2020-02-07_REVISION - M1977211 (14)

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1100318 R0T0 0811 JRW1 27 Section 5.2.5 provides details of the groundwater modeling performed using data from these piezometers. Borings EXRW-1, EXAR-4, and EXAR-1 were completed with inclinometer casing at the conclusion of the field investigation for future slope monitoring. The locations of the inclinometers (labeled I-1 through I-3) are shown on the geologic map (Appendix 39). Borings not converted to either piezometers or inclinometers were backfilled and abandoned at the conclusion of the field investigation. 5.2.2.2 Key Field Investigation Observations The April 2011 field investigation provided several pieces of key information and permitted a refinement of the subsequent May field investigation. Key findings of the April subsurface investigation included: Trench TR-1, excavated into the toe of the September 6, 2009 episode of Pikeview Landslide movement (Photograph 18), exposed a deformed green plastic clay bed at the base of the slide debris. This observation indicated the likelihood that a weak stratum in the failed slope likely contributed in some fashion to the slope failures (Photograph 19). Trenches TR-2 and TR-3, excavated on the floor of Area H adjacent to the toe of the December 2, 2008 landslide provided evidence that “overshoot”52 fracturing of the bedrock in this area extended to a depth of between 4 and 5 feet below the floor of the quarry (Photograph 20). This observation provided information on the amount of fractured rock on the floor of the quarry preceding the landslide. Trenches TR-4, TR-5, and TR-6 permitted mapping of the Rampart Range Fault across the top of the quarry face. Borings EXAP-1 through EXAP-3 provided useful information on groundwater conditions and the depth to the top of the Sawatch Formation in 52 “Overshoot” is the result of intentional fracturing of the bedrock during blasting to facilitate the creation of a uniform work surface during aggregate extraction.