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SEP-9-c''004 15:17 FROM: BILL & JANE JgNKE 1-970-728-6315 <br />70:19702475104 p,7 <br />Michael W. West Geological, Georechnical, Envtronmemat 69705. Holly Clre[e, SWte 206 <br />' and Assoctatts, Inc. and Earthquake Engineering Ceatennlal, CO 80112-]066 <br />Consulting L•nginecrs (720) 529-5300 <br />and Geologists FAX (720) 529-5335 <br />E-MaiL• m-west®gwest.net <br />www.m-west-assoc.com <br />December 23, 2002 <br />Mr. Bill Janke <br />P.O. Box 642 <br />Ophir, CO 81426 <br />SUBJECT: Engineering Review of Pathfinder Embankment Slope Stability <br />Analyses and Phase II Permit Application and Drawings, San Miguel County, <br />Colorado. <br />n?~~ynataz.41 Project No. 02490 <br />Dear Bill: <br />As requested, I have completed my review of recently provided documents <br />including: (1) letter report prepared by Pinnacle Engineering addressed to Buckhom <br />Geotech dated November 25. 2002 presenting recent information from inclinometer <br />and piezometer installation, laboratory testing and slope stability analyses; (2) set of <br />four drawings prepared by Foley Associates, Inc. for Pathfinder Development, Inc. <br />entitled "Pathfinder Gravel Pit Access Road and Phase Ill Construction" with <br />professional engineer stamps dated September 28, 2002; and (3) Pathfinder Phase <br />Iii permit application resubmitted on October 16, 2002. This letter summarizes my <br />review comments which are as follows. <br />The "Relocated Wetlands" will promote infiltration of water into the ground <br />in the area immediately adjacent to and uphill of the recently modified <br />embankment slope. Even with the three feet thickness of relatively low <br />permeability material placed along the "Relocated Wetlands" channel, <br />significant infiltration of water can be expected in this area. Such infiltra- <br />tion zones should b~~ avoided in the vicinity of an embankment slope of <br />questionable stability and of significant importance. <br />2. The "Relocated Wetlands" concept includes excavation of an approximately <br />50 feet high 1.Sh: ] v (horizontal to vertical) cut slope immediately below <br />State Highway 145. Significant erosion can be expected on this cut slope. <br />Material that erodes off the slope will be deposited in the "Relocated <br />Wetlands" channel essentially damming-up the channel and further promot- <br />ing infiltration of water in this area In addition, construction of this cut <br />slope could destabilize the hillside resulting in a slope failure that would <br />take out State Highway 145. Regarding cut slopes; the Uniform Building <br />Code states: <br />"The slope of cut surfaces shall be no steeper than is safe for the <br />intended use and shall be no steeper thnn 1 unit vertical in 2 units <br />