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-26- <br />• Benches within the cut slope could be used for stability <br />purposes; they would have to be, however, fairly wide and <br />careful drainage would have to be provided to prevent seepage <br />of surface water into them. <br />The concept of intermediate benches could be successfully <br />used in rock cuts that would be excavated in sound rock, such <br />as rock cuts in sound sandstone ledges in the lower part of <br />the valley. <br />Generally, the width of the toe bench depends on the height <br />and on the slope of the cut. On Plate 5, recommended widths <br />of the catching toe benches for various cut slopes and heights <br />• are presented. These recommended parameters have been frequently <br />used in highway engineering for cuts where rockfall may become a <br />problem. At the Munger Canyon haul road, rockfall is less prob- <br />able than the problem of sloughing from the cut face. The <br />recommended criteria are therefore not directly applicable. <br />We believe that the recommended widths are unnecessarily exces- <br />sive for the proposed haul road and that the width of the catch- <br />ing toe bench could be either reduced or the bench could be <br />totally eliminated. The available width of 14.5 feet (drainage <br />ditch) is sufficient for most recommended cuts as catching space. <br />Periodical maintenance of the ditch would only be required to <br />secure the effectiveness of the drainage ditch. <br />4.5 ROAD FILLS <br />The preliminary design provided to us does not enable <br />