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2.05.3(3) and 2.05.3(4). Six piezometers have been installed to <br />monitor water levels and quality. Refer to the Proposed Surface <br />Disturbance Map, 2.05.3(2)(b)-1 for their location. <br />Geotechnical work done for the underground development waste <br />disposal area was done by Armstrong Engineering in May, 1980, <br />Appendix B (volume 4 of 6), and by Rocky Mountain Geotechnical, <br />August, 1981, Appendix D (volume 6 of 6). The Armstrong work <br />was to determine the stability of the waste and overburden. The <br />Rocky Mountain Geotechnical work was to analyze the slope stability <br />at the proposed slope of 3.5 h:l v. They found this slope to <br />have a safety factor of 2.402 (page 9, Appendix D). <br />The construction cycle or use of the disposal site will <br />consist of salvaging topsoil, salvaging overburden, and placement <br />of the waste material. Topsoil will be removed between contour <br />elevations determined by the anticipated fill for the next year, <br />approximately 10-15' vertical fill. The topsoil will either be <br />replaced on an area being reclaimed in the disposal site, or be <br />stockpiled in the designated topsoil stockpile area, Map 2.05.3 <br />(2)(b)-1. Refer to Table 2.05.3(5)-1 for the schedule of topsoil <br />removal. As shown on Map 2.05.3(2)(b)-1, a total of 9.00 acres <br />of topsoil is available out of the proposed total disturbance <br />area of 20.28 acres. The total estimated volume of topsoil <br />available is 9.00 acres x 5.3 inches topsoil (Section 2.04.9) x <br />43,560 (square feet per acre) / 12 (inches per foot) / 27 (cubic <br />feet per cubic yard) = 6413 cubic yards. <br />The overburden will be stripped in the same zone as the <br />topsoil to the depth readily available (avoiding rocky, hard <br />material). This overburden will be replaced on final slopes or <br />stockpiled around the disposal site. Drawing 2.05.3(9)-2 shows <br />the anticipated overburden material available over 2' thick. <br />The calculated volume of 80,000 cubic yards of overburden available <br />was determined using the cross sections in Drawing 2.05.3(9)-2 <br />and an estimated 2' depth of overburden available in most of the <br />remaining area to be filled. Overburden west or below the initial <br />fill areas will remain untouched until needed for cover. (Note <br />the area of overburden storage on Map 2.05.3(2)(b)-1.) <br />REVISED November 15. 1983 122 <br />