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RECEIVED <br />April 2l, 1997 <br />APR 2 31991 <br />Mr. Kent Gorham <br />Colorado Division of Minerals and Geology Division of Minerals a ueoioyy <br />1313 Sherman, Room 215 <br />Denver, CO 80203 <br />Subject: Golden Eagle Mine, C-81-013, Technical Revision 43 <br />Dear Mr. Gorham: <br />Basin Resources requested that Greystone develop a Small Area Exemption (SAE) <br />demonstration for [he proposed Golden Eagle topsoil borrow area. This analysis quantified the <br />runoff and soil loss anticipated from the topsoil borrow area from a 10-year 24-hour storm <br />event. The topsoil contained in the borrow area is derived from Noden loam (M11D), a <br />hydrologic type B. <br />The SAE utilized four sediment control features to minimize the Peak Settleable <br />Concentration. Contour furrows will be installed at 25' intervals down the slope with a ripper. <br />Two lines of check dams (straw bales) will be placed at mid-slope and at the base of the <br />borrow area. The area will be mulched at 2 tons/acre. A grass filter exists at the base of the <br />slope's drainage. The resulting Peak Settleable Concentration was 0.44 ml/I from a total <br />contributing drainage area of 7.1 acres. Three sets of supplemental pages for Volume 4 of the <br />Golden Eagle permit application are provided for insertion. <br />Please do not hesitate [o call if you have any questions. <br />Sincerely, <br />~ ~G <br />(~ ~ ? ~ <br />Cathy Begej <br />Hydrologist, Greystone <br />cc. Ron Thompson, Basin Resources, Inc. <br />Enclosures <br />~%''l~ <br />C,~~I ~ <br />~~~a ~ <br />~~ <br />5990 Greenwood Plaza Blvd. Suite 250 Englewood, CO 80111 <br />