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7. Bedrock exposures at the site primarily reveal foliation jointing subpazallel to <br />metamorphic compositional layering. The foliation strikes northwest and dips <br />from shallow to moderately steeply to the northeast, generally into the hillside <br />that is being mined. Secondary joints that are steeply dipping to subvertical also <br />occur. Finally, tertiary joints exist that dip northwest fo southwest, or generally <br />out of the hillside that is being mined. <br />8. Analysis shows potential slope failures if the slope were steepened to 1:4 from the <br />originally proposed 1:2 configuration, but acceptable slope conditions for a quarry <br />development if steepened to 1:3 as Elk Creek is presently proposing (12 ft <br />benches by 35 ft highwalls = 1:2.9). <br />9. For the proposed 1:3 slopes, our analyses indicate that sliding failure is <br />kinematically admissible only on the westerly dipping joint set, but that this is <br />mechanically admissible only in the upper weathered rock. Toppling failure is <br />not kinematically admissible for any of the six joint sets analyzed. Several wedge <br />failure modes are kinematically and mechanically admissible in the upper <br />weathered rock, but not in the general rock mass. The upper weathered rock <br />should be laid back to 1:1. Limited individual wedge failure in final individual <br />highwalls is usually considered acceptable in quarry operations. <br />LIMITATIONS <br />Brierley Associates prepared this report in a manner consistent with the level of care and <br />skill ordinarily exercised by members of the engineering community currently practicing <br />in Colorado subject to the time limits and physical constraints applicable to this report. <br />No other warranty, express or implied, is made. <br />This report has been prepazed for the specific site, development and purpose described to <br />Brierley by Elk Creek. The data, interpretations and recommendations contained herein <br />pertain to this specific project and are not applicable to any other project or site location. <br />Furthermore, they are for the sole benefit of Elk Creek. No other party may use or rely <br />on this report or any portion thereof for other benefit without the express written <br />pernussion of Brierley. <br />Slope stability evaluations included in this report are based on the referenced data <br />available at this time and on the proposed slope design by Elk Creek. If, during <br />construction, subsurface conditions aze encountered in the future that differ materially <br />from those described in this report, Brierley should be contacted and allowed to review <br />said conditions and reevaluate the conclusions and recommendations provided at this <br />time. If Brierley is requested to provide future assurances about conditions not materially <br />differing from those presently assumed and/or about the stability of final slopes <br />constructed in the future, adequate field review, observation and evaluation by Brierley <br />will be required. <br />Finally, all conclusions and recommendations about slope stability are based on final <br />slope configurations proposed by Elk Creek and assumed to be constructed in a safe <br />manner with the level of Gaze and skill ordinarily exercised by members of the mining <br />