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INTRODUCTION <br />Northern Colorado Constructors, Inc. proposes to mine the property located in the <br />Northeast '/ Section 25, Township 1 North, Range 67 West and Northwest '/ Section <br />30, Township 1 North, Range 66 West of the Sixth P.M. in Weld County, Colorado. The <br />property is bounded by County Road 6 on the north, overhead power lines on the East, <br />an irrigation ditch to the south, and private property with oil and gas structures on the <br />west. State Highway 85 is less than a half of a mile east of the subject property. The <br />proposed mining operation will extract gravel reserves from locations adjacent to man- <br />made structures. The rules and regulations of the Division of Reclamation, Mining, and <br />Safety (DRMS) require that any mining within a 200 foot setback of a man -made <br />structure show thorough engineering analysis that the proposed mining will not cause <br />damage. The accepted method of demonstrating this is through a slope stability <br />analysis. This report contains an overview of the methodology used in the analysis of <br />the mining slopes and their estimated affects on all man -made structures. <br />Recommendations regarding setbacks from man -made structures have been included. <br />OVERVIEW <br />The mining will occur at 3H:1 V slopes. Concurrent reclamation is planned such that the <br />reclamation embankment will be constructed as the mining progresses. The reservoir <br />will cover an estimated 49 surface acres when full. <br />GEOTECHNICAL DATA <br />Slurry wall design drawings were completed by Applegate Group, Inc. and J.A. Cesare <br />and Associates, Inc. Soil strata thicknesses were estimated from the boring log info <br />shown on the slurry wall design drawings. J &T Consulting, Inc. (JT) estimated soil <br />strength parameters based on other stability analyses that JT has performed on gravel <br />mining operations along the front range. Table 1, on the following page, represents a <br />summary of the soil strength parameters that were used in this stability analysis. <br />-- <br />Northern Colorado Constructors, Inc. — Perry Pit <br />i' JXT Consulting, Inc. Slope StabilityAPageiI <br />9 <br />