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Ralston Quarry Slope Stability <br /> data, conclusions, opinions, and geotechnical parameters provided herein should not be <br /> construed to be sufficient for other purposes, including the use by any other parties for <br /> any reason not specifically related to the design of the project. Furthermore, the <br /> information provided in this report was based on the exploration and testing methods as <br /> described. Deviations between what was reported herein and the actual surface and/or <br /> subsurface conditions may exist, and in some cases those deviations may be significant. <br /> INTRODUCTION <br /> The project site is underlain generally by bedrock of the Pierre Shale on which residual <br /> (weathered in place) and colluvial ("slope wash") soils have developed. The clay and silt <br /> shales of that formation, however, were intruded by a sill of shoshonite, a dark gray, <br /> igneous rock. <br /> The Asphalt Paving Company has mined aggregate from that shoshonite sill exposed on <br /> the eastern side of a north-trending ridge in Jefferson County north of Golden for several <br /> decades. The mining property straddles the ridge with Ralston Reservoir occupying the <br /> drainage to the west of the mining property and Upper Long Lake immediately to the <br /> east. The relative positions of these features can be seen in an historical Google Earth® <br /> images below. <br /> f' 0. <br /> Retent 1' <br /> Ponds <br /> TzO <br /> AA <br /> Asphalt Paving Co. site Area of Tailings Placed on West-facing Slope <br /> Job No. 19-1235 GROUND Engineering Consultants, Inc. Page 2 <br />