Laserfiche WebLink
III illlllllillll III <br />999 <br />Panorama Resource Services, Inc. <br />4660 E. 115th Circle <br />Thornton, Colorado 80233 <br />June 11, 1984 <br />RECEIVED <br />Susan Mowry <br />Mined Land Reclamation JUN 13 19b~ <br />1313 Sherman Street <br />Denver, Colorado 80203 MINED LAND RECLAMATION DIVISION <br />Colo. Dept of Natural Resources <br />Dear Susan: <br />Enclosed are some details concerning the truck unloading facility proposed <br />for the Animas Mine. A culvert will be placed in diversion ditch #1, to <br />handle the peak flow determined in the Animas Mine Permit. <br />As shown on the enclosed sketch, the truck turnaround will be placed where <br />the existing storage area is located near the explosive magazine. All <br />material near the truck path will be cleared out and moved to the lower <br />part of the Animas Mine disturbed area. A 1 ft. berm will be placed along <br />the south edge of the road to prevent road runoff from entering the diversion. <br />All disturbed runoff will travel over the diversion culvert and to the <br />main disturbed area on its way to the sediment pond. A small 1 ft. deep <br />diversion channel with 2.OH:1.OV sideslopes will be installed around the <br />truck turnaround area, as shown on the sketch. <br />The increase in drainage into the sediment pond is insignificant. <br />Culvert Design - Watershed diversion ditch #1 <br />From the Animas Permit, the peak flow for the watershed diversion ditch <br />#1 is 3.78 cubic feet/second. <br />From the Hydrology and Sediment Yield Work Manual, prepared for OSM, Figure <br />1 shows a a isc arge o cu is ee per second gives a critical <br />depth of 0.75 feet for a 1 foot diameter culvert. <br />do .75 <br />l~ - <br />From Figure 2, the critical slope is determined to be 3.2% which is less <br />than the actual slope of the culvert (4%) so that the flow is inlet controlled. <br />From Figure 3, HW/D is determined as 1.75 feet for outward projecting culverts. <br />Therefore, the headwater required to pass the design flow is 1.75 feet. <br />The culvert will be installed with 2.1 feet of fill above it. <br />Sincerely, <br />r~~eu~~l~~t <br />Greg~ewicki <br />GL/sr <br />cc: Art Van Sant <br />