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Part of the slope stability analyses included interpretation of rock mass classification and, therefore, strength properties. Summaries of estimated rock mass properties based on rock mass classification schemes (RQD, RMR and Q)°, as well as on general rock mass type summaries that were used in the analyses are also included in Attachment D. It is important to note that our analyses were based on the rock mass exposures available for viewing in the quarry during July 2004 and the assumptions detailed in this report. Quarry development should occur as an observational approach whereby initial observations and assumptions aze verified periodically during final highwall development and possible adjustments made if future observations reveal conditions significantly different than those assumed to begin with. It is recommended that the operator make and document such periodic observations, either with their own qualified forces, or by retaining a qualified geotechnical practitioner. Should future exposures reveal differing conditions than those described herein, Brierley should be provided the opportunity to verify our analyses, conclusions and recommendations at that time. CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations aze provided to summarize the discussions included in this report: 1. The site is underlain by a thin veneer of hillside colluvium (up to several feet), which is in turn underlain by metamorphic rocks varying from schist to granitic gneiss. 2. General geologic structure mapped near the quarry includes north to northwesterly striking, easterly to northeasterly dipping foliation and metamorphic compositional layering generally parallel to the foliation. Dips are shallow to moderately steeply dipping, and generally into the hillside at the quarry site. 3. Pre-mining slopes at the site were closer to approximately 2:1 than 2.5:1 as reported in the Fox report. The cut slope along the west side of U.S. 285 across the highway from the quarry is approximately 1:1 overall, and steeper in the lower cut face. Historic mined and reclaimed slopes by others at the site aze as steep as 1:2 and appear to be generally stable. 4. There is an upper weathered bedrock zone in which moderately severely weathered to completely weathered bedrock extends approximately 15 to 20 ft into the rock mass. 5. There aze no known or suspected sites of special geologic interest (e.g., fossil beds) at this site. 6. The quarry is located in an area well outside any existing Geologic Hazard Overlay District Zoning Maps. There is no evidence at the site of slope failure, landslide areas or subsidence. Rockfall areas exist as part of the active mining operation within areas that will be completely mined out before establishing final benches and highwalls. ' Rack Classificatiou Systems for Engineering Purposes; Louis Kirkaldie, Editor; ASTM STP 984; 1988.