Laserfiche WebLink
~C <br />cohesion of 1,500 pounds per squaze foot. Therefore, the safety factor determination <br />presented within the preliminary stability analysis has proven to be conservative in <br />nature and exceeds the required 1.5 minimum acceptable static slope safety factor <br />required by the regulations. <br />The foundation area of the coal processing waste pile has been prepazed by removal of <br />topsoil and unacceptable subsoils and the installation of a gravel and the subdrain and <br />peripheral toe drain. These drains will prevent ground water from flowing into the <br />waste material. Waste material will be placed in 24-inch horizontal lifts, compacted to <br />90 percent of the waste material's maximum dry density, as determined utilizing <br />AASHTO testing specification T-99. Compliance with the certified inspection <br />requirements of Rule 4.10.2 will assure compliance with the approved plans and <br />construction standazds. <br />The operator has requested a variance from the 4-foot-thick, non-toxic cover <br />requirements of Rule 4.10.4(4). The resolution of this aspect to the coal processing <br />waste pile's design is stipulated within the vegetation portion of this findings document, <br />Section B.VIII. <br />A. The Division is proposing to approve plans for use, construction, and maintenance <br />of a coat mine waste disposal area (4.10.1(1)). <br />B. The disposal area will be inspected on a regular basis by a qualified professional <br />Specialist under the direction of the professional engineer, experienced in <br />construction of similaz earth and waste structures. Inspection by this person has <br />been approved by the Division as appropriate (4.10.2(1)). <br />VII. Backfilling and Grading <br />Rule 2.05.5 requires aplan/schedule for backfclling and grading in sufficient detail to <br />allow the Division to evaluate the feasibility of the proposed post-mining topography <br />and the required bond estimate. Volumes of material to be moved were presented on <br />Table 63 of the permit application, and the final backfilled topography is depicted on <br />Map 29. <br />The applicant received approval of technical revisions in May of 1486 to extend <br />development work from the No. 5 Mine to the F seam of the No. 6 Mine. The waste <br />rock produced was approved for placement against the existing highwall of the SA <br />Portal. Designs for this development rock placement aze included in Exhibit 40. The <br />total volume approved for placement is 12,000 cubic yards. <br />The applicant will dispose of underground development waste within the existing No. 9 <br />Portal Excavation. These portals have been sealed. The approved Reclamation plan <br />calls for the backfilling of the existing excavated incline. The applicant will utilize the <br />excavation to dispose of waste. Because there would be no elevated embankment, slope <br />stability is not a concern. Minimal ground waters might invade the unencapsulated <br />waste but are projected to produce insignificant amounts of leachate. A monitoring well <br />28 <br />