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~ iiiiiiiuiiiiiiiiii <br />~~ COLORADO P.O. Box 1301 <br />' ~ FZ~NER Rifle, C0 81650 <br />ENGINEERING, INC. Faix99 066 544564 <br />' %d : DW(~ <br />' ~ owc ~ A,~.~~c.a..~ 50~ ~- a ~ R~C~Ii/E® <br />DoG_ Kh~wrB: Cmrts'~'~v~-t<%on RdlOm ~ Pow r~it;er~lon <br />~br St~~M t~~te' R" n APR 21 2000 <br />' Mr. A I len Sorenson Division of Minerals 8 Geology <br />Colorado Department of Minerals & Geology <br />' 1313 Sherman St. Rm 215 <br />Denver, CO. 80203 <br />' RE: American Soda LLP, Yankee Gulch Minerals Project <br />Storm Runoff Pond -Construction Inspection (Permit # M-99-002) <br />Dear Mr. Sorenson <br />' On behalf of Kvaemer Metals, Colorado River Engineering Inc. has completed quality assurance <br />inspection services during the constmction of the storm mnoff retention pond at the American Soda LLP <br />' Yankee Gulch Minerals Project, upper site. The retention pond has been constmcted with an impermeable <br />High Density Polyethylene (HDPE) plastic liner and is designed [o retain srorm runofT collected from the <br />upper plan[ site. We have prepared this letter report to summarize construction observations, testing results, <br />' and as-built documentation. This letter shall serve as certification that the pond has been constmcted in <br />accordance with [he attached design drawings, specifications, and liner installation guidelines. <br />' Attached in Appendix-A are the following design drawings and technical specifications for the <br />project. <br />I. Kvaemer Metals Drawing No. 01-V-008, "Upper Plant Site Storm Retention Pond" <br />2. Kvaetner Metals Drawing No. O1-V-009, "Upper Plant Site Storm Retention Pond, Sections <br />& Details". <br />3. Kvaemer Metals Specifications GC-Ol, "Site Work" <br />' 4. Kvaemer Metals Specifications GC-18, "Geosynthe[ic Lining", Revisions: A-8/19/98, 0- <br />6/3/99 <br />Also included in Appendix-A are the quality assurance manuals provided by the lining manufacturer <br />' (Agra America) and lining installation contractor (Colorado Lining international). <br />Construction Summary <br />' Construction on the stortnwater retention pond began the first week of February 2000. The site was <br />first grabbed with organics and topsoil stockpiled. The top 1't of soils was stripped and stockpiled for future <br />' use as bedding material. The retention pond embankment was constmcted by using excavated material from <br />the eas[em bank and pond Floor for till on the downgradient western bank and on the northern and southern <br />embankments. Additional borrow material was used from the parking area north of the pond. The <br />' embankment material consisted of sandstone rock, fine sands, and tines (silts & clays). The embankment was <br />constructed in 8-inch vertical lifts and compacted using a sheepsfoot vibratory compactor. Moisture content <br />was maintained by application from a water truck. <br />1 <br /> <br />