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3.0 Slope Monitoring Instrumentation <br />Slope monitoring instrumentation will be installed as part of the observational approach to slope <br />stability design and monitoring being used for the haul road slide repair and the RPEE facility. This <br />section provides information on instrumentation planned for each area. <br />3.1 Haul Road HR -1 Area <br />This section summarizes instrumentation proposed to monitor the repaired slope along Haul Road <br />HR -1. Slope monitoring will be conducted in the vicinity of the repaired haul road slide area through <br />placement of survey mirrors, inclinometers, and piezometers. These instrumentation types are <br />described in more detail below. <br />3.1.1. Survey Mirrors <br />It is proposed to install 12 survey mirrors along the repaired slope to monitor slope movement as <br />shown in Figure 21. Mirrors are advantageous because they can provide extensive monitoring <br />coverage along the slope and they can provide data for very large displacements without being <br />damaged. The disadvantage is that there is a significant amount of "noise "' in the readings due to <br />temperature and other effects, and they can be impacted by animals, equipment, and other elements. <br />Most of these mirrors will be installed within the original slide mass area, but a few of them will be <br />located outside this area to determine if possible movement is contained within the original slide <br />mass or if it extends outside this area. <br />3.1.2. Inclinometers <br />It is proposed to install two (2) inclinometers along the north edge of haul road HR -1 as shown in <br />Figure 22. Inclinometers are advantageous because they can accurately measure very small <br />displacements and they are less susceptible to disturbance at the ground surface. They also help to <br />identify the depth of the shear surface should movement occur. Disadvantages of inclinometers <br />include the length of time needed to monitor and they can shear off with sufficient subsurface <br />movement, and might become inoperable after several inches of displacement. <br />These inclinometers should be 85 mm (3.34 inches) in diameter. These are the largest diameter <br />inclinometers commonly manufactured. These are recommended because they can remain functional <br />with the largest shear displacement compared to smaller diameter casing. Inclinometer casing should <br />be installed approximately 20 feet into bedrock. <br />P Mpls 06 CO 26 06261003 Haul Road Slide Repair WorkFlles Report MCC_ Slump_ Repair- Instrumentation- DrainRes 2012 -05 -25 docx <br />12 <br />