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CONCLUSIONS <br />The site is suitable for the construction of the proposed treatment ponds. Based on our calculations, the ponds <br />have been designed with adequate capacity [o handle the discharge from the dewa[ering borehole, as well as [be <br />inflow entering the pond as a result of a 10 year, 24hour precipitation event. <br />This report has been prepared to summazize the data obtained and to present our conclusions and <br />recommendations based on the proposed construction and the subsurface conditions a[ the site. Design <br />parameters and a discussion of geotechnical and hydrologic engineering considerations related to construction <br />of the proposed ponds and embankments are included. <br />PROPOSED CONSTRUCTION <br />The proposed project will consist of the construction of two treatment ponds in the Eastern Mining District of <br />the Foidel Creek Mine. The ponds will be situated in the SE 1/4 of the SW 1/4 of Section 21, Township 5 <br />North, Range 86 Wes[ in Rau[[ County, Colorado. <br />It is our understanding that the ponds will be constructed for temporary impoundment of the water being <br />pumped from [he dewatering borehole. The ponds will consist of cu[ and fill construction with the west ends of <br />• the ponds being cut into [he adjacent ridgeline and the eastern ends of the ponds will consist of compacted <br />earthen embankments. Approximately 2780 cubic yards of fdl and 9110 cubic yards of cu[ will be requ'ved for <br />the construction of the ponds. The elevation of [he bottom of the ponds will be 6873.0' and [he elevation of the <br />top of the dams will be 6831.0'. The width of the dam crest will be 15 Feet and the cut and fill slopes along the <br />exterior of the embankments will be constructed to a 2 (horizontal) to 1 (vertical) slope configuration. <br />Whereas, the interior embankJnent slopes will be constructed to 3 (horizontal) to 1 (vertical) slope <br />configuration. The ponds will be constructed with the configurations shown in Figure #1. <br />Each of the ponds will have approximately 2.96 acre-feet of storage capacity when filled to the primary spillway <br />elevation of 6829.0'. The primary spillway for the ponds will consist of an 8-inch I.D. HDPE pipe. The 8-inch <br />discharge pipe will extend approximately 700 feet to the east and northeast, where i[ will discharge into a <br />drainage which flows to Foidel Creek. An emergency spillway will also be placed in each of the cells. The <br />emergency spillway will consist of a 6-inch I.D. HDPE pipe which will be set at an invert elevation of 6830.0'. <br />The emergency spillways will discharge into the borrow ditch located along the edge of the access road, <br />approximately 100 [0 200 fee[ east of the ponds. Inflow to the ponds will be from a 6-inch I.D. HDPE pipe <br />which will generate up to 350 gallons per minute on a periodic basis. <br />SITE CONDITIONS <br />The project site is located north of Routt County Road #33 and within [he permitted lands of the Foidel Creek <br />Mine. The project site is currently vacant and generally vegetated with grasses. <br />• The proposed ponds will be constructed at the eastern edge of a west-east trending ridgeline. The topography <br />of the project site is somewhat variable and generally the proposed pond sites slope down to the northeast, east <br />Job No. 9Cr25T2 Nonhwuc ColoraCO Consultants, Inc. Pagc 1 <br />