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M03107GE <br />to provide a drained slope condition. We are available to discuss <br />this with you. <br />Our stability analysis of the proposed Coal Processing Facility <br />site cut slope also included imposing a theoretical load of a <br />loaded haul truck on the haul road roadway located at the top of <br />the proposed cut slope. Our analysis assumed an 80,000 pound truck <br />load with the load equally distributed on each axle. Our stability <br />analysis indicated a theoretical calculated factor of safety of the <br />proposed cut slope with a truck load imposed on the top of the <br />slope of 1.300. The results of our Coal Processing Facility site <br />cut slope stability analysis are presented on Figures 3 and 4. <br />Our stability analysis of the proposed stockpile area and haul <br />road fill indicated a theoretical calculated factor of safety of <br />1.996 for a fill slope inclination of two (2) to one (1) for a <br />slope height of thirty-five (35). The proposed fill slope stabil- <br />ity analysis assumed that the fill would be drained and pore <br />pressures would not develop in the fill. The fill slope stability <br />analysis is presented on Figures 5 and 6. <br />4.0 FILL CONSTRUCTION CONSIDERATIONS <br />All areas to receive fill should be stripped of all vegetation, <br />organic soils and other deleterious material prior to fill place- <br />ment. Areas to receive fill should be constructed with a toe key <br />and benched into competent foundation material. The key and bench <br />concept is shown on Figure 7. We should observe the key and bench <br />preparation to verify that the key and bench extends into competent <br />material. We suggest that construction of the material storage <br />area/haul road fills include a toe drain installed near the toe of <br />the fill and graded to discharge downhill from and away from the <br />fill. The drain may consist of a perforated pipe surrounded by <br />about four (4) to six (6) cubic feet per linear foot of pipe of <br />free draining ASTM C-33 concrete sand. We are available to discuss <br />this with you. The drain should be graded to drain to positive <br />gravity outlets. The outlets should be maintained to prevent them <br />from becoming frozen or plugged and equipped with guards to prevent <br />access by rodents or other animals. The drain system concept is <br />shown on Figure 7. <br />The fill material should be moisture conditioned to about two (2) <br />percent wet of optimum moisture content placed in thin lifts and' <br />compacted to at least ninety (90) percent of the maximum dry <br />density as defined by ASTM D1557, modified moisture-density rela- <br />tionship (Proctor) test. If the compaction equipment used for <br />compaction of the fill has sufficient energy to compact thicker <br />6 <br />• <br />• <br />• <br />~Lam6ert ana ~,soociates <br />GONSULiING GEOTEGN NIOII ENGIN EERS INO <br />MITE HIhL 1ESTING <br />