2008-11-26_PERMIT FILE - M2008080 (7)

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I - INTRODUCTION Journey Ventures, LLC (JV) proposes to mine the property located approximately one mile northwest of Kersey, Colorado. More specifically the property is located in the Southeast % and the Southeast % of the Northeast'/ of Section 7, Township 5 North, Range 64 West, Sixth P.M. in Weld County, Colorado. The property is bounded by private property on the north, and west, Weld County Road 51 on the east, and private property and Weld County Road 58 on the south. United States Highway 34 is approximately one mile south of the subject property. The proposed mining operation will extract gravel reserves from locations adjacent to man-made structures. The rules and regulations of the Division of Reclamation, Mining and Safety (DRMS) require that any mining within a setback of 200 feet of a man-made structure show thorough engineering analysis that the proposed mining will not cause damage. The accepted method of demonstrating this is through a slope stability analysis. This report contains an overview of the prior geotechnical gravel investigations by Terracon Consultants (TC) and J.A. Cesare & Associates (JAC), and methodology used in the analysis of the mining slopes and their estimated affects on the adjacent man-made structures. Recommendations regarding acceptable setbacks from man-made structures have also been included. II - OVERVIEW JV proposes that the property will be mined in phases until the entire site is mined. The future use for this property is expected to be a lined water storage reservoir. The lining will be done using a perimeter slurry wall that is keyed into the underlying bedrock. The mined and reclaimed slopes will be the same, with a 3h:1v embankment down to an elevation 10 feet below the expected reservoir water surface, and 2h:1v embankment from that point down to the reservoir/pit bottom. Portions of the south and west mining/reclaimed slopes will contain a horizontal bench located 3 feet above the expected water surface to facilitate the construction of the slurry wall. The reservoir will cover an estimated 57 surface acres when full. Actual surface area will depend on the final configuration of the reservoir after reclamation is complete. III - GEOTECHNICAL DATA Geotechnical gravel investigations for the property have been performed by TC and JAC. J&T Consulting, Inc. (JT) estimated soil strength parameters based on the information from the TC and JAC reports, and other stability analyses that have been performed on gravel mining operations located in similar soils. Table 1 represents a summary of the soil strength parameters that were used in this stability analysis. Table 1 - Soil Properties Description Max dry density c Saturated Density c Cohesion s Internal Friction Angle Overburden 110 131 150 22 Sand and Gravel 110 125 0 35 Weathered Bedrock 125 141 100 18 Stable Bedrock 125 141 2000 20 Journey Ventures, LLC - Kersey Gravel Pit Slope Stability Analysis Page 1