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Blasting Impacts and Rock Slope Stability Assessment for Cottonwood Quarry in Grand County, CO <br />1.0 INTRODUCTION AND SCOPE <br />Richard Linke plans to develop a rock quarry in Grand County on land located west of Granby, <br />Colorado. The planned permit area, shown in Figure 1, covers approximately 80 acres of land <br />located adjacent to Grand County Road 55. The land, if developed for aggregate mining and <br />processing would be leased from the landowner (Carl E. Linke Irrevocable Trust). Investigations <br />of nock outcrops on the site indicate that the site contains a significant source of igneous rock (> <br />30,000,000 tons). High-quality construction aggregate in varying sizes, produced from rock at <br />this site, could be provided to area construction markets. The name of this proposed operation is: <br />Cottonwood Quarry. <br />Rock drilling and blasting methods would be used to fragment and loosen rock at the proposed <br />Cottonwood Quarry. Preliminary development of the quarry will require the excavations to build <br />an entry roadway from Grand County Road 55, followed by side -hill excavation work that can <br />establish room for crushing and conveying equipment, a scale house and processed rock <br />stockpiles. <br />The express intent of this report is to: 1) Evaluate all potential impacts of planned rock blasting <br />work at the Cottonwood Quarry site, and 2) provide a preliminary evaluation of the stability of <br />rock slope walls. This professional evaluation report is intended to provide a technical <br />assessment of the environmental impacts of mining and a preliminary opinion about the stability <br />of mined rock slopes. <br />On March 12, 2004, Gordon F. Revey (author) inspected the proposed site of the Cottonwood <br />quarry. Richard Linke of Linke Construction Co.— the Quarry Developer, Stevan O'Brian of <br />Environment, Inc., and Michael S. Kelvin of Gagnon & Hayne Consulting Engineers, Inc. <br />accompanied the author and pointed out where planned excavations would likely occur_ The <br />locations of residential properties, roadways, utilities and other facilities in the area, along with <br />the topography of the site, were also studied during this site visit <br />In order to acquaint the reader with general issues associated with blasting work—like ground <br />vibration, background information about blasting terms and effects, is included in the body of <br />this report. General information is followed by specific evaluations of potential impacts of <br />blasting at the Cottonwood Quarry site. <br />REVEY Associates, Inc. Page 1 April 2004 <br />