Laserfiche WebLink
• <br />Appendix 11(5) <br />Safety Factor Analysis for Sediment Pond <br />General <br />The soils classification information was obtained from Tom Kalbenbach, Colorado Division of <br />Mining, Reclamation & Safety. This soil classification information was used to help determine <br />average cohesion and internal friction angle values. <br />Safety factors in this report were determined by a rotational shear analysis using the Hoek <br />Method, Hoek & Bray, "Rock slope Engineering ", 1981. This method uses a series of standard <br />charts to determine the safety factor based on a given set of parameters, including slope height, <br />slope angle, soil density, cohesion, and internal friction angle. <br />The following assumptions are used in these calculations: <br />(1) The material forming the slope is assumed to be homogeneous; <br />(2) The shear strength of the material is characterized by a cohesion (c) and a <br />friction angle (0); <br />(3) Failure is assumed to occur on a circular failure surface which passes through <br />• the toe of the slope; <br />(4) A vertical tension crack is assumed to occur in the upper surface of the face <br />of the slope; <br />(5) The location of the tension crack and failure surface are such that the factor of <br />safety of the slope is a minimum for the slope geometry and groundwater <br />conditions considered. <br />The sediment pond is shown on the following drawings: Map King II -007 A, D, G & G. The <br />pond is located near an existing drainage and will be partly incised into the natural ground. The <br />existing channel will be filled and compacted. This newly created area will be used for the <br />storage of topsoil. Undisturbed storm runoff, that would normally pass through this drainage, <br />will be diverted past the sediment pond site by the East Clearwater Ditch. <br />The proposed pond bottom will be at an elevation of 7227 feet and will have an embankment of <br />11 feet. The embankment elevation is scheduled to be at 7238 feet. Embankment slopes within <br />the pond are proposed to be a maximum of 2H:1 V. The exterior of the embankment will beat a <br />slope of 3H:1 V. See Detail A on Map King II -007 G.. <br />The following parameters were used for the sediment pond embankment Factor of Safety <br />• calculations: <br />GCC Energy, LLC. November, 2009 King H Mine <br />