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APPfiNDIX M viii SAE - 5 <br />SMALL AREA EXfiMPTION # 5 - SAE - 5 <br />MUNGER CANYON MINE FAN AREA SURFACE WATER CONTROLS <br />To control the runoff of water and sediment from the area where the <br />mine fan is located at the Munger Canyon Mine Site, a berm and hay <br />bales were installed. The hay bales were eventually replaced with <br />silt fence to take advantage of its superior performance. The area <br />was been revegetated with grasses and subsequent invasion of shrubs <br />and (orbs has occurred. <br />During 1994 is was discovered that these sedimentation controls <br />were not specifically addressed in the mine permit application. <br />This document will give specific details of the sedimentation <br />control methods and structures. <br />The area is shown on Figure 2.2-4 and is outside of the area that is <br />controlled by SAE - 1. The dimensions of the area are 60 feet long <br />by 20 feet wide. The area is about 1200 square feet. Figure S-3 of <br />Peak Flows in Colorado yields a CN of 73 for Sage-grass with a C <br />soil and cover density of 30%. <br />Table S-3 of Peak Flows in Colorado, Page 53, yields a runoff of <br />0.10 inch for a 10 year 24 hour event of 1.4 inches. The volume of <br />• runoff will then be <br />R = 0.10 x 1200 sgft / 12 = 10 cubic feet <br />This minor amount of runoff will be insignificant in relation to <br />the amount of runoff generated in other areas of the mine site and <br />the runoff from natural areas within the Munger Canyon drainage <br />basin. <br />The runoff generated by any storm event will be passed through a <br />silt fence located on the outslope of the area. Rundff will be <br />routed through the silt fence by using a berm along the outside <br />edge of the area. Additional sedimentation controls may be used to <br />enhance these measures at the operator's discretion. <br />~~ <br />M(viii) - 5 <br />9/23/94 <br />