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_~~. Reporting Period November 19, 1997 -December 1, 1997 Page 2 Field Observations, Data Collection, and Ongoing Evaluations A complete inspection was performed by MCC on November 24 and again on December 1 to visually observe and evaluate the stability of slopes within the project area. Data collection efforts continue and evaluation or re-evaluation of specific areas of concern is being performed, as needed. Individual areas are discussed th detail in the following sections. Supporting documentation is attached for your review. Lower Svlvester Gulch Road: The top-of--slope french drains described in previous reports continue to run water and appear to be working effectively. Slopes below the drains are remaining stable, with the exception of some minor bench sloughing near and to the north of I-4B, and some minor cut slope sloughing behveen Stations 21 and 23. Minor seepage continues in a number of locations. Visua] monitoring of this slope will continue. As reported previously, inclinometers I-2 and I-4B are unreadable and replacement inclinometers at these locations are planned. MCC would like to install these replacement inclinometers this month, but our plans are dependent on the weather and the availability of track-mounted drilling equipment. Observations of these slopes will continue. UoDer Svlvester Gulch Road: The beginning of a new surficial slide on the steepened cut slope at approximately Station 76+00 was observed by MCC construction management personnel on November 21. When inspected on November 24, the slope failure consisted of an approximately 70 foot long by 20 foot wide wedge of undisturbed material that was beginning to peel off of the top of the cut, and a 30 foot long crack, located approximately mid-slope, had opened up to the north of the spalling area. By November 26, material had moved down-slope, filling the road ditch and partially spilling into the roadway. This material was removed to topsoil or subsoil piles as appropriate and the ditch was cleared and reopened. When inspected on December 1, a small amount of additional material had moved down-slope, although not of sufficient volume to require re-cleaning of the ditch. The mid- slope crack to the north remained as observed on November 26, and appears to have stabilized for the time being. Inspection of the undisturbed slopes above these areas on December 1 did not reveal additional cracks or indicate the scarp is progressing up slope. MCC will continue to monitor this slope and will take appropriate actions to maintain the ditch and road should additional sloughage occur. Main Embanlattent (F-Wall): A weekly measurement at inclinometer I-l0 was taken on November 19. Movement continues at a slow rate. As reported previously, inclinometer I-9 is no longer readable. Replacement of 1-9 is planned, but an attempt to access the new drill site on November 25 was unsuccessful due to snow and mud. MCC is checking the availability of track-mounted drilling equipment th the hope of replacing this inclinometer in December. Pore pressures continue to remain stable. Monitoring will continue. Dewatering Borehole Road: Minor water seepage continues on the east side cut slope as reported previously. Survey monuments installed above the cut slope and french drain continue to show a very minor northward creep. Monitoring will continue.