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Page C -1 of 4 <br />Appendix C <br />Refuse Pile Expansion East <br />Sampling, Testing, and Monitoring Plan <br />Mountain Coal Company, LLC <br />July 2011 <br />The monitoring plan for the RPE East includes installation of instrumentation to monitor and analyze <br />the following aspects: seepage /groundwater, deformation /stability, and geotechnical properties of <br />refuse material and colluvium. These are relevant aspects associated with the design assumptions <br />used in the geotechnical design and analysis that need to be verified during construction in <br />accordance with the Observational Approach (R.B. Peck, 1969), which is recommended for <br />monitoring the RPE East. The results of the monitoring program will be compared to design <br />parameters established in the permit application and analyses performed as required. The following <br />describes in detail the anticipated monitoring plan of these aspects for the site. <br />Seepage /Groundwater <br />Piezometers will be installed in the RPE East and a weir will be installed near the toe of the buttress <br />to monitor groundwater and seepage. <br />The piezometers will be installed along the centerline of the pile alignment in the intermediate <br />benches in the approximate locations shown on Figure C -1. The piezometer tips will be located <br />within the refuse pile material and in colluvium as shown in the cross section (Figure C -2). It is <br />anticipated that a total of 12 piezometers will be installed. Two piezometer tips will be installed in a <br />single borehole at locations PZ -3, PZ -5, and PZ8. It is anticipated that the piezometers will be <br />installed using the fully - grouted method. The piezometers will be installed as construction of the <br />pile proceeds. Pore - pressure readings will be collected using data loggers and the data will be <br />downloaded quarterly. <br />The weir will be installed near the toe of the buttress as shown on Figure C -1. Flow measurement <br />will be collected at the weir once a month (when not frozen or snow- covered) for the first two years <br />and once quarterly thereafter. <br />Revised July 21, 2011 <br />P:Wpls \06 CO\26 \06261003 RPE E. Penmt Mod Support\WorkFiles \Permit Apphcation\Appendix C Monitoring Plan\App C Monitoring Plan <br />2011 -07 -21 doc <br />