Laserfiche WebLink
• CONCLUSIONS <br />1) The subsurface conditions encountered across the project site were variable and generally consisted of <br />a layer of topsoil overlying interbedded sands and clays, and sandstone or clays one bedrock to the <br />maximum depth investigated, 29 fee[. <br />2) The site is suitable for the construction of the proposed embankment and pond. Bazed oa our <br />analyses, the proposed embankment design had an overall factor of safety of 134. <br />PURPOSE AND SCOPE OF STUDY <br />This report presents the results of a geotechaical investigation and slope stability analyses for the proposed <br />Pond 011 sedimentation structure to be constructed in the Yoazt Mine area located in [he SE 1/4 of Section 16, <br />Township S North, Range~87 West of the 6th P.M. in Routt County, Colorado. The approximate location of the <br />project site is shown on Figure #1. <br />A field exploration program was conducted to obtain information on subsurface conditions. Material samples <br />obtained during the subsurface investigation were tested in the laboratory to provide data oa the classification <br />and engineering characteristics of the on-site soil and bedrock. The results of the field and laboratory <br />• investigations are presented herein. <br />This report has been prepared to summarize the data obtained and [o present our conclusions and <br />recommendations hazed on the proposed construction and the subsurface conditions encountered. Design <br />parameters and a discussion of geotechnical engineering considerations related to construction of the proposed <br />pond and embankment are included. <br />PROPOSED CONSTRUCTION <br />We understand that the proposed project will consist of [he construction of an earthen embankment and the <br />associated pond for controlling sedimentation from mining disturbance w the Yoast Mine area located <br />approtmately 7500 Feet west of [he project site. Based on the plan provided, it appears that [he embankment <br />will be approximately 240 feet in length, will have a maximum height of approximately 15 to 18 fee[ and a total <br />capacity of approximately 4.5 acre-Fee[ at the emergency spillway elevation. The dam will be constructed with a <br />minimum crest width of 20 Ceet with both the upstream and downstream faces being constructed at 3 <br />(horizontal) : 1 (vertical) slopes. It is anticipated that the embankment materials will be borrowed from the <br />pond excavation located upstream of the proposed embankment or possibly from a designated borrow source <br />located just outside the pond site. The emergency spillway is planned for the east side of the embankment and <br />• a maximum depth of water retained at this elevation is expected to be in the range of 12 to 14 feet. <br />Job No. 97-3000 NotthWes~ Colorado Consultants, fnc. Page ] <br />