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-3 - <br />EXISTING TAILINGS EMBANKMENT <br />The existing embankment is approximately 90 <br />feet high at its maximum, with a crest length of approxi- <br />mately 1200 feet and a crest width.of 28 feet. The up- <br />stream slope is 3 horizontal to 1 vertical, and the down- <br />stream slope is 2 horizontal to 1 vertical. The dam is <br />composed of a relatively fine-grained central core, with <br />a granular shell on both the upstream and downstream sides <br />of the core. A chimney and blanket drain are included in <br />the downstream portion of the dam for seepage control. <br />Sandy and gravelly material for the shell and clayey <br />material for the core were obtained from on-site borrow <br />areas. Free -draining, granular materials for the chim- <br />ney and blanket drains were imported. A typical cross <br />section through the embankment is shown on Plate 3, Slone <br />Stability Analyses. <br />FOUNDATION MATERIALS <br />The foundation materials beneath the embank - <br />mens are quite variable and consist of alluvial and re- <br />sidual soils above a highly -weathered and altered bed- <br />rock. The soils are lenticular and range from fairly <br />onrw cs a Moowr_ <br />