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.~ ,, _ .. <br />Sub-base preparation of the existing road was not unlike that <br />• proposed for future work, and described later in this section. The <br />preparation involved the use of a steel roller applied following <br />deposition of material in 8" lifts. Water was added during the <br />preparation work in an attempt to maintain optimum moistuce content <br />of 12 percent. <br />Pit run gravel and crushed grav:~l surfacing was applied to improve <br />the road surface. Fugitive dust suppression will continue to be <br />provided by watering during nonfreezing weather until paving of the <br />road is completed. Fugitive dust controls are addressed in more <br />detail later in this section. Minor realignment, widening and <br />paving will upgrade this feature for use as a haul road. <br />Realignment will be as consistent with topography as possible while <br />maintaining design for its intended use. Overall grade for the road <br />is 5.5X with a maximum pitch grade of 7.5X. <br />Due to the rugged topography and different geotechnical units in <br />which road cuts will be made, several cut configurations may be <br />used. These configurations are summarized in Table 2.2-2 and shown <br />on Figure 2.2-24. Cut configurations were based on a study <br />performed by Geo-Hydro Consulting, Inc. whose report is found in <br />Appendix 0. Stability analysis performed by GVC is detailed below. <br />Generally, the road was constructed by removing colluvial and/or <br />alluvial material from bedrock to attain a width of at least 20 <br />. feet. Long term mining plans call for increased traffic on this <br />road. Since the cuts are steep and the road is sinuous, production <br />and safety needs will best be served if this road is upgraded. The <br />upgraded road will closely follow the existing alignment, but cuts <br />will be stabilized and some curves straightened. <br />Geo-Hydro's report concluded that cut slopes under 60 feet would <br />generally be safe, as evidenced by the existing road cuts. Those <br />cuts over 60 feet high should be analyzed separately. Three of the <br />design cuts did exceed 60 feet in height. Therefore, additional <br />data was collected on these cuts. The additional data gave <br />subsurface structure and soil chara~;teristics for the areas in <br />question. Additionally, we assumed (and analysis confirms) that the <br />existing landform and haulroad cuts have a safety factor near 1.0, <br />see Tables 2.2-3 through 2.2-5. Although no major slides have <br />occurred, the present access and haul road is marginally stable. <br />All design cuts are intended to provide additional-sfab"ility over <br />the existing haul road cuts. <br />Widening and straightening of the existing road will also facilitate <br />surface water handling with a more uniform alignment and catching <br />bench at the toe of cut slopes. This will minimize the possibility <br />of saturating fills and creating downslope stability problems. <br /> <br />M [i <br />RN -~ <br />~ ;`'0:'93 <br />