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The applicant is approved to dispose of an additional 200,000 cubic yards of waste in <br />the abandoned Eagle No. 9 Mine's Portal Excavation, depicted on Permit Map 25. The <br />details of this disposal plan are presented on Map 28 of the amended permit application, <br />including a detailed site plan and appropriate cross sections. Mining ceased at the No. 9 <br />Mine in 1985. <br />The combined capacities of these two disposal areas represent the refuse generated by <br />the production of 60 million tons of coal, or about 15 to 20 years of mining. <br />The pile has been designed with maximum facial outslopes of 4:1 (horizontal to <br />vertical) and a maximum height of 55 feet. A stability analysis performed by <br />CTL /Thompson, Inc. ascertained a minimum static slope safety factor of 3.6, assuming <br />an angle of internal friction of 42° and cohesion of 0 pounds per square foot. <br />Confirming laboratory testing performed by the applicant determined an angle of <br />internal friction of 42° and a cohesion of 1,500 pounds per square foot. Therefore, the <br />safety factor determination presented within the preliminary stability analysis has <br />proven to be conservative in nature and exceeds the required 1.5 minimum acceptable <br />static slope safety factor required by the regulations. <br />The foundation area of the coal processing waste pile has been prepared by removal of <br />topsoil and unacceptable subsoils and the installation of a gravel and tile 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 standards. <br />A. The Division is proposing to re- approve plans for use, construction, and <br />maintenance of a coal 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 similar 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 a plan /schedule for backfilling 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 />Williams Fork Mines 30 Permit Renewal 06 <br />C- 1981 -044 December 8, 2014 <br />