. The height of fill re- quired was determined based on the volume requirements. In deter- • mining the preliminary design configurations, we assumed an average slope of 3:1 (horizontal to vertical}. We anticipate construction with a series of benches at 50-foot intervals vertically. The benches will be approximately 30 feet wide. Intermediate slopes will be on the order of 2.5:1 (horizontal to vertical). Configura- tion IIA is shown in plan on Fig. 10. An alternative configuration was considered at Area II which involves construction of a valley fill across the existing natural valley, along with a hillside fill on the south slope of the exist- ing valley. In our opinion, the II-B alternative is considerably more stable than the II-A alternative. Considerable natural con- finement is provided in the II-B alternative. Plan view of alternate II-B is presented on Fig. 11. The most likely mode of failure for • the II-B alternative will be a slump at the downstream toe of the