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Open standpipe piezometers were installed in boreholes B -3 and B -7. At B -3, the standpipe was <br />screened from 89 -99 feet in depth to measure deep water levels within the bedrock. The B -7 <br />standpipe was screened from 12.5 to 22.5 feet below ground surface. <br />Inclinometer casing was installed in the following boreholes: B -4, B -5, and B -8. The purpose of the <br />inclinometers was to measure any slope movement within the colluvium. The depths to which the <br />inclinometer casing was installed ranged from 25 to 35 feet. <br />Samples of colluvium were collected on August 27, 2010, while stripping colluvium during <br />construction of the buttress. These bucket samples were shipped to Soil Engineering Testing for <br />analysis. <br />MCC's coal preparation plant (CPP) generates coal refuse material that will be placed in the RPE <br />East refuse pile. The CPP processing produces a refuse that is coarser than some previously <br />available refuse materials on site. Refuse material from the initial operation of the CPP was placed <br />and compacted in the existing Refuse Pile Expansion (RPE) area. Samples of this material from the <br />RPE were collected on January 4, 2011. Four representative samples (each sample consisting of a 5- <br />gallon bucket) were collected from the upper 18 inches at various locations. After sample collection, <br />photographs were taken of the sample to document the overall gradation of the material. The coarser <br />material, diameter greater than 3 inches, was then separated from the sample and placed in a separate <br />container. Both sample containers were weighed to determine a total sample weight, and the weights <br />of the coarse and fine fractions. The coarse sample fraction was placed back in the refuse pile while <br />the fine sample fraction was shipped to Soil Engineering Testing for analysis. <br />2.2 Geotechnical Analysis and Design <br />Two types of stability analyses are typically performed for dams and slopes: the Undrained Strength <br />Stability Analysis (USSA) and the Effective Stress Stability Analysis (ESSA). The USSA is <br />performed to analyze the case in which loading or unloading is applied rapidly and excess pore water <br />pressures do not have sufficient time to dissipate during shearing. This scenario typically applies to <br />loading from embankment construction, for example, where the loading takes place quickly relative <br />to the permeability of the soils. It is often referred to as the "end -of- construction" case. <br />Revised July 21, 2011 des <br />26 S _� L1 <br />PAMp1s \06 CO \26 \06261003 RPE E Permit Mod Support \WorkFlles \Permit Apphcahon \Text \Exhibit 82 RPEE design 2011 -07 -21 TR 127 doc 4 <br />