Laserfiche WebLink
-6- <br />angle of internal friction for compacted waste consisting • <br />primarily of overburden spoil would range from 30 to approxi- <br />mately 40 degrees. Some finer materials may remain as a <br />result of the processing. For purposes of stability analysis, <br />we used an angle of internal friction of 25 degrees with no <br />cohesion. In our opinion, this will be a relatively safe <br />value; however, it can be confirmed after the processing plant <br />is in operation and materials are available for testing. <br />8. Our stability analysis indicates that a factor of safety on <br />the order of 2 will be the minimum computed, based on our <br />present estimate of the angle of internal friction. and a slope <br />of 4:1 (hoizontal to vertical). We recommend that the outslope <br />of the pile be constructed at 4:1 for several reasons. In our <br />past experience with the Highway Department and other agencies, <br />we have found that it is passible to operate planting and mowing <br />equipment on slopes of 4:1; however, as the slope steepens, it <br />is becomes very difficult to operate machinery. There is suf- <br />fient area and the total volume of spoil involved is relatively <br />small. For these reasons, if at all possible, we suggest main- <br />taining a maximum outslope of 4:1. The top of the pile should <br />be graded to provide drainage outward over the entire area of <br />the pile in order to reduce the risk of water standing on top <br />of the pile. Based on present plans of production, the maximum <br />height of pile will be on the order of 35 feet. The maximum <br />height may be less, depending upon the amount of volume reduction <br />from compaction and the actual physical characteristics of the <br />waste material. <br />We recommend that a.positive surface drainage ditch system be <br />installed completely around the periphery of the proposed disposal <br />area. Considering the location of the site the chance of infiltra- <br />tion of water from either surface or below-ground sources is <br />very low, provided a reasonable interception system is installed <br />at the time the pile is developed. Considering the small rate of <br />production of the spoil material, it may be desirable to construct <br />the drainage facilities in a stage-manner in order to have sufficient <br />volume of waste materials to develop the desired contours. <br />ADDITIONAL INVESTIGATIONS <br />This investigation was preliminary in nature and limited because of <br />availability of the refuse material. When the plant is in operation, we <br />suggest that sample of the plant produced refuse materials be obtained and <br />~. <br />