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piles in the original permit application. One pile, the "initial waste rock pile," would <br />contain approximately 1.25 million cubic yards and would be located on the lower <br />facilities bench (the current location of the shop). Subsequent to permit approval, this <br />initial waste rock pile was deleted from MCC's permit. <br />In the fall of 1985, Mountain Coal Company submitted a permit revision application <br />requesting approval of a permanent lower waste pile to be located adjoining the mouth <br />of Sylvester Gulch. This application originally requested approval to permanently <br />dispose of 1.77 million tons of coal processing waste within the proposed structure. The <br />original design phased the refuse pile into five specific design layouts (Phases I through <br />V), including recompaction and reconfiguration of temporarily stored waste material. <br />The pile was constructed according to this original phased design until the Phase IV <br />configuration. A revision application was submitted in November 1992, which <br />eliminated Phase V and reduced the pile to 1.2 million tons. The proposed storage <br />volume represents a 15.7 year life. The proposal included the combination of a 28,500 <br />cubic yard topsoil pile during Phases I through III and a maximum of 45,000 cubic yards <br />of non-toxic soil cover (subsoil) stockpile. Topsoil removed for Phase IV will be stored <br />on the 50-foot bench constructed in Phase III. In addition, an access road was <br />constructed in Phase Three and a portion of the Sylvester Gulch access road to the main <br />fan portal was relocated. Underdrains have been constructed beneath the pile. <br />Piezometric groundwater monitoring will be conducted. Slopes of the pile will be <br />maintained at 2.SH:1V. <br />The November 1992 permit revision application included a slope stability analysis <br />performed in accordance with the slope analysis for the original design in 1985, and for <br />the redesigned pile in 1992. Material strength values were derived from on-site sample <br />testing and nearby previously reported test results. Piezometer observations, falling <br />head parameter tests and analytical projections were completed in order to predict <br />appropriate phreatic surfaces within the proposed waste structure. Data for the 1992 <br />analysis utilized data collected for the 1985 analysis. <br />The applicant has committed to the installation and quarterly monitoring of three sets of <br />survey monuments to monitor slope stability of the waste structure. One row of <br />monuments has been installed parallel to the state highway adjoining the toe of the <br />waste pile on 100-foot intervals. Two additional rows of monuments have been <br />installed perpendicular to the highway on the facial slope of the pile at 50-foot interval <br />spacing. The operator has also committed to quarterly reporting of visual inspections of <br />the topsoil, non-toxic soil cover stockpiles, and refuse pile. <br />For the Lower Refuse Pile, drainage will be controlled by a series of drainage ditches, <br />terraces, and a sedimentation pond. Since the pile will be constructed in phases, the <br />drainage system will also be built in phases. All disturbed area drainage from the <br />topsoil piles, subsoil stockpile and waste pile will be routed to the sedimentation basin <br />at the northwest corner of the lower waste pile (MB-2R). <br />The design incorporates several permanent drainage features into the plan. After final <br />reclamation of the pile, the terraces will be barricaded with rocks or berms to prevent <br />41 <br />