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with the largest shear displacement compared to smaller diameter casing. Inclinometer casings were <br />installed approximately 20 feet into bedrock. <br />3.1.3. Piezometers <br />Six (6) vibrating wire piezometers are attached to the inclinometer casings (three each) that were <br />installed along the north edge of haul road HR -1 as shown in Figure 15. These devices are adept at <br />measuring porewater pressures within the slope. High porewater pressures lead to lower shear <br />strengths within the soil and rock, which results in a higher likelihood of slope movement. <br />Three devices are attached to the inclinometer casing at each inclinometer. The depth of the three <br />piezometers were positioned to measure porewater pressure (1) within the colluvium a few feet above <br />the top of the granular drainage blanket material, (2) in the siltstone/mudstone bedrock below the <br />granular drainage blanket material (preferably associated with a coal seam, if present), and (3) within <br />the sandstone or competent bedrock at the bottom of the inclinometer casing. The piezometers were <br />finished using the fully -grouted method. <br />3.1.4 Monitoring Schedule <br />Monitoring will be conducted according to the schedule as follows: <br />A. Survey Mirrors: It is proposed to measure these instruments monthly throughout the year. <br />B. Inclinometers: It is proposed to measure these instruments monthly throughout the year, but bi- <br />weekly readings may be warranted during the spring months when slope movement typically exhibits <br />the highest likelihood. <br />C. Piezometers: It is proposed to measure these instruments monthly throughout the year, but bi- <br />weekly readings may be warranted during the spring months when slope movement typically exhibits <br />the highest likelihood. Piezometer measurements may be taken at the same time the associated <br />inclinometers are being read. Thus, it is recommended to read the piezometers on the same schedule <br />as the inclinometers. <br />Monitoring results will be analyzed for potential movement and elevated porewater pressures. <br />A tension crack in the haul road fill in the vicinity of I12-01was noted in July 2012. This tension <br />crack is believed to have developed at least partially due to the effects of installing the inclinometer. <br />This tension crack, and any other tension crack that is identified along the haul road slide repair will <br />be visually monitored for changes in opening width or length monthly or more frequently. With the <br />P:\Mpls\06 CO\26\06261003 Haul Road Slide Repair\WorkFiles\Report\MCC_Slump_Repair-Instrumentation-Drain Rev 2012-12-12.docx 13 <br />