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3.3.3 East Panel Landslide Geoteclhnical Evaluation <br />An East Panel landslide occurred on October 8, 2006. A geotechnical evaluation program was <br />designed by Agapito Associates Inc. (AAI). This program was designed to determine the slide <br />plane and to determine parameters for future development of G and K pit. This program also <br />included sites in Z dip pit. <br />A total of three sites were completed with inclinometers, four sites with piezometers and several <br />sites with surface benchmarks. Surface benchmarks are used to monitor changes in down -dip <br />displacements over time_ Data retrieved from inclinometers is deflection of casing as a function <br />of depth below the collar. Plats are developed of deflection versus depth. Piezometers are used <br />to monitor water levels. <br />The monitoring was performed in accordance with the recommendations of Agapito Associates <br />Inc. as described below: <br />• Once per month during the dry season. <br />• Once per week during the wet months of spring (April -May) and fall (September - <br />October). <br />• Once per day after major precipitation (rainstorm) events > 0.50 inches for 3 — 4 days <br />transitioning to weekly for 1 — 2 weeks and back to a normal schedule thereafter. <br />In September of 2008, the required monitoring frequency was reduced (by AAI) to the guidelines <br />shown below: <br />• Once per month <br />• Once per week for two weeks following a major rainstorm even (> 0.5 inches) <br />In October of 2009, the original monitoring program was replaced with a state -of- the -art <br />program that was developed as a part of a new ground control plan submitted to MSHA in <br />advance of resuming mining operations in the land slide area. The monitoring plan was <br />developed with the assistance of AN and Applied Geomechanics. <br />With the new system, three GPS stations were constructed in the slide zone. A fourth station <br />located outside the slide area acts as a reference and repeater station. Four boreholes were <br />drilled. These holes were drilled for instrumentation installation only; no characterization core <br />holes were completed at these sites. Each hole was cased with inclinometer casing. Each <br />borehole contains two fully grouted piezometers and three in -place inclinometers. Each <br />instrumentation station is equipped with audible sirens and strobe light alarm systems, radio <br />equipment, solar panel and batteries. <br />3 -27a <br />ks <br />A proved., <br />