Laserfiche WebLink
1 <br />1 <br />3 <br />' 3. The geometry of Streeter Canyon is such that the width <br />' of tl~e fill will be about 900 feet at the 6900 fill <br />elevation but only about 450 feet at the toe of the <br />fill. <br />4. The runoff from Streeter Canyon will be channeled into <br />an interceptor ditch constructed along the northern <br />edge of the fill. <br />' 5. The final fill surface will be revegetated. <br />Site Conditions and Current Construction Procedures <br />' In a previous report entitled "Waste Dump Stability Study <br />for Colowyo Coal Company, Craig, Colorado" dated April 1977, <br />Golder Associates evaluated tl~e soil conditions in Streeter <br />Canyon. In general, the upper areas of the canyon and the <br />' canyon walls are underlain by a thin layer of residual soil and <br />weathered rock. In the lower portions of the canyon, a thick <br />' sequence of loose colluvium/alluvium occurs exceeding 75 feet in <br />thickness near tY~e mouth of ttie canyon. These soils are <br />' composed predominantly of loose silty sand witVi varying amounts <br />of gravel. Locally, the deposit includes sandy silts and clayey <br />silts. We estimated that tiie friction angle of the <br />' colluvium/alluvium is about 26° to 30°. <br />According to Colowyo personnel, approximately 8 million <br />yards or 60% of the final fill volume was placed from January <br />' 1977 to May 1978. This material was placed by end dumping in <br />essentially two lifts of 200 feet and 100 feet thick. Figure 1 <br />' shows the approximate fill configuration as of A1ay 1, 1978. The <br />angle of repose of tt~e 200-foot end-dump lift varies from 37° to <br />1 <br />' Golder Associates <br />