Laserfiche WebLink
eTber 12, 1979 . <br /> B . Morrison-Knudsen S tu^dv CG �7-101 <br /> i:-u�/ liViY l 1L= l\L.r7V•LRI C.S, 11'P./. - <br /> Coal Basin Nines <br /> • Pitkin County, Colorado <br /> ROCK TLUM SEDUNT & DR MAM CONML STItIJCTURES <br /> The Rock T=ieal is located in Dutch Creek Drainage within Coal Basin <br /> (II-B-App . 7-Att . 4-1) <br /> in Western Pitkin County, Colorado. (Figure 1) The disturbed areas include <br /> the pad area at the portal to the Rock Thiel called the Yard Area and the <br /> (II-B-App . 7-Att . 4-2) <br /> site for placement of waste rock fill called the Waste Pile. (Figure 2) <br /> The Waste Pile area includes the three sedimentation ponds. Undisturbed areas <br /> adjacent to the disturbed areas are isolated from the disturbed areas by div- <br /> ersion ditches. Mine effluent (1 cfs) will be conveyed from the Yard Area to <br /> the sedimentation ponds. <br /> METHODS <br /> Design criteria for the Rock Tunnel site have been developed using U.S. <br /> Soil Conservation Service Methods. References used i.-iclu de; Determination of <br /> Peak Flows within Colorado (1977) , SCS Technical Note 50 and National Engineer- <br /> ing Handbook Number 4. <br /> (Section C) <br /> The calculations are described in detail in the attached appendix. The <br /> attached 2 plates slow design details. (See Exhibit I I-B-Ap p . 5-5&6) <br /> DESIGN <br /> The sediment and drainage control structures include the following: <br /> 1.) Three sedimentation ponds <br /> 2.) Collector ditch <br /> 3.) Ditch Spillway <br /> 4.) Diversion ditches <br /> . 5.) _ Cross-over culvert <br /> i <br /> 3 <br />